tag:blogger.com,1999:blog-23236447711096788462024-02-06T21:36:10.880-08:00Evolution InsightsEvolution insights presents evidence of new views of evolution as well as discussion of old and sometimes erroneous views. Other topics of interest to me, and I hope others, are interspersed; primarily views of God, creativity, and science. Current events, major and minor, are also distractions presented.Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.comBlogger220125tag:blogger.com,1999:blog-2323644771109678846.post-61833821272268935632019-09-17T11:47:00.002-07:002019-09-17T11:47:54.382-07:00Final Blog PostWe, the family of Dr. Joseph G Engemann, are grateful for the 90 3/4 years we had him. He left this world on Tuesday, September 10, 2019.<br />
<br />
Here is a link to his online obituary: <a href="https://betzlerlifestory.com/obituaries/joseph-g-engemann-phd.128626">https://betzlerlifestory.com/obituaries/joseph-g-engemann-phd.128626</a><br />
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We hope that his posts will be maintained in perpetuity, and that his thoughts and contributions will inspire current and future generations of those studying evolution.<br />
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<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com2tag:blogger.com,1999:blog-2323644771109678846.post-35803096456340618952019-06-08T08:16:00.001-07:002019-06-08T08:16:17.637-07:00The "Great Dying"An NPR report by Christopher Joyce in the cell phone news reported earlier this week related information about a Smithsonian exhibit's information related to the greatest extinction event known in the history of the earth. The end of the Permian event about 250 million years ago nearly extinguished life on earth and was referred to as the "Great Dying".<br />
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Volcanic activity, with probably some help from asteroid impacts, reduced ice cover and made atmospheric pollution increase global temperatures far beyond the state we now have. Cold climate animals could no longer survive in the arctic regions where they may have thrived on the land mass prior to its breakup into the present continental condition.<br />
<br />
Surface temperatures and absence of polar ice made the cold water input to the ocean bottom stop, or be very slow to replace the bottom water, but the hot surface water would become hotter and make a thicker layer. Water from polar regions would presumably be warmer and lighter than abyssal water, although colder than water from most of the ocean. That water would have an intermediate density that would replace water of similar density under or in the thermocline. The abyssal depths of some ocean basins away from asteroid impact would probably remain relatively unchanged and give refuge from the "Great Dying" to pogonophorans and other species that would provide life to shallower waters after conditions improve.<br />
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The end of Permian extinctions were the worst of the Paleozoic Era and exceed the species deaths of the second worst extinction episode at the end of the Mesozoic Era's Cretaceous Period about 65 million years ago. Pre-Cambrian extinctions may have been more deadly in the two billion years of Pre-Cambrian life, but it is unlikely for much evidence to survive geologic processes.<br />
<br />
DEEP SEA PHYSIOLOGY<br />
<br />
Reports of high rates of oxygen consumption by microbes deep in abyssal sediments seem to be impossible and require a different explanation, although thermal vents and heat from magma could have some interesting physiological implications of which I am unaware.<br />
<br />
The rapid growth of giant tubeworms at thermal vents seems dependent on chemosynthesis by bacteria in special tissue as a source of nutrients; like normal pogonophorans, giant tubeworms lack a functional gut.<br />
<br />
The reduction of diffusion in water under great pressure that I have suggested as the explanation for the dramatically slow aging of deep sea organisms would seem to be greatly modified at higher temperatures of thermal vents and presumably deeper sediment warmed by the core of the earth if the reported rates are correct.<br />
<br />
The abyssal region remains a refuge under siege from plastic and other pollution that may survive our worst climate-altering assaults if anyone will be around a few million years from now to notice.<br />
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Joe Engemann Kalamazoo, Michigan June 8, 2019Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com2tag:blogger.com,1999:blog-2323644771109678846.post-24456501441364302882019-05-29T12:44:00.001-07:002019-05-29T12:44:16.307-07:00Spiral to Radial Cleavage TransitionAnother index card accompanied the one described in the previous post, suggesting the protostome / deuterostome move of retinal nerve fibers from behind the retina to in front of the retina, can be a result of the dorso-ventral inversion mediated by the Pogonophora. This additional card was written on 1/28/2003 and included the following two statements.<br />
<br />
"Somewhere between 10 PM last night and 11:30, I was thinking about the Asellus egg appendage example of embryonic evolution as a model for the embryonic evolution of protostome to deuterostome. It occurred to me that it was a better example than I thought, it may have been for embryo <u>survival</u>, not just metabolic speed for development."<br />
<br />
"Progress seems to have resumed since I started. 45 years with the other explanation: If I am so creative, why didn't I think of it before in those terms? I guess I am not, I'm like everyone else!"<br />
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Why I didn't think of it was almost certainly a result of being overwhelmed with the appendage appearing as a new evolutionary feature of the embryo, and it was not an adult ancestral feature that was incorporated in earlier stages as the abandoned "biogenetic law" would have predicted. In a way, the appendage did incorporate an ancestral feature such as one found in the more primitive Tasmanian isopod as a yolk-filled bulge evolved into an appendage. Although the appendage disappears in the adult isopod, its position makes it a model of a possible base for development of wing precursors in ancestors of insects. The only certain fact is it shows embryonic features can arise without representing a precursor in adult features.<br />
<br />
The reasoning for the spiral to radial transition is speculative but thought to be almost certain because other evidence (1) puts Pogonophora between protostomes and deuterostomes on the tree of life; (2) shows loss of features can evolve more rapidly than gain of features; (3) the deep sea nutrient input is impoverished; (4) reduced egg-shell thickness and loss of early cell specificity are both energy saving developments of deuterostome development. <br />
<br />
Point one above shows us the protostome condition was ancestral. The deuterostome condition evolved by loss of specificity in early cleavage divisions of the fertilized eggs; this may have been due to weakened thin or missing eggshells not providing rigid spatial relationships and signals for development. Loss of such signals made each early division product express the entire genome needed for the "twinning" seen in deuterostome eggs. Cell fate is eventually determined in some deuterostome embryonic tissue as shown by grafts of presumptive leg tissue making additional legs on frogs. But that development may require an interaction of cells in the tissue since the example of cloning individuals from skin cells indicates each cell must have the entire genome.<br />
<br />
More primitive protostomes that have the ability to regenerate tissue or reproduce by fragmentation must have complete genomes in such cells. Notable exceptions are aschelminths such as nematodes that undergo reduction of the genome in cells other than reproductive tissue cells.<br />
<br />
<b>Simplification via pogonophorans is multi-faceted and simultaneously driven by selection for survival in abyssal conditions and survival during episodes of drastic species extinction during periods of asteroid bombardment</b><br />
<b><br /></b>
A. The pogonophorans, as noted above provide a rational explanation for major distinction of the origin of deuterostome development.<br />
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B. Pogonophorans provide an answer for the puzzling inversion of systems noted between protostomes and deuterostomes.<br />
<br />
C. Pogonophoran abyssal adaptation makes their survival during major extinction episodes easier to understand, especially due to their extremely low respiratory rate, extreme longevity, and ability to absorb nutrient at levels found in abyssal sediments.<br />
<br />
<b>The pogonophorans become an evolutionary bottleneck limiting features of deuterostomes</b><br />
<b><br /></b>
A. Hemoglobin is the only respiratory pigment in blood of deuterostomes.<br />
<br />
B. Chitin is reduced in pogonophorans and absent in deuterostomes.<br />
<br />
C. Segmentation is reduced in pogonophorans and absent in deuterostomes, although metamerism is functionally present as a base for deuterostome complexity development almost certainly derived from ancestral segmented features.<br />
<br />
D. The bottleneck entry was via ancestral polychaete annelids. The bottleneck exit to the chordate line was via hemichordates.<br />
<br />
<b>Complexity seen in deuterostomes is probably based on the limited genetic inheritance from the pogonophorans via duplication of gene copies going on to functionally different units. At the same time some older versions may be eliminated due to the vagaries of natural selection.</b><br />
<b><br /></b>
<b>The extreme longevity I first suspected, from the depth pogonophoran tubes must reach in abyssal sediments, seems confirmed by the long-branch attraction shown by pogonophorans appearing in genomic clusters of phylogenies of other major groups.</b><br />
<b><br /></b>
Joseph G. Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan June 29, 2019<br />
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<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-87523131157800607042019-05-24T15:04:00.001-07:002019-05-24T15:04:15.990-07:00Pogonophora "eye"?For many years I carried 3 x 5 cards in my shirt pocket so I could jot down things I wanted to remember or explore. I just came across the following one recently; it was tucked in with some other paper's. Read as follows.<br />
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-----<br />
<br />
1/16/2003 Jan 16, 2003 JGE idea<br />
<br />
1 Pogonophora "eye" as possible intermediate in having retina reverse molluscan condition<br />
<br />
2 Pogonophora (nearly) "straight line" in evolutionary tree with Pre-Cambrian divergences of other groups at various Post-extinction events<br />
<br />
3 TATA box distribution<br />
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-----<br />
<br />
On the back of the card I had only a black spot and an x spaced about two inches apart. the spot and the x are a simple device to demonstrate our blind spot where the optic nerve goes through the retina. By closing one eye and looking at one mark about six to ten inches in front of your open eye and maneuvering the card until the other mark disappears in the blind spot when the brain fills in the void,<br />
<br />
If the x in on the right and I look at it with my left eye, the dot disappears about six inches from my eye when the marks are almost horizontal.<br />
<br />
The squid eye does not have a blind spot because the nerve fibers from the retina lie behind the light sensitive retinal cells. All vertebrate eyes presumably have a blind spot because the nerve fibers from the retina run over the retina until they form the beginning of the optic nerve as they pass through the retina. There, the blind spot is not apparent to us because the other eye fills out the image in the brain.<br />
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The Pogonophora must have retained enough of the eye genes to provide a base for rebuilding the eye. But the inversion as compared to the annelid, mollusk, arthropod line made the light sensitive retinal cells and the nerve fibers reversed in position.<br />
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TATA box things would be worth examining if you are a molecular biologist looking for answers to some related evolutionary steps.<br />
<br />
Pineda <i>et al</i>., 2000, <i>Proc. Natl. Acad. Sci. USA</i>, 97:4525-4529, say "previously demonstrated expression of Pax-6 in planarian eyes, suggest that the same basic gene regulatory circuit required for eye development in Drosophila and mouse is used in the prototypic eye spots of Platyhelminthes and, therefore, is truly conserved during evolution."<br />
<br />
Joseph Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan May 24, 2019<br />
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-44134441268891117252019-04-01T13:35:00.001-07:002019-04-01T13:35:30.682-07:00Surviving Extinction<br />
<div class="MsoNormal">
SURVIVING EXTINCTION EPISODES<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The pre-Cambrian asteroid bombardment may have been preceded
by more spectacular episodes that delayed the evolution and entry of larger
organisms into the perilous environment of earlier times.<span style="mso-spacerun: yes;"> </span>Successful organisms would be dispersed in
most directions and become established to spread the range of those
species.<span style="mso-spacerun: yes;"> </span>At the same time on the
periphery of the range variation and natural selection resulted in new species
when changes made them reproductively isolated from the ancestral ones.<span style="mso-spacerun: yes;"> </span>Well established ones would outcompete and/or
expand the range.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The deuterostomes may never have evolved without the drastic
environment of the early asteroid bombardment.<span style="mso-spacerun: yes;">
</span>Pogonophora are probably ancestral to all deuterostomes.<span style="mso-spacerun: yes;"> </span>Protostomes probably include many groups whose
separation from annelids ancestors was prior to, at the same time, or later than the
separation from annelid ancestors of the first deuterostomes, the pogonophorans.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
SURVIVAL MECHANISMS ON LAND AND SHALLOW SEAS<o:p></o:p><br />
<br />
Many factors that contribute to survival are of value in reproduction and/or dispersal.</div>
<div class="MsoNormal">
<br /></div>
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<b style="mso-bidi-font-weight: normal;">Lucky locations<o:p></o:p></b></div>
<div class="MsoNormal">
Regions remote from impact may have had caverns, sediments,
isolated aquatic habitats and other locations where survival of cysts, eggs,
hibernating stages, or other mechanisms enabled survival.<span style="mso-spacerun: yes;"> </span>Perhaps ice shelves in polar seas protected
organisms beneath them.<span style="mso-spacerun: yes;"> </span>Perhaps marine
forms drifting down to death were sometimes lifted back into survival depths by
a later impact at the end of bombardment.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;">Degrowth</b><o:p></o:p></div>
<div class="MsoNormal">
Fat and some other tissues can be utilized to maintain life
during periods of starvation.<span style="mso-spacerun: yes;"> </span>An extreme
example of degrowth is shown by some jellyfish that are capable of absorbing reproductive
organs and regressing to earlier life stages as they grow smaller.<span style="mso-spacerun: yes;"> </span>They may be able to do that in successive
seasons as they drift from nutrient rich bays to open oceans with less food and
back to nutrient rich locations; the cycle could be part of the annual cycle of
productivity.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;">Absorption of dissolved
nutrients</b><o:p></o:p></div>
<div class="MsoNormal">
All phyla tested, except arthropods, have shown the ability
of some species to absorb amino acids from dissolved amino acids in water at
some stages of their lives.<span style="mso-spacerun: yes;"> </span>The ability
to take up dissolved organic matter from seawater is a particularly important
method of nutrition for species having eggs with little yolk that hatch before
feeding organs are well-developed.<span style="mso-spacerun: yes;"> </span>The
arthropods, with their chitinous exoskeleton, are not equipped to get nutrition
via absorption of dissolved nutrients nor have useful degrowth; this may have
been part of the reason trilobites became extinct at the end of the Paleozoic.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;">Resistant stages<o:p></o:p></b></div>
<div class="MsoNormal">
Overwintering eggs of arthropods such as many insects, fairy
shrimp, and perhaps many other animals have the ability to repopulate a
habitant after adults die from winter freezing or ponds dry and refill.<span style="mso-spacerun: yes;"> </span>Freshwater sponges produce asexual cysts
(gemmules) that have similar use.<span style="mso-spacerun: yes;"> </span>Such
stages are often an important dispersal mechanism for organisms to reach new
habitats via mud on water bird feet, or on mammal fur.<span style="mso-spacerun: yes;"> </span>The stages may survive a trip though the
digestive tract during dispersal.<span style="mso-spacerun: yes;"> </span>Such
mechanisms were probably partially selected by the value of providing a new
generation into the areas of greatest damage after an extinction event before
others lacking such a survival mechanism arrive and become competitors or predators.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
THE ABYSS AS A REFUGE<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The abyssal portion of the ocean is the most widespread area
of the earth and the depth and stratification of the overlying sea make it
likely that much of it would be relatively untouched by an asteroid or two
sending catastrophic waves over land and shallow seas killing most organisms that
did not have protected refuges (caves or burrows etc.).<span style="mso-spacerun: yes;"> </span>Those not destroyed still had to find food
and other requirements for survival.<span style="mso-spacerun: yes;"> </span>The
peak of bombardment was followed by a reduced supply of remnants of the
fractured planet that occupied the zone between Mars and Jupiter.<span style="mso-spacerun: yes;"> </span>One big one, like the last one the helped
finish off the dinosaurs, produced many extinctions and opportunities for newly
evolving species to take over roles of the extinct forms. <o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The pogonophorans would continue to expand range and send
descendants into new areas.<span style="mso-spacerun: yes;"> </span>Other groups
would also be testing new environments, for example, the crinoids appear to
have had adaptation to abyssal conditions and retained many of the adaptive
features after repopulating the shallow seas after the worst of the bombardment
was over.<span style="mso-spacerun: yes;"> </span>Pogonophorans have been found
in a few locations in sediments only a few hundred feet deep, but the many
vertebrates and the connecting groups diverged from their common ancestors
almost a billion years ago with origins at various depths and locations where
some stability of the environment with hospitable conditions existed.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The specificity of environmental adaption for deep sea
animals has been shown by the limited range of a few hundred meters isolating
similar species to nearby depressions surrounded by other related species encircling
the surrounding abyssal area.<span style="mso-spacerun: yes;"> </span>Such
environmental specificity should not be a surprise when you see how uniform the
alpine limit of the tree line can be.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<u>Some key features that enabled pogonophorans to survive in
their abyssal habitat included</u>:<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
A very slow metabolism compatible with survival on sediments
receiving very little nutrient input in the form of amino acids from slowly
decaying organic debris (perhaps supplemented by surface waters raining down
organisms killed by the surface disturbance).<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The depth of their tubes enabling survival from attacks by predators.<o:p></o:p><br />
<br /></div>
<div class="MsoNormal">
The slow reproductive rate and growth rate allowing
reproduction hundreds of years after the worst of conditions.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Their hemoglobin and circulatory system enabling adequate oxygen
to be stored and or transported to the posterior end where nutrients were absorbed in
anaerobic sediments.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Planktonic larvae capable of dispersal over great distances and
time to repopulate large devastated areas of sea sediments.<span style="mso-spacerun: yes;"> </span>Those that did not progress to shallower seas
are still much the same as the pre-Cambrian ancestral stage of the line ancestral
to chordates.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Joseph G. Engemann<span style="mso-spacerun: yes;"> </span>Emeritus
Professor of Biology, Western Michigan University<o:p></o:p></div>
<div class="MsoNormal">
<span style="mso-spacerun: yes;"> </span>Kalamazoo, Michigan<span style="mso-spacerun: yes;"> </span>April 1, 2019 (no fooling)<o:p></o:p></div>
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<br /></div>
<div class="MsoNormal">
<br /></div>
Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-7767620994611626682019-03-19T18:04:00.001-07:002019-05-06T13:16:42.819-07:00Pogonophora - Central position in evolution<br />
<div class="MsoNormal">
Pogonophora: Their spectacular role in animal evolution<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;">A spectacular
connection of the two main higher animal groups<o:p></o:p></b></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><br /></b></div>
<div class="MsoNormal">
<u>Early embryology of the two main lines of animals<o:p></o:p></u></div>
<div class="MsoNormal">
<u><br /></u></div>
<div class="MsoNormal">
<span style="mso-spacerun: yes;"> </span>The Pogonophora
show how the radial and indeterminate cleavage of deuterostomes (echinoderms, hemichordates
and vertebrates) came about from pre-Cambrian annelids in the deep sea while
other annelids retained the spiral and determinate cleavage of protostomes as
they were giving rise to arthropods and mollusks.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<span style="mso-spacerun: yes;"> </span>The deep sea had
low input of nutrients that put a premium on not investing in heavy egg shells
that protected eggs of protostomes as they were confined in the spiral pattern
of cleavage, a confinement that was released by less confining outer membranes
that allowed a more direct radial cleavage pattern.<span style="mso-spacerun: yes;"> </span>At the same time radial cleavage did not
produce the immediate cell fate into a particular tissue, thus making possible
more than one viable embryo from a single egg as each of the early cleavage
cells retained all of the development potential of the original egg.<span style="mso-spacerun: yes;"> </span>The ability to complete development without
all the original cleavage products had high survival value in the rigorous deep-sea
environment, although details are speculative.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<span style="mso-spacerun: yes;"> </span>My comparative
study of Tasmanian and Michigan isopods included observation of the impact of the
egg membrane’s role in confining development, leading to a unique egg
appendage, a clear indication that evolution can occur in developmental stages
independent of adult development.<span style="mso-spacerun: yes;"> </span>(see
more on “Origin of deuterostome embryology” in blog post dated 6/24/2013)<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;">Systems inversion<o:p></o:p></b></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><br /></b></div>
<div class="MsoNormal">
<u>A simple process</u><o:p></o:p></div>
<div class="MsoNormal">
<u><br /></u></div>
<div class="MsoNormal">
The inverted position of blood vessels, nerves, oral
openings of deuterostomes as compared to protostomes (especially the ancestral
annelids of both groups) was proposed as evidence of the central role of
annelids in evolution of higher animal phyla.<span style="mso-spacerun: yes;">
</span>The original reason for rejecting the theory was the drastic difference
in early embryology of the two lines of animals.<span style="mso-spacerun: yes;"> </span>The next reason thought to negate the annelid
theory as well as the embryological argument against it was the use of
nucleotide and other molecular data.<span style="mso-spacerun: yes;">
</span>Such data must be realigned taking into consideration the effect of the
astronomically slow rate of genetic change in the pogonophorans ancestors.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<u>Inversion, the first step<o:p></o:p></u></div>
<div class="MsoNormal">
<u><br /></u></div>
<div class="MsoNormal">
The inversion of annelids began with certain polychaetes
that began living vertically in tubes they secreted, as seen in <i style="mso-bidi-font-style: normal;">Sabella</i> and many other shallow water
polychaetes.<span style="mso-spacerun: yes;"> </span>As those growing in
progressively deeper water, with less food, became dependent on absorption of
nutrients in pore water of the sediments they outcompeted those wasting energy
on producing a mouth and some bilateral structure.<span style="mso-spacerun: yes;"> </span>This stage is still found in abyssal
pogonophorans.<span style="mso-spacerun: yes;"> </span><o:p></o:p></div>
<div class="MsoNormal">
<span style="mso-spacerun: yes;"><br /></span></div>
<div class="MsoNormal">
<u>Inversion, the second step</u><o:p></o:p></div>
<div class="MsoNormal">
<u><br /></u></div>
<div class="MsoNormal">
The return of descendants to shallow seas occurred once the
worst episode of pre-Cambrian asteroid bombardment eased.<span style="mso-spacerun: yes;"> </span>As they arrived in shallower more nutrient
rich areas, they reformed the remnants of their digestive system with a new
mouth on the former dorsal side which became the ventral side, as they groped
around the sediment surface near their tube, finding food particles that pushed
the epidermal and gut layer together triggering mouth formation on the former
dorsal surface without the restriction of the nervous system that originally had encircled the esophagus.<span style="mso-spacerun: yes;"> </span>Other
clues to this step are presented by the parallels of endocrine hormone
function, transport, and structural similarities of vertebrates, arthropods,
and annelids.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;">Protostome-Deuterostome
links<o:p></o:p></b></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><br /></b></div>
<div class="MsoNormal">
<u>Segmentation/Metamerism<o:p></o:p></u></div>
<div class="MsoNormal">
<u><br /></u></div>
<div class="MsoNormal">
The segmentation of annelid type was found on a short portion of
the most deeply embedded part of some pogonophorans; it included setae that are
a very annelid like characteristic.<span style="mso-spacerun: yes;"> </span>A
few anterior regions are noticeable but without the posterior segmented region it would be difficult to make an annelid connection.<span style="mso-spacerun: yes;"> </span>The metamerism of chordates such as ourselves
seen in bone, muscle, nervous system and blood vessels is now easily
understandable with the intermediate stage of pogonophorans.<o:p></o:p></div>
<div class="MsoNormal">
The transition from pogonophorans to chordates is best shown
by the larval stage comparisons of pogonophorans and hemichordates.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<u>Molecular evidence</u><o:p></o:p></div>
<div class="MsoNormal">
<u><br /></u></div>
<div class="MsoNormal">
Molecular features of several types show greater similarity
between deuterostomes and advanced protostomes than their earliest variants
found in more ancient protostomes once thought to be the closest common
ancestors at the protostome-deuterostome split.</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<o:p></o:p></div>
<div class="MsoNormal">
DNA/RNA studies of evolutionary relationships at the phylum
level need reevaluation because major ones have ignored the mutation rate
differences associated with generation times.<span style="mso-spacerun: yes;">
</span>Many well focused studies have shown generation time does affect
evolution rates.<span style="mso-spacerun: yes;"> </span>One impact has been the
Pogonophora showing up in many odd places in phylogenetic trees because they
are almost unchanged since their divergence from major groups that have
diverged even more from more recent relatives.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Six other posts, from June 17 to June 20, 2013 have
additional clarification of the points made above.<span style="mso-spacerun: yes;"> </span>The second June 30<sup>th</sup> post of that year
is an annotated bibliography that has some emphasis on protostome/deuterostome
comparisons.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Joseph Engemann<span style="mso-spacerun: yes;"> </span></div>
<div class="MsoNormal">
Emeritus Professor of Biology, Western Michigan University, Kalamazoo,
Michigan<span style="mso-spacerun: yes;"> </span>May 19, 2019<o:p></o:p></div>
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com1tag:blogger.com,1999:blog-2323644771109678846.post-58408058069496735612019-03-04T11:36:00.000-08:002019-05-06T13:28:11.039-07:00ENVIRONMENT AND NATURAL SELECTIONHOW THE ENVIRONMENT AFFECTS NATURAL SELECTION<br />
<br />
The environment makes no conscious effort to select traits of an animal or plant beneficial to itself or the organisms resident in its habitats. If the location is in a suitable part of the range the animal occupies, it can contribute to survival and reproduction of the animal, especially of genetic variants having the genetic features best adapted to the environment. An animal may select the environment, although it may not be a conscious act. Foraging to new areas is less likely to occur when food and housing are abundant so a search does not take the organism to new areas.<br />
<br />
Some examples of how the environment passively results in natural selection of animal features you are already familiar with-<br />
the streamlined shape of fish (and birds), tapered at each end so resistance to movement through water (air) is minimized. The obvious exceptions, as in baleen whales, occur when feeding or some other benefit is more important in their lives.<br />
coloration blending with the visual background. Again, exceptions occur when attracting a mate or warning predators of your toxic properties is more beneficial to survival.<br />
fur or feathers aiding temperature regulation at the same time providing physical protection such as abrasion resistance, flotation, and a mechanism for seasonal color change.<br />
appendage modification improving function for climbing (claws), digging, feeding, and locomotion to name a few.<br />
<br />
THE LUNG AND BONY SKELETON CONNECTION<br />
<br />
A less familiar example, unless you have a background in evolution and marine biology, is the difference between the cartilaginous and modern bony fishes and the role of air breathing fish in the evolution of bony skeletons. Survival of fish in anoxic ponds or ones that temporarily dried up, selected fish having more mouth surface able to extract oxygen from water or air. Ultimately, a pocket becoming the lung of lung fishes, then of amphibians and eventually reptiles, birds, and mammals in one line and from the fishes the early lung was adapted to the air bladder/swim bladder enabling evolution of the modern bony fishes.<br />
<br />
It is interesting that the bony fish in the ocean had their origin in fresh water. Sharks and other cartilaginous fish do not have fresh water fish in their ancestry. The flotation provided modern fish by the air bladder offsetting the extra weight produced by bone, as compared to the weight of sea water, is partially provided by oil and/or fat stores for cartilaginous fish for excess of weight of bodies heavier than sea water. Some compensate by continuous swimming providing "lift" from wing-like pectoral fins or body shape.<br />
<br />
SUBTERRANEAN AND ABYSSAL SIMILARITIES<br />
<br />
The deep sea abyssal region and subterranean aquatic environments have both similarities and differences. The similarities usually include absence of light, stability of temperature, no green plants, low input of food, low predator density, cool temperatures.<br />
<br />
In response to those features of the environment there is no selection eliminating loss of vision, pigmentation, and defensive weapons. Slender, elongated appendages provide some adaptation for loss of vision, They may also enable walking on soft, unstable sediment accumulations and sensory input for feeding.<br />
<br />
SUBTERRANEAN AND ABYSSAL DIFFERENCES<br />
<br />
The abyss<br />
Soft sediments dominate abyssal environments and currents probably cause less erosion and relocation of sediment. Temperature away from thermal vents are slightly above the freezing temperature of water. Invertebrate species present are from major groups first found in sediments from older sediments that were in near shore environments (Jablonski et al., 1983; see references at end of the June 22, 2013 post of this blog).<br />
<br />
This trend to migrate to deeper water and newer related groups evolve in shallower sea areas was not documented for abyssal species but seems to be a reasonable projection.<br />
<br />
Temperate Zone Caves<br />
Numerous instances of cave dwelling crustaceans were originally lumped into one or a few species with what were thought to be their closest relatives in other caves. Later research showed their closest relatives were in surface waters adjacent to the caves; the rapid adaptation to cave dwelling led to similar loss of pigmentation and vision of less value in showing their evolutionary origin in post-glacial times. This is one example of how rapidly evolution can occur to bring about the loss of characteristics of little use but essential to survival in a different environment.<br />
<br />
EXTREME PRESSURE<br />
https://evolutioninsights.blogspot.com/2013/06/evolution-in-deep-sea.html<br />
notes the factors thought to be responsible for slow metabolism and increased longevity in abyssal animals. I speculate that the slight compression of water at great depths decreases molecular mobility and so called Brownian movement noted with oil immersion microscopic viewing of cells and related particles; this could be a major factor in the slow pace of life and evolution in the abyss. I have not searched the literature for related research for many years, One suggestion in an older article about pressure interference with cell activities was the variable rate of compression of organic compounds could stop or reverse the direction of action toward the product most greatly compressed. If so I would think alternative metabolic pathways might evolve, but oh so slowly under abyssal conditions.<br />
<br />
It seems to me that it would be simple for a physicist or chemist with access to equipment with extreme pressure to compare the rate of diffusion from a grain of dye, or the rate of sedimentation of fine particles, or both to a range of pressures. ( see blog noted above for reference to Yayanos, Dietz, and Boxtel 1979 study of pressure effects on growth)<br />
<br />
My nebulous account of factors enabling understanding of the pogonophoran story is, unfortunately, not easily told in a concise way. The scattered threads that lead to understanding of the story is perhaps inaccessible to many viewing one of the disconnected bits I provide. It took a lifetime for me to see the things I present. I hope others do it more easily and find the trip interesting. If you see what I am attempting to say, I encourage you to point it out to Wikipedia. You will need to include a few scientific journal references noted elsewhere in this blogsite to have any hope of others resisting the urge to expunge the entry as not being in sync with existing views. It is normally good, but preserving the <i>status quo</i> can be a major stumbling block to creativity.<br />
<br />
Joseph Engemann Kalamazoo, Michigan March 4, 2019Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-557598494743985802019-02-12T13:24:00.000-08:002019-02-12T13:24:51.278-08:00ReflectionsThinking that my days are limited made me want to make sure that the things I have to contribute to understanding the major features of the evolutionary tree of life are passed on to the next generation. I think this blogsite has enough information to do the job if it is studied by a well-trained biologist.<br />
<br />
THE BODY CAVITY<br />
<br />
Others apparently have found the 2/17/15 post on the body cavity of interest since over half of the pageviews each month are to that post. I suspect it is assigned reading in some classes on several continents because of the clustered nature of the country sources of the views. The post was included almost as an afterthought to supplement coverage of evolutionary discussion of body systems.<br />
<br />
Its major interest to me was the minor bit about formation of openings where layers of bare ectoderm and entoderm cells meet. That can help one understand the new location of the mouth of deuterostomes when the connecting link, the pognophorans, emerged upside down (compared to protostome ancestors) as they re-entered coastal waters following extinction events. The resulting inversion of systems of deuterostomes, as compared to protostomes, was discussed in the post dated June 28, 2013. This process enabled fusion of ganglia to a compact brain close to sensory inputs of a head in an anterior position enabling short and speedy neural connections as the owner probed the environment. Perhaps this phenomenon is best illustrated by birds and their ability to fly through a sea of tree branches.<br />
<br />
THE DEEP SEA<br />
<br />
Structure of the ocean and its physical state under great pressure needs to be understood to see how the pogonophorans can survive the many generations virtually unchanged in the deep sea while their wandering descendants evolve to produce the deuterostomes in shallow water. Several old and some recent posts address this issue. The common ancestry of all deuterostomes with a close relative of the earliest annelids explains why nucleic acids produce odd results in some erroneous molecular phylogenies. The results are only odd because they complicate phylogenies calculated with invalid assumptions of uniform rates of genetic changes in evolution.<br />
<br />
THE POGONOPHORA<br />
<br />
These tubeworms represent survivors of an evolutionary bottleneck, the deep-sea, where they developed a new type of embryonic development (or cleavage), lost blood pigments other than hemoglobin, and lost the ability to make chitin in the stem group leading to vertebrates.<br />
<br />
The blood vascular system was needed to store and transmit oxygen to the portion of the worm embedded in anaerobic sediments. A functional digestive system was reduced to near disappearance and it reformed in a way that did not penetrate the brain in descendants moving to shallow sea areas.<br />
<br />
REGRESSIVE EVOLUTION<br />
<br />
It is counter-intuitive to give importance to regressive evolution when we think about the grand scheme of evolution going from the first small cells to the diversity of size and complexity of the world of life today. Simple to complex, or progressive evolution, is the explanation our intuition provides.<br />
<br />
So the loss of a functional digestive system seems counter intuitive and hard to accept as a way forward to the vertebrate gut from the "degenerate" pogonophoran reduction or loss. Paleontologists found the simple to complex markings on certain cephalopod shells actually went from complex to simple as the fossil record was better developed in their collections.<br />
<br />
In regressive evolution, the regressing feature may be targeted for loss indirectly by the better survival of organisms that no longer need the feature; any mutations causing less nutrients to go to such a feature leave the organism more for better reproduction. The speed of regressive evolution can be much faster than progressive evolution. Both can be happening at the same time.<br />
<br />
The largest animals are a remarkable example of regressive evolution in the whale's adaptation to aquatic life. All that process of evolution through four-legged ancestors to some with remnants of leg bones no longer used is one example of loss or regressive evolution while other adaptations are evolving.<br />
<br />
The annelid worms provided an important feature in our evolution by the segmentation or metamerism producing a series of duplicated structures that could produce different structures in different parts of the body. The phenomenon is graphically illustrated by the appendages of the crayfish in the protostome line of animals.<br />
<br />
MOLECULAR SIMILARITIES<br />
<br />
We share many molecular features with other organisms. Nucleic acids and biochemistry of energy production are even shared across kingdom boundaries. More specialized biochemical functions often are shared by coelomate protostomes and deuterostomes having closely related compounds although simpler molecular versions may also be found in more ancient protostomes.<br />
<br />
Neurosecretions, biochemistry of vision, and biochemistry of metameric processes have similarities that help make the pogonophoran link of deuterostomes to protostomes much more obvious than is generally recognized.<br />
<br />
DO NOT FORGET<br />
<br />
Pogonophorans are the only animals with structural features demonstrating the transition from annelid to deuterostomes. They explain the importance of their deep-sea life in the regressive evolution leading to a new type of embryology in the deuterostomes, their survival during extinction events, their extremely low metabolic rate enabling long life and slow evolution in the impoverished environment of the deep sea.<br />
<br />
Joseph G. Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan February 12, 2019 (Happy 128th birthday, Dad)<br />
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<br />
<br />
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<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-190697174853943792019-01-22T13:48:00.001-08:002019-01-23T13:41:24.437-08:00Trump Evaluation Quiz<b>Throw the rascals out</b>-<br />
<br />
seemed to be the creed attracting the Trump followers. There was some value seen to rooting out entrenched legislators who appear to be at the beck and call of money and power brokers. But the cure turned out to be worse than the disease. Bi-partisanship seems to have vanished with the death of John McCain.<br />
<br />
The art of the deal seems to consist of insults, lies, extortion, deceit, and bribery. Trusted authorities are those who agree with you. Sometimes it seems Fox News, Rush, Sean, and Kelly may provide unbiased analysis so I can't automatically condemn their statements. A Trump deal appears to be a solution tailored to his request. His imposition of a government shutdown looks like an attempt to extort money for the wall from congress. But he probably won't accept any compromise until the lack of funds ends the FBI investigation of his alleged wrong deeds.<br />
<br />
For each topic below, read the statements under the topic heading, Then on the line in front of the topic enter a "T" if the statement(s) is (are) true; enter an "F" if the statement(s) are false or fake news.<br />
<br />
<b>_____ INSULTS</b><br />
<b><br /></b>
Trump started debates of presidential contenders of his party by focusing on the one he probably thought was most vulnerable to nasty comments. He continued to pick off others, often minimizing their strengths as failings. Insults are readily applied to those opposed to any view of his.<br />
<br />
<b>_____ LIES</b><br />
<b><br /></b>
His tweets on Twitter as well as more formal presidential statements are full of self-contradictions, It seems that any thing supporting or opposing a particular view could be documented by his utterings. Is he guilty of lies, memory lapses, mental processing failures, or some combination of all of the above? His lies directed at others often seem to be projections of his own failings.<br />
<br />
<b>_____ EXTORTION</b><br />
<b><br /></b>
The government shut-down is his doing. He seems to think blaming democrats for it will make them agree to his demands. That it is a ploy for something else seems indicated by his stomping out of a meeting he arranged with two congressional leaders.<br />
<br />
<b>_____ DECEIT</b><br />
<b><br /></b>
Circumstantial evidence points toward keeping his income statements under wraps so profiting from bankruptcies, Russian contacts, and shady deals won't be seen. Unreported control of foreign financial accounts could be evident and lead to unreported campaign financing. I thought he talked a lot about Hillary's email and other problems before they were publicized and before the Russian influence was evident. It was easy for me to think he had advance clues from them, perhaps from suggestions he dropped.<br />
<br />
<b>_____ BRIBERY</b><br />
<b><br /></b>
I can't believe his lawyer took care of his girlfriend problems without some instruction.<br />
<br />
<b>_____ LACK OF EMPATHY</b><br />
<b><br /></b>
His off-the-cuff remarks show little sensitivity to humans. His reading from the scripts his speech-writers put on the teleprompter make me think he is a sensitive person. But tweets confirm the insensitivity and lack of appreciation for anyone of other sex, race, national origin, political view, and not visible in his mirror. If it were not for this problem we would have far fewer children separated from their parents, fewer people born in this country and living admirable lives while facing deportation.<br />
<br />
<b>Results</b> 5 or 6 T's, watch Fox News sometimes; 5 or 6 F's, watch CNN sometimes; 3 or 4 T's or F's, its a puzzling world, isn't it.<br />
<br />
Other than the above, and messing with medical care, the economy, foreign relations (did you see the recent clip of his elbowing a head of state out of the way so he could be front and center of a photo-op during a foreign meeting?), and causing an exodus of experienced leadership in government departments- well, other than that he isn't doing bad and God still loves him.<br />
<br />
Joe Engemann Kalamazoo, Michigan January 22, 2019Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-90876087521795051262019-01-17T21:46:00.000-08:002019-01-17T21:46:37.283-08:00Variable Rates of Extinction and Evolution<b>A New Theory?</b><br />
<br />
While composing the previous post about the status of survival/extinction of the Tasmanian tiger I thought of the impact of impending extinction on rates of evolution. It may be discussed in literature I am not familiar with, but it was new to me; perhaps the first new idea about evolution that I have had in ten years and certainly the first since I turned ninety last year.😊<br />
<br />
The theory of "punctuated equilibrium" in rate of evolution proposed by Gould has largely been abandoned as variation caused by probable artifacts of sampling problems faced by paleontologists. The assumption of a uniform rate underlying known variability around such a rate has been accepted by many molecular phylogeny researchers and caused the errors in our understanding of the relationship of major phyla to one another as shown by the sixth post on this blog site posted 5/31/2013.<br />
<br />
<b>The Tasmanian tiger</b><br />
<br />
Maybe it is extinct, maybe it is surviving in remote areas of Tasmania and/or continental Australia. But the bounty on them in Tasmania reduced them to such a small population that there has not been accepted evidence of them in the past few dozen years. Could some have learned to avoid inhabited areas or developed excellent ways of avoiding human contact? Not doing so could have eliminated those lacking such skills during the time the bounty was effective.<br />
<br />
Genetic diversity<br />
<br />
A reduced population makes it likely that some genetic diversity is lost and thus adaptability and the chance of surviving becomes more limited, possibly causing further loss of genetic diversity and ultimate extinction. Extinction from such an event is not as dramatic as extinction from natural disasters such as asteroid impact, disease, introduced predators, climate change, and evolution of better competitors.<br />
<br />
The ecology of extinction and expansion of range<br />
<br />
There are many causes of both factors. In a stable environment competition is a major factor as some balance is reached if the less well adapted species can specialize in utilizing a part of its environmental resource of food and housing more effectively or, alternatively, utilize a greater range of resources. Migration and other factors may also be part of the equation.<br />
<br />
Either being a specialist or a generalist can be an effective way of competing for survival, The generalist probably will yield a greater diversity of new specialists following a major extinction event. The best specialists may also do well and dominate in the same post extinction time. If overspecialization occurs a species may become extinct earlier during a major extinction episode.<br />
<br />
Species differ in their habitat requirements. Large predators typically require large suitable areas. Fragmented habitat may make life difficult for many species although connecting corridors of suitable habitat can help survival. The prey species of predators also have their special requirements. For the Tasmanian tiger, life may have been difficult to sustain because many of the medium sized marsupials of forests are adapted to tree-dwelling. Kangaroos and larger wallabies are more likely be in more sparsely forested habitats.<br />
<br />
Human activities would seem to be generally detrimental to survival for many species. Besides our causing reduction of favorable habitat, pollution, introduction of pest species, and our general lack of awareness of the damage we do should put us in awe of the survivors. The good that we do by providing some food at critical times can be canceled by the danger feeding stations provide for disease transmission as well as sites attracting predators. The natural spacing of species and their survival is more likely to be enhanced by well-designed land conservancy programs.<br />
<br />
In retrospect, I do not have a new theory, it is just awareness of the complexity and breadth of application of existing ones.<br />
<br />
Joseph Engemann Kalamazoo, Michigan January 18, 2019 Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-84519748998887883272019-01-15T14:35:00.001-08:002019-01-15T14:35:35.818-08:00The Tasmanian Tiger, Extinct, or Not?<b>The uncertain state of affairs</b><br />
<br />
The question of exinction of the Tasmanian tiger (the thylacine) was raised in an interesting article, "Paper Tiger" (Brooke Jarvis, <i>The New Yorker</i>, July 2, 2018, pp. 44-54). According to Jarvis, the last one in captivity died in a Hobart, Tasmania, zoo in 1936. That was twenty years before I arrived and was mentored by Dr. Eric Guiler, an expert on many Tasmanian zoological topics, during my year as a Fulbright scholar at the University of Tasmania.<br />
<br />
On several field trips with Dr. Guiler (see endnote), and others by myself, many other animals or their sign, such as tracks or droppings were seen. But such lack of evidence is not very convincing because- such rarities as the Tasmanian devil and the platypus I only saw in zoos, Michigan mammals known to exist but seldom seen outside of zoos include badgers, bobcats, cougars, flying squirrels, mink, and otters.<br />
<br />
It seems reasonable that with the bounty put on tigers, to reduce their predation on farm animals, their numbers may have been reduced beyond their ability to survive. But Tasmania has much uninhabited potential tiger habitat where few would have chances to observe them. Some suspect that some may still survive in wild country along the north coast of the Australian mainland. Both are plausible, but seem to require better documented evidence than is presently known.<br />
<br />
<b>A few potential factors</b><br />
<br />
In favor of their non-extinction is the possibility those most adapted to avoiding humans may have left some survivors. Anecdotal reports would seem to support this view. But the ease for humans to see what they want to see has caused the shooting death of numerous hunters and a few cattle during the hunting season in Michigan; eye-witness testimony is of questionable reliability.<br />
<br />
Extinction is perhaps more likely when numbers are greatly reduced. Habitat reduction is one cause. But small numbers may increase inbreeding and thus increase the likely of mortality due to deleterious genes. Small numbers can also interfere with opportunities for mating and consequent reproduction. Other factors may also operate if social learning is involved, although I have not heard of Tasmanian tigers forming packs.<br />
<br />
Extinct or not, it is still an open question. Negative facts and hypotheses such as extinction are very difficult, if not impossible, for a scientist to prove.<br />
<br />
endnote: Dr. Guiler is the one standing to the left in the picture in post number 51 -<br />
https://evolutioninsights.blogspot.com/2014/06/the-baleen-whale-tooth.html<br />
<br />
Joseph G. Engemann Emeritus Professor of Biology Western Michigan University, Kalamazoo, Michigan January 15, 2019Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-20389634742078073332019-01-07T11:07:00.001-08:002019-01-07T11:07:48.602-08:00THE EARLY CAMBRIAN SPECIES EXPLOSIONThere seems to be a burst of energy put into discovering new species that add to knowledge of the diversity of life in the Cambrian and earlier fossil fauna described in Gould's book about the Burgess Shale deposits in the Rocky Mountains of Canada. A recent issue of <i>Science </i>summarizes the results of the summer fossil collecting season of an additional site not far from the Burgess Shale site. Additional sites, especially in China, are major locations of fossils from the same general time over 540 million years ago,<br />
<br />
The discoveries are largely more of the same - arthropod groups, some now extinct, and some ancestors of relatively rare living groups such as horseshoe crabs and onychophorans that have not greatly changed. Ancestral trees show relationships of major arthropod groups appearing rapidly during a few million years of time.<br />
<br />
I do not have much hope of researchers finding fossils that clearly show the origins of annelids and mollusks more than indicated in earlier posts of this blog. It is a little bit like me, not much is new since I turned ninety.<br />
<br />
Joe Engemannn Kalamazoo, Michigan November 30, 2018<br />
<br />
The issue from the mid-November <i>Science</i> issue had a bit about discovery of a method providing information about epithelial layers formerly thought to be unable to present fossil evidence. It seems unlikely to provide reliable evidence leading to wholesale understanding of gross aspects of fossil structure, although interesting information seems to be revealed.<br />
<br />
Arthropods ancestral to known groups may have not provided fossil evidence for a number of reasons such as - inaccessible ancient rock strata, lack of structures that fossilize, Isolation of one or more small sub-populations of a species provides opportunities for more rapid development of new species.<br />
<br />
My shutdown of blogging for the past month had nothing to do with the current government shutdown other than my wasting my time thinking about the ridiculous current events.<br />
<br />
Joe Engemann Kalamazoo, Michigan January 7, 2019<br />
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-85000488403502327382018-10-02T14:48:00.001-07:002018-10-23T20:06:12.765-07:00Science: Understanding Statistics<u>Numbers</u><br />
<br />
Numbers are meaningless by themselves for people that are not studying arithmetic or a related subject. But we can all compare numbers and determine if one is bigger or smaller. There is an old caution about people using numbers that notes "figure don't lie, but liars can figure." Dr. Clark, teaching a biostatistics class, and later a member of my doctoral committee was comfortable telling an old joke about the statistician that drowned crossing a stream that averaged one foot deep. I am currently puzzled by how I would know how many beers before I would sleep or blackout. I haven't had a beer in over thirty years, and I found out over thirty years before that, that four was too many for me in one evening. I seldom drink now, just an occasional small glass of wine or a drink traditionally garnished with olives, although I much prefer a glass of water.<br />
<br />
<u>Divorce rates</u><br />
<u><br /></u>
Our local paper has a front page story today, October 2, 2018, having the largest and first title "<b>Millennials are causing the U.S. divorce rate to plummet"</b>. The author of the article credits an analysis by a sociology professor using "U. S. Census Bureau survey data. Others are cited who note boomers had married earlier and had a higher divorce rate. Other factors are discussed that show how commitment and employment opportunities for women may be reflected in the numbers.<br />
<br />
<u>Toxic substances</u><br />
<br />
Newspapers, magazines, and news programs are full of frightful stories about contamination or dangers of our food, water, medicines, and environment. You are right to be concerned, and something should be done, but realize presence of some dangerous substances can be determined to number of parts per trillion (ppt). Back fifty+ years ago, when I was a member of the Midwest Benthological Society and a graduate student studying bottom dwelling aquatic organisms and water pollution, few substances could be identified at concentrations less than one part per million,<br />
<br />
<u>Exposure limits</u><br />
<br />
When tests associate the lowest level at which damage to test organisms is shown, permissible levels were typically set by regulatory agencies at one percent of the <b>lowest</b> exposure which produced problems. Consideration should be given to other factors such as is it accumulated in tissues of an organism, is it persistent or does it break down naturally, how it interacts with other substances, and is it degraded or converted into other substances of concern.<br />
<br />
<u>An extreme example</u><br />
<br />
In the early 1960's when I was teaching at Western, I was prepared to testify at hearings for the planned Palisades Nuclear Power plant regarding their proposal to release very slight concentrations of radioactive elements in the expected cooling water releases into Lake Michigan. Zero release was part of the final plan. The seemingly small amounts had some elements that previous research (by others) had been shown to be concentrated by 30,000 times over the concentration in which they lived. Take that concentration and note how they might be fed upon and concentrated in the food chain, or get filtered out an the beach, and the possibilities are frightening. Fortunately, no releases were permitted.<br />
<br />
In most cases, one part per trillion (a million of them to make one part per million) is not of itself a big danger. But it does mean it might be coming from a more dangerous source that should be identified.<br />
<u><br /></u>
<u>Food labels</u><br />
<u><br /></u>
Helpful, but ingredient lists can be more misleading than percent daily values. Your jam or jelly may list a fruit first showing it is the most abundant food in the product. But when you add up the later listed sugar, fructose, glucose, honey, and water, it would be possible that less than 20% is fruit and over half could be some form of sugar. And if you are diabetic, you know the sugar content of fruit eaten may increase blood sugar more rapidly than the sugars released by digestion of carbohydrates, thus drinking some orange juice is more apt to rapidly restore blood sugar levels reduced by a moderate overdose of insulin (this is not medical advice, just an aide to understanding an aspect of biology, consult your physician). For more on glucose see the April 25, 2014 post "Evolution of Carbohydrates".<br />
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Joseph Engemann, Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan October 2, 2018<br />
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<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-6187920655318754272018-09-28T14:06:00.001-07:002018-09-28T14:06:18.006-07:00GLOBAL WARMINGThose of us living in temperate climates have winters and summers that clearly tell us weather can be cyclical, even dependably so when orbits around the sun bring recurring variations. Less certain variations can add to or reduce the annual weather patterns. A book that helped me understand more of how those variations impact our climate was published in 2009. The author is perhaps the best informed climate scientist and deserves getting his message spread.<br />
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<i style="font-weight: bold;">Storms of My Grandchildren </i>by James Hansen (2009, Bloomberg USA, New York, 303 pages) notes on page xv of the preface that "Global warming does increase the intensity of droughts and heat waves, and thus the area of forest fires. However, because a warmer atmosphere holds more water vapor, global warming must increase the other extreme of the hydrologic cycle--meaning heavier rains, more extreme floods, and more intense storms driven by latent heat, including thunderstorms, tornadoes, and tropical storms."<br />
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He had given related testimony to a Senate committee in 1988. His earlier 1981 paper in <i style="font-weight: bold;">Science </i>"described likely climate effects of fossil fuel use". And apparently was why "the Department of Energy reversed a decision to fund my research, specifically citing criticism of that paper as being alarmist."<br />
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The book makes one realize that money and politics inordinately influenced policy decisions beyond rational levels in the past as they do today. Pages 124-139 added to my understanding of that.<br />
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I have had a few recent posts telling some of how the oceans have influenced evolution by their layered structure. Hansen, on page 101, says "If we can measure how much the oceans are warming, we will know not only how much additional global warming is in the pipeline but also how much we must reduce the human-made forcing if we want to stabilize climate."<br />
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If you want to know more he has some good suggestions and explanations. The most significant new one to me was the safety and efficiency of fourth generation nuclear energy which could operate safely using up the nuclear waste our first generation nuclear plants have generated (about 6 pages beginning on page 194 of chapter nine).<br />
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The solution isn't simple, the causes of global warming interact in sometimes uncertain ways. But knowing about greenhouse gases, volcanic eruptions, fossil fuels, alternative energy sources, the sensitivity of glaciers, coral reefs, low-lying coastal regions, and the oceans might help us come to some partial solutions for saving ourselves and the biological world we depend upon.<br />
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Joseph Engemann, Kalamazoo, Michigan September 28, 2018<br />
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My thanks to Dr. Charles Heller for the loan of Hansen's book.<br />
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-29052442315622763162018-08-30T14:23:00.001-07:002018-08-31T09:01:58.780-07:00Scientific FraudThis month fraud was exposed, in numerous papers by Yoshihiro Sato, regarding clinical studies of supplements showing outstanding results in preventing skeletal fractures and/or other problems in elderly patients. The dedicated work of Alison Avenell and Mark Bollard was a major contribution toward exposing the fraud and subsequent retraction of many of the flawed studies.<br />
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Kai Kupferschmidt (2018, Tide of Lies. <i>Science</i>, 361:636-641) doe a good job of reporting the results of their efforts and the difficulty of getting scientific and/or medical journals to address the issue. The delays helped proliferate grants, studies, and publications that would never have been undertaken without the fraud. The principle author committed suicide; co-authors often had no knowledge of the fraud and very small, if any, role in the research.<br />
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Their problems of dealing with publishers of fraudulent papers made me change my mind about trying to get retractions of two papers giving invalid support to Ecdysozoa and Lophotrochozoa as legitimate animal groups. The authors did good work and were not fraudulent. They were just mistaken in relying on other papers to support some poor scientific choices.<br />
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evolutioninsights.blogspot.com/2013/05/science-screw-up-no-1.html<br />
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The above address is for my sixth blog post on May 31 of 2013. The errors in the criticized papers have probably been a major reason my views on the pogonophorans have gotten so little, if any, attention. I just checked and the sixth post noted has had 15 page views. The most popular post on this blog, about the body cavity, has had over 3930 page views since it was written in early 2015.<br />
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I was recently, in the process of trying to minimize the debris my heirs will have to deal with after I am gone, going through some accumulations packed before this blog was started. I found numerous science journal articles supporting points I was trying to make in blogs I have written. I have been writing mostly from memory and manuscripts I have written and research literature from reference files on my computer. I should blog about some of those items before I get back to the clean-up tasks.<br />
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To the kind person who commented on my October 2015 "insect speciation" post (51 page views), thank you, you made my day.<br />
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Joseph G. Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan August 30, 2018.<br />
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<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-27575283210182184362018-08-25T10:30:00.001-07:002018-08-25T10:30:43.526-07:00Book of the DecadeLightman, Alan. 2018. <i>Searching for Stars on an Island in Maine</i>, New York. Pantheon Books. 226 pages.<br />
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Delightful reading, perhaps a surprise for essays from a theoretical physicist. He seems to be trying to reconcile truths of science and the humanities, which he now teaches at MIT, in twenty well written and understandable essays.<br />
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A French cave painting from 17,000 BC provoked thinking about humans and their role in nature.<br />
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Reconciling cause and effect leads to thoughts about our inability to prove absolute truth. Absolute truths are most often claimed in theology (and the humanities?). Some philosophers of science claim falsifiability is a requirement for for all scientific concepts, laws, and theories. That does not mean they will be falsified, just that they must be capable of being tested by new hypotheses and evidence.<br />
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His fascinating blend of science and humanities topics, from the universe to subatomic particles, from the origin of the living world to the future of humans, will enlighten and hold the attention of most of us.<br />
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He finds the evolution of our species,<i> Homo sapiens</i>, is likely to lead to <i>Homo techno</i>, a blend of biological and electronic parts. I personally think it is impossible to the degree he describes, but I was wrong about us never reaching the moon.<br />
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His search (for God and/or absolute truth?) described in his exploration of Jewish, Christian, and Islamic views, as well as a ten-day Buddhist retreat in Wisconsin, and discussion of many other views, and bits from classics in the humanities, is a marvelous story well worth reading. But his scientific skepticism and application of humanities based thought leads him to a god much like mother nature.<br />
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I really like Alan Lightman, just from reading his book. It would be great to sit around the coffee table discussing all sorts of things with him. But, unfortunately, I can not sucessfully introduce him to God; he is still trying to use his skills as a scientist in the material world to prove God's existence. <br />
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All he needs to do is ask God directly, God is everywhere and always listening. He does not need to be knocked off his mount as St. Paul was, St. Paul already believed in God and was trying to serve Him in his way.<br />
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Joseph Engemann Kalamazoo, Michigan August 25, 2018<br />
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-4578902407419301372018-07-27T13:10:00.001-07:002018-07-27T13:10:34.926-07:00STEPS TO A REMARKABLE EVOLUTIONARY DISCOVERYDiscovery of the extreme age of the likely longest-lived animals on this planet was a slow process over many years. It involved the combination of many discoveries by others that has not yet been comprehended by my peers, many of whom are much smarter than I am. That the animals, the Pogonophora, are also closest living relatives of the link where the change from one major branch of the animal kingdom, the protostomes, gave rise to the other major branch of the animal kingdom, the deuterostomes, becomes understandable and obvious when all the facts are considered.<br />
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<b><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Getting ready for the discovery.</span></span></b><br />
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My early dreams as a biologist were to focus on some obscure invertebrate, that no one was interested in, so I could be the world's expert on an organism. I didn't intentionally pursue that goal in graduate school, although I realized that many important discoveries had been made by people who were not looking for their discovery.<br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;">My master's degree research was about colony growth rates of a protozoan and its lipid cytochemistry as related to culture pH. For that, Dr. Richard Fennel was my advisor at Michigan State University.</span></span><br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;">I began doctoral research at The University of Tasmania with the aid of a U.S. Fulbright Scholarship to Australia in 1956. A planned study of river pollution as indicated by invertebrates of the Derwent River was abandoned as impractical. The chair of the zoology department there, Dr. Vernon V. Hickman, suggested a poorly known isopod crustacean living in pools on top of Mount Wellington as a good object of study. It was. Dr, Eric Guiler became my mentor for the isopod study while I was at the University of Tasmania.</span></span><br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Dr. T. W. Porter became the chair of my doctoral committe at Michigan State University. On my return, the committee thought I should enlarge on the comparative studies of the Tasmanian isopod with a somewhat ecologically equivalent Michigan isopod. Both lived in temporary ponds approximately the same distance from the equator.</span></span></span></span><br />
<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><br /></span></span></span></span>
<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">The isopod study provided background for understanding principles related to adaptive changes, early embryological development and extremes of life cycle length associated with anatomy, physiology, and environment. I had no premonition that I would find it was preparation for recognizing important elements of the life cycle extremes, anatomical, and embryological adaptations of an organism with such evolutionary importance as the Pogonophora. At the time I, like most biologists, had not even heard of the Pogonophora.</span></span></span></span><br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><b> Developing an interest in Pogonophora.</b></span></span></span></span><br />
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The interest came gradually as I taught invertebrate zoology and found out about the new minor group of worms, the Pogonophora, having no mouth and no agreement on how they took in nutrients. The experts asserted that they were minor, degenerate, dead end, tube-dwellers of no evolutionary importance. I found them interesting for having so many rings on their tubes, a possible indication of greater than usual age. Most species were found at great depth, embedded in the ocean bottom.<br />
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Western Michigan University was the host of the C. C. Adam's collection of books and journal papers collected by the early ecologist. The C. C. Adams Center published a series of ecology papers and used the publication in exchange for other publications. One was <i>Sarsia</i>, a Scandinavian publication I might never have otherwise encountered. M. Webb had several research reports in the 1960's; in 1964, two of special significance were published. The first, described a rarely recovered rear portion of the worm with annelid like segmentation and setae. The second, described a clear section of tube around the worm where it had broken through and secreted fresh tube. It was similar to the upper portion of the same tube and indicated the tube was stationary in the sediment.<br />
<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><br /></span></span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Webb's above findings sent me back to studies of marine sediments that show abyssal sediments accumulate very slowly, The probable near vertical orientation of tubes and stable positioning, their length, and widespread distribution in the abyssal oceans where sediment accumulation rates are often extremely slow supported a conclusion that the worms reached great age. Cold temperatures and low food supply seemed to support the idea of very slow growth when I put a question mark at the end of the title in a short paper, "Pogonophora: the oldest living animals?" published in 1968.</span></span></span></span><br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><b>Studies suggesting verification of extreme age of pogonophorans.</b></span></span></span></span><br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Multiple studies found various indications of probable slow metabolism in the deep sea. One of the most dramatic was the very low rate of bacterial metabolism indicated by the excellent condition of food after eight months in the submarine "Alvin" before its recovery related by Jannasch <i>et al.</i> in 1971.</span></span></span></span><br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">A recent post about ocean circulation showing the thousands of year needed for polar water to reach the surface indicates very slow respiratory rates in the deep sea. It is more dramatic when you see many locations have high numbers of brittle stars in the photos illustrating Heezen and Hollister's 1971 book, <i>The Face of the Deep.</i></span></span></span></span><br />
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Questions about nutrition of pogonophorans make the absorption of nutrients from pore water in the sediments a likely answer since Southward and Southward (1982) have shown that they can absorb nutrients from water where the concentration is as low as that found in deep sea sediments.<br />
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<b>Studies suggesting the pogonophorans are the missing link.</b><br />
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I am embarrassed that I was so slow to see the pogonophorans as the link between protostomes and deuterostomes. I was quite content with the posterior segmented body section discovered by Webb and the possession of chitin as reason for their polychaete ancestry. The report of Gans and Northcutt in 1983 that developmental features of pogonohorans put them among the deuterostomes was unbelievable. My distress was short-lived when I thought it was impossible unless they were an intermediate form; all the answers seemed to pop into my head- how that would explain the inversion, the changed embryology, and the hemichordate resemblance.<br />
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There are many more features of advanced protostomes and deuterostomes made understandable by common ancestry instead of convergent evolutionary origin, The different evolution rates possible are also well illustrated by understanding the pogonophoran's evolutionary position. My isopod study, teaching a broad range of biology courses, and having to write a new section on pogonophora, provided needed background for discovery of the important evolutionary role for the supposed evolutionary dead-end, the Pogonophora.<br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Joseph G. Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan July 27, 2018</span></span></span></span><br />
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<span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><br /></span></span>Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-46235744325360811432018-07-16T18:10:00.001-07:002018-07-16T18:10:32.782-07:00THE MAJOR EVOLUTIONARY TRANSITIONAnnelid worms are ancestral to all of the advanced major phyla. Arthropods and mollusks retained annelid features as one major grouping of advanced phyla. Chordates and echinoderms are the other major grouping. The two groups share some common feature as a result of their annelid ancestries.<br />
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There are eight posts in this blog-site from 6/17/13 to 6/30/13 that are a more extended description of the basis for accepting the annelid theory of chordate origin. The annelid theory eliminates the need to (1) assume a second early origin of segmentation and/or metamerism from acoelomate protostomes, (2) explain numerous bits of molecular similarity between coelomate protostomes and deuterostomes, (3) and, with the incorporation of information about the pogonophoran bottleneck connection provided in this blog, provides a logical rationale for the embryological differences as well as the mechanism of inversion of systems in the transition of protostomes to deuterostomes.<br />
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THE ANNELID PHASE<br />
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The pogonophora are fairly well established as close relatives of some marine polychaete annelids. The fossil record provide very little evidence of events, but some annelid descendants clearly existed during the pre-Cambrian.<br />
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Step one. Tube-dwelling worms such as <i>Sabella,</i> started the rotation as they reoriented their posterior to a position in the sediments and left their plumose tentacles up in the water.<br />
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Step two. Those becoming pogonophorans had multiple changes selected by the rigor of life at constantly increasing depths as they struggled to survive asteroid bombardments in the pre-Cambrian. In particular, low metabolic rates due to abyssal pressure and temperature, tubes extending deep into the sediments for absorption of fossil nutrients, as well as retention of a blood vascular system to transfer oxygen from the water to the embedded end of the worm deep in the sediments, and loss a many non-essential features. The thinning of the eggshell enabled dropping the spiral development of annelids and the ability of eggs to develop even if some cells were lost. Loss of obvious segmentation left only a remnant of segments at the posterior to anchor the worm in its tube.<br />
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Part of step two was the reduction of the digestive system, particularly the mouth and esophagus. This allowed the later fusion of the ganglia of the head into a brain blocking the mouth formation on the old ventral side.<br />
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Step three. As asteroid caused extinctions in the surface areas of the oceans eased, progeny of the abyssal worms survived as they moved into shallow water and benefited by mouths developing where gut remnants touched epidermis on the old dorsal side. As they extending from their tube they now would use their relocated mouth to feed on particulate matter in their vicinity.<br />
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Step four. As they increased their activities they were doing it with the old dorsal side now the new ventral side. SO THE WORMS DID NOT ROLL OVER, THEY DID A BACK-FLIP as they made their transition from annelid to pre-Chordate organisms during the pre-Cambrian.<br />
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Referring to the February 27, 2015 post on "Evolution: the body cavity" may help you understand the bit about relocation of the mouth above. The March 2, 2015 post on "Abandoned theories and Libbie Hyman" has a brief discussion of the annelid theory and an associated figure.<br />
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THE IMPORTANCE OF THE REGRESSIVE POGONOPHORAN STEP<br />
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The loss of features as pogonophorans adapted to life in the deep sea were essential factors enabling the climb to the branch of the animal kingdom known as the deuterostomes, with the vertebrates members dominating life on earth. It enabled rearrangement of the head with fusion of ganglia into a brain and mouth formation on the former dorsal surface, simplified embryology of radial cleavage and delayed determination of first cells of the embryo. The loss of ability to form chitin in deuterostomes meant other structural materials became more important. Hemoglobin is the only blood pigment surviving in deuterostomes although a diversity of blood pigments are found in annelids prior to the pogonophorans.<br />
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OTHER PHYLA<br />
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There are other major and minor animal groups that are side shoots at many positions along the groups of the tree of life leading to as well as following the significant deuterostome branch. They continued, some becoming extinct, others diversifying into forms still present. One major group of arthropods, the trilobites, dominated paleozoic seas before becoming extinct. The sponges of today no longer include the group giving rise to early protostomes.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEwpYgxGUWXzQtElBqQo_ayv2ftommWJLL0gBph_aU0Yit2WIivlE3Aq1WFHq0eBjeYZpXwiYvLWHBKrw36f4WY8pR74cNKDgPBuBBZcuMlU630UtqWuprrejXVfffqUqidtaLDNUkj9Q/s1600/PAINT+TREE+%25282016_05_14+18_40_23+UTC%2529.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="648" data-original-width="648" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEwpYgxGUWXzQtElBqQo_ayv2ftommWJLL0gBph_aU0Yit2WIivlE3Aq1WFHq0eBjeYZpXwiYvLWHBKrw36f4WY8pR74cNKDgPBuBBZcuMlU630UtqWuprrejXVfffqUqidtaLDNUkj9Q/s320/PAINT+TREE+%25282016_05_14+18_40_23+UTC%2529.jpg" width="320" /></a></div>
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The above figure shows the central sequence of protostomes leading to annelids from which all above them trace their ancestry and have coelomate body cavities. The sequence follows a time sequence of origin of groups having living representatives (except for the hypothetical protonemerteans). The pogonophorans provide a transition from coelomate protostomes to the vertebrate line that clarifies the transition without the mystery of many unknown ancestral groups coming from flatworms.<br />
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Many invertebrate groups such as ctenophorans, chaetognathans, lophophorates, echinoderms, sipunculids, extinct groups, and many others are not represented in the diagram.<br />
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Joseph Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan July 16, 2018<br />
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-59279613889490403712018-05-10T08:10:00.001-07:002018-05-10T08:10:07.523-07:00EVOLUTION: AGING<b>AGING</b><br />
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Some animals have a programmed life of growth, reproduction, and death; mayflies and salmon provide commonly known examples. Others seem to continue indefinite slow growth after reaching reproductive maturity, crocodiles, some fish, and lobsters are examples. Warm blooded vertebrates generally cease growth when sexually mature because the growth zones of bones have turned into bone, so growth is limited to adding bulk - something not needed to get through the seasons of reduced food supply now that modern food production and distribution has arrived.<br />
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<b>How I Got Interested In The Physiology Of Aging</b><br />
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Along with the natural interest we have about our own life expectancy, I got a boost in my interest during my doctoral research comparing two species of isopods with greatly different life cycles. The ecological factors and adaptive strategies were understandable in explaining the differences.<br />
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Less than ten years later I was involved in incorporating new information about the pogonophora in a textbook revision. As mentioned in the previous post about Ocean Circulation, the abyssal ones had life cycles several orders of magnitude longer than terrestrial and shallow water organisms. The most likely cause was an extreme deep-sea pressure affect not likely to be a factor for air-breathing organisms.<br />
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<b>WHAT HAS HAPPENED</b><br />
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A lot has happened to about double the global average life expectancy of new-born babies in the last century. Probably the greatest factors have been modern medicine, disease control, care of newborns, care of mothers. Popular papers, magazines, and other sources of health information have been filled with information, much of it worth your time. There does not appear to be a secret food, exercise, or supplement that will answer all your health needs A balanced diet with portion control, reasonable activity, and physician recommended additions may be best in conjunction with.<br />
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<b>No smoking</b><br />
avoids many cancers, emphysema, intolerant non-smokers, and stress on the heart<br />
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<b>No, or very moderate alcoholic beverage drinking</b><br />
may help us avoid cirrhosis of the liver, deposition of excess abdominal fat, falls, accidents, and DUI citations, need to take vitamins and minerals to replace ones missed by less intake of fruits and vegetables<br />
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<b>Moderation</b><br />
in activities and intake of sugars, protein, saturated fat, and total calories - all are better than too much or not enough<br />
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<b>Social life, sleep, and mental activity</b><br />
yes, and you will probably be happier with your extra years<br />
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<b>Pick your parents</b><br />
too late, it doesn't matter as much as our environment. Superb genes will not help if we engage in unnecessary dangerous activity or ignore safety precautions. But don't lament your poor genes, passing on good behavior can be a factor more important in survival of offspring.<br />
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<b>STROKES AND HEART ATTACKS</b><br />
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and the mental deterioration we often think comes with old age may be minimized by healthy living and a love for one another. We can be in great health with only minor accumulations of cholesterol induced deposits in blood vessels, but a sudden episode of extreme exertion could cause a few clumps in blood vessels to break free and plug blood flow to areas of the brain or heart, If it hits an unused part of the brain it may be no problem. If it is small enough it may be only a short term minor problem. But don't take the chance if you have been long retired from vigorous activity. Take a smaller shovel full of snow, or don't try to keep up with speedsters; pause and enjoy the beauty of the day, and thank God that there was a time when you could do that.<br />
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<b>OTHER POSSIBLE AGING FACTORS</b><br />
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Amino acids are predominately bent in the "<i>l</i>" form and may over time be gradually converted to the "<i>d</i>" form giving rise to no, reduced, or different functionality. The process is probably gradual but may speed up due to radiation or other factors.<br />
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Telomeres that terminate the chromosomes may be reduced each cell division and reduce cell replacement in aging organisms.<br />
<br />
Accumulation of waste, or other, products in the cells may reduce or eliminate cell function. Some organisms such as some bryozoans may dedicate scattered polyps of the colony as storage sites of waste. We can't do that. But our kidneys do their best to maintain chemical balance in the blood and eliminate many wastes. However some pollutants and toxic substances accumulate over time and are poorly eliminated.<br />
<br />
Fat soluble contaminants accumulate in body fat as well as the insulating layer of some nerve cell processes of nerves and the brain. Metallic elements may be retained by combining with body proteins. The cumulative effect of such things may be intensified by weight loss from disease or dieting. Impairment of function of organisms can result from injury and scar tissue.<br />
<br />
<b>Evolution and grandparents</b><br />
<b><br /></b>
Multi-generational families are almost a thing of the past. But they were important in our evolutionary history by<br />
providing child care for young during our long childhood<br />
transferring information prior to written and electronic storage and transfer<br />
source of knowledge and wisdom aiding survival<br />
being the weak prey picked off by predators so others escape<br />
monitoring and alerting<br />
<br />
Considering genetic values that might not seem to have selective value until well after reproduction has ceased, such as factors that contribute to post-reproductive longevity, natural selection would still be effective. The genes that may not become active until late in life would be expected to be favored by natural selection as they are almost certain to be more abundant in the reproducing offspring of the ones having genes favorable to aging. It involves the same principle of group selection enabling sterile worker castes of insect to evolve features beneficial to the colony but only expressed in the sterile caste.<br />
<br />
The rapid evolution of increased brain size in humans can probably be accounted for by the benefits of greater memory capacity. Large brains of whales and elephants, although not disproportionately large as compared to humans, have a value for retention of migration histories and social behaviors beneficial to the groups survival.<br />
<br />
Joseph Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan May 10, 2018<br />
<br />
<br />
<b><br /></b>
Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-71034300830302064082018-05-03T11:27:00.000-07:002018-05-03T13:32:33.367-07:00EVOLUTION: OCEAN CIRCULATION<b>CURRENTS AND DENSITY</b><br />
<br />
Currents of major impact on the ocean are profoundly influenced by density differences due to salinity and temperature differences. The heavier water sinks and the lighter water rises. Surface currents can be wind driven. Gravity and inertia impact currents. At the interface of moving currents, or a current and still water, turbulence and mixing can be induced.<br />
<br />
Pure water is most dense at about four degrees centigrade. So progressively warmer water is usual found from near the bottom to near the surface. Salt concentration of the water may make the temperature stratification vary in other ways. For example, Mediterranean Sea water entering the Atlantic Ocean near the Straights of Gibraltar sometimes goes to an intermediate depth based on density level of the ocean of the same density, but with different temperature and salinity.<br />
<br />
Most of us are familiar with the affect of the Gulf Stream on climate in Europe, by its movement north along the western Atlantic that veers east and provides milder climates to northern Europe. A similar current affects climates in the north Pacific. While such currents catch our attention, one of greater consequence has had a profound affect on evolution as it has no doubt persisted and survived assaults by asteroids, volcanic disruptions, continental drift, and variations in solar radiation. It involves a cycle of circulation that takes ten thousand or more years to complete - from icy polar water settling to abyssal depths of temperate, sub-tropical, and tropical parts of the ocean where it slowly warms and rises until it ultimately mixes with warmer surface waters and completes the cycle by returning to polar regions via currents and evaporation and precipitation. A pause in polar ice caps can exceed the ten thousand plus year trip from abyss to sea surface.<br />
<br />
A PERSISTENT CIRCULATION PATTERN<br />
polar region temperate - sub-tropical regions<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNw7cWjlhzceCDrE9GeHO1EnQscFSYBHUagKebN8-5wQKEt6Er8PgwR-KFLG_Mv4YHZmFH0uBwojGUBZfX9bqb6M7vVXN-0qZe4beDpkS3e8SR6FV5e5xHaI50SVoQ0HgqBkvt0nO9A0E/s1600/Ocean+profile.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="564" data-original-width="696" height="259" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNw7cWjlhzceCDrE9GeHO1EnQscFSYBHUagKebN8-5wQKEt6Er8PgwR-KFLG_Mv4YHZmFH0uBwojGUBZfX9bqb6M7vVXN-0qZe4beDpkS3e8SR6FV5e5xHaI50SVoQ0HgqBkvt0nO9A0E/s320/Ocean+profile.png" width="320" /></a></div>
<br />
The visual above is not to scale but indicates the North Atlantic pattern of circulation from polar regions on the left to tropical regions on the right. Similar but variable profiles would be found in the North Pacific and Southern Ocean region of Atlantic, Pacific, and Indian Oceans. The flows would diminish and seem to disappear as they meet under tropical waters.<br />
<br />
S represents the ocean floor or sediment with a sill regulating flow from (the sometimes ice covered) Arctic Ocean water. A rise in sea level, or a subsidence of the sill can allow a greater volume of flow to the abyss of the Atlantic.<br />
<br />
C represents the cold salt water of high density that sinks to the depths of the ocean of such great volume that the warming water rises slowly, taking ten thousand or more years to mix with the warmer and less dense overlying water.<br />
<br />
M represents the oxygen minimum zone separated from W, the warm surface water, by a thinner mixing zone, the thermocline. The thermocline is identified by rapid change in temperature. A shallow thermocline may result in more light for photosynthesis penetrating beyond the mixing zone so the oxygen minimum will be somewhat deeper. Also, storms may produce sufficient turbulence at depths to make the oxygen minimum zone deeper. The extent of the oxygen minimum zone also responds to organisms living there and bacteria utilizing organic debris settling from the photosynthetic zone near the surface.<br />
<br />
W, the warm water is where oxygen is replaced by photosynthesis as well as by diffusion from the atmosphere.<br />
<br />
<b>Hurricanes</b><br />
<br />
The thickness of the thermocline is greatly affected by wave action. Calm seas may have a thermocline within a hundred meters of the surface. Hurricanes and storms can produce turbulence to make the thermocline much deeper and provide a thicker zone of warm water and heat storage that may prolong or increase subsequent storms.<br />
<br />
<b>The H.M.S. CHALLENGER EXPEDITION</b><br />
<b><br /></b>
The first major oceanographic expedition occurred from late 1873 to early 1876. One of its many accomplishments was measuring depths, temperatures, and salinity of the oceans. I had examined part of one of the fifty some volumes of its researches published later that century while I was teaching a marine biology class about a hundred years after the voyage. I don't know how many years it took me to realize that the temperature profile that I have crudely illustrated above meant that the presence of oxygen and long residence time of the deep water beneath the thermocline meant either extremely low biological activity or very few organisms.<br />
<br />
Subsequent oceanographic work has provided more complete coverage of the oceans and greater precision in measurements without changing the basic importance of the early expedition.<br />
<br />
<b>The time factor</b><br />
<br />
Sediment cores show the vast percentage of abyssal sediments accumulate very slowly. That helped me understand the extreme age of some bottom dwelling animals as indicated by their tubes position in sediments. The embedding in sediments was inferred from the rarity of finding their posterior ends in dredge samples, absence of tube rings on a posterior branch of the fork of branched tubes, and funnel-like rings on some species with rims oriented toward the anterior end (the exposed tentacle bearing ends giving rise to the common name, beard worms, of the Pogonophora).<br />
<br />
My paper describing the evidence for the beard worms extreme age - <span style="font-size: 12pt;">Engemann, Joseph
G. 1968.
Pogonophora: the oldest living animals?
<i>Pap. <st1:state w:st="on"><st1:place w:st="on">Mich.</st1:place></st1:state> Acad. Sci., Arts, and Letters</i>,
53:105-108. - was reprinted in the final chapter of - </span><span style="font-size: 12pt;">Engemann, Joseph G.,
and Robert W. Hegner. </span><span style="font-size: 12pt;">1981.</span><span style="font-size: 12pt;"> </span><span style="font-size: 12pt;"><i>Invertebrate Zoology</i>, 3</span><sup>rd</sup><span style="font-size: 12pt;"> ed.</span><span style="font-size: 12pt;"> </span><span style="font-size: 12pt;">Macmillan Publishing Co., </span><st1:state style="font-size: 12pt;" w:st="on"><st1:place w:st="on">New York</st1:place></st1:state><span style="font-size: 12pt;">.</span><span style="font-size: 12pt;">
</span><span style="font-size: 12pt;">746 pp. The extreme age concept can be found in several earlier posts of this blog.</span><br />
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<span style="font-size: 12pt;"><br /></span></div>
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<span style="font-size: 12pt;">The extreme longevity of deep sea animals is part of a circular argument that suggests the slow replacement of the cold deep water of the ocean, which in return, suggests the extreme age of the organisms there. Fortunately, other evidence is available to </span>augment the invalid circular reasoning. The most dramatic bit was discovery of unspoiled fruit and sandwich on a lunch recovered from the <i>Alvin </i>submersible research vessel many months after it sank to great depth. Several studies involving respiratory rates of deep sea organisms show greatly slowed rates compared to comparable organisms of shallow seas.</div>
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<br /></div>
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<b>Evolutionary implications</b></div>
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<b><br /></b></div>
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Some major implications are discussed in numerous past posts. Two major ones are-</div>
<div class="MsoFootnoteText">
- the error compounded in molecular phylogeny studies (especially establishment of the Ecdysozoa concept), and the unique missing link role that the pogonophorans fulfill.<br />
<br />
The permanence of the ocean stratification in tropical through temperate zones has provided stable environments where the extremely slow metabolism resulting from low temperature and immense pressure allowed those that slowly adapted to the abyssal region to survive. The pogonophorans are one of the most significant, but little known, groups. <i>Neopilina</i> is an important indicator of molluscan relationships and their annelid ancestry. Brittle stars are abundant on many areas of the ocean bottom and help us understand the selective pressures giving rise to shallow water relatives. The coelocanth fish was found at intermediate depths but is a living relative of what is otherwise known from fossils.<br />
<br />
Will the enormous area and depth protect marine life there from the assault of a constant flow of debris and chemicals we dump from ships, atmospheric contamination and polluted streams?</div>
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<span style="font-size: 12pt;"><br /></span></div>
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<span style="font-size: 12pt;">Joseph G. Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan May 3, 2018</span></div>
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<br /></div>
<br />
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-81567745496698617022018-04-28T18:32:00.001-07:002018-04-28T18:32:23.940-07:00POLAR ICEGlobal Warming<br />
<br />
Environmental changes caused by global warming seem to be more widely accepted by most, even those living in area with colder than usual weather caused by shifting oceanic currents and the anomalies of air currents and shifts in polar air masses. A recent increase in melting of shelf ice and discharge of cold water was viewed with alarm as something that might be detrimental to life in the surrounding Southern Ocean.<br />
<br />
Krill<br />
<br />
The crustaceans known as krill serve as intermediates in the food chain by feeding on algae and then being eaten by others in the food chain; even being directly consumed by the largest whales at the top of the food chain, as well as by fish and others. Some think the biomass of krill is greater than the biomass of any other animal.<br />
<br />
Krill have a life cycle of at least two years beginning with eggs released from adults near the surface of water close to the Antarctic ice-covered water. The eggs sink and hatch as they are carried by currents of near freezing sea water north from their point of origin. The eggs hatch and the larvae make their way toward somewhat warmer water near the surface that is moving toward Antarctica replacing and then becoming the cold, northward streaming deeper water. By then, two or more years later, the larvae have grown into adults that lay eggs beginning another generation that repeats the journey north in cold deep water, and back to the southern point of origin.<br />
<br />
Ice shelves<br />
<br />
The reduction of ice shelves and increasing flows of melt water from the continental margin may cause some reduction in salinity with increase in temperature. Over the centuries marine life may have experienced similar changes and developed the ability to survive such changes. Animals dependent on krill may have to adapt to new locations of krill abundance due their changing environment.<br />
<br />
Sea level changes<br />
<br />
Shelf ice floating on sea water will not change the level when it melts. If it has built up after resting on the shallow sea bottom it could raise the ocean level. If ground ice interface on land warms and contributes to glacial flow into the sea more rise would result. Since the vast amount of ice in Antarctica is under high elevations of ice it is not likely to be rapidly melted.<br />
<br />
Greenland<br />
<br />
The general consensus years ago was that the ice cover was immune to major melting. It now seems that it is a real danger, but of much less magnitude than melting Antarctic ice would represent.<br />
<br />
Joe Engemann Kalamazoo, Michigan April 28, 2018<br />
<br />
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-9828586416218858302018-04-11T14:42:00.001-07:002018-04-16T12:15:50.365-07:00EVOLUTION, AGE, AND ALZHEIMER'S<b>The Role of Evolution</b><br />
<br />
Evolution may not contribute much to solving the Alzheimer's problems although it must have been involved in the selection of genes and functional aspects responsible. Whether knowing more about the biochemistry of amyloid and tau proteins involved in the plaques and tangles diagnostic for Alzheimer's will lead to successful treatments is uncertain.<br />
<br />
Clues about the disease may come from more primitive animals with smaller and less complicated brains. Finding such clues may require greater knowledge of the process in our own brains. The pogonophorans live to extreme ages under very adverse conditions of limited food and are presumably much like the ancestors of the animal line leading to vertebrates. More recent ancestors are more likely to be of value. I personally think study of diverse human populations for their diet and health parameters may give the best clues to further research.<br />
<br />
<b>AGE</b><br />
<b><br /></b>
Because Alzheimer's and/or senile dementia increase in severity and frequency with advancing age, typically beyond the fertile years, the hereditary component thought to be about 40 percent is only indirectly subject to natural selection. Selection may differ if societies with multi-generational families are compared with societies of smaller two or three generation families. Such a comparison is not likely to be informative since the shift has been quite recent. The stress of dealing with the afflicted versus the wisdom of elders without the disease may contribute to a shift in the gene pool of such groups.<br />
<br />
Increasing age seems to enable the disease process to advance, whether by increased deposits in the brain or increased neuron death or impaired function. Life-style changes may help avert disease progress. Maintaining a social life, physical and mental activity, getting adequate rest, and good nutrition (moderation in quantities, more fruits and vegetables, and reduced animal fats). An article by Paula Spencer Scott in the April 8 (2018) edition of <i>Parade</i> is accompanied by a list of suggestions including the value of music.<br />
<br />
I'm not very good at doing the suggested changes even though I suspect several deceased relatives had the disease at death 80 or fewer years ago. I thank my spouse for my being alive with some mental function as a result of her efforts to limit my animal fat intake and increase the vegetarian portion of my diet.<br />
<br />
* * * *<br />
<b>DIETER'S CAUTION</b><br />
<b><br /></b>
Toxic substances such as DDT and other halogenated hydrocarbons polluting the food chain accumulate in animal fat deposits because they are fat soluble and poorly eliminated in urine, They may enter the blood stream in greater amounts when fats diminish due to dieting or illness. At such times the high concentration may cause or increase behavioral aberrations such as depression. Even people with little fat could experience such problems compounding illness if the little fat they had released its toxic store.<br />
* * * *<br />
<br />
It may be too early to determine if <i>Facebook</i> and <i>Twitter</i> are adequate for the social component of a healthy lifestyle. I have minimal exposure to both, but maybe if I increase my blogging it will help.<br />
<br />
An afterthought on music. The article referred to above noted singing is supposed to be a good form of music. Years ago it was common to gather around someone's piano (or other instrument) and sing together. When my father was doing physical work in his printshop he was typically whistling the same tune over and over. He was still fairly alert mentally the year he died when he was 96 years old, Maybe I will whistle more frequently. Do you think it will help?<br />
<br />
<br />
Joe Engemann Kalamazoo, Michigan April 11, 2018<br />
<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-43055335438632437382018-03-06T19:09:00.001-08:002018-03-17T13:01:11.707-07:00WMU MEDICAL SCHOOL RESEARCH<h3>
<span style="font-size: 16px;">Grant for Medical School Research</span></h3>
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<span style="font-size: 12.0pt; line-height: 107%;">Medical
research at the Dr. Homer Stryker Medical School of Western Michigan University
and at its two collaborating teaching hospitals of Borgess Health and Bronson
Healthcare will benefit from a two million dollar bequest given by Martha
Parfet's estate. She is a granddaughter
of the founder of the Upjohn Company, Dr. W. E. Upjohn. Kalamazoo has benefited greatly by the
generosity of numerous relatives and friends of both of the doctor’s families.<o:p></o:p></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;">Clinical
research will benefit from the bequest, as well as basic research using tissue
culture and cells and animals that share functions in ways more accessible than in human subjects. Such non-clinical
studies can speed, reduce cost, and sometimes simplify the discovery of things
beneficial in modern medicine.<o:p></o:p></span></div>
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<b><span style="font-size: 12.0pt; line-height: 107%;">BACTERIA</span></b><span style="font-size: 12.0pt; line-height: 107%;"> share many biochemical features of
all more advanced organisms. In
particular, they contributed greatly to understanding DNA related details. Their beneficial roles as well as the
diseases some caused will encourage continued searches for new antibiotics when
resistance to old ones develop.<o:p></o:p></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;"><br /></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;">The bacteria
of today and ourselves share some of our biochemical processes as a result of
our common ancestry over two billion years in the past. As organisms share more recent common
ancestry with us, they are expected to share more features with us although they
may lose some and gain others unique to themselves and their descendants. <o:p></o:p></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOv4xocw98_p4xwyInRYYV9SJGzw2i9fPI-TkqpB-z49C0TPA3o69eCxaAARgam0OjZad_mVcx0sAFqXnKT8j7lZQLucXNgDXA4oM8TJcj9WmrhhoCNjUNeY9ki9dI-SAqZLQrieZm6_k/s1600/branch.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="564" data-original-width="696" height="259" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOv4xocw98_p4xwyInRYYV9SJGzw2i9fPI-TkqpB-z49C0TPA3o69eCxaAARgam0OjZad_mVcx0sAFqXnKT8j7lZQLucXNgDXA4oM8TJcj9WmrhhoCNjUNeY9ki9dI-SAqZLQrieZm6_k/s320/branch.jpg" width="320" /></a></div>
<o:p></o:p><br />
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<span style="font-size: 12.0pt; line-height: 107%;">The figure
above is just to suggest what happens many times during the ancestral history
of organisms. There is no precision to
it, but the internal lines show continuity in one or both branches (multiple
branches may also occur at the same time) and it may take very many
generations that may include the beginning or end of new or old features. The short blue line on the right branch could be repeated in many times and places for numerous other extinct groups from the past.<o:p></o:p></span></div>
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<b><span style="font-size: 12.0pt; line-height: 107%;">INVERTEBRATE</span></b><span style="font-size: 12.0pt; line-height: 107%;"> animals range from protozoans and
simple sponges to complex ones, some of which, especially the giant squid,
reach large size. Invertebrates began leaving an
abundant fossil record of great diversity about 500 million years ago.<o:p></o:p></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;"><br /></span></div>
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<b><span style="font-size: 12.0pt; line-height: 107%;">VERTEBRATE </span></b><span style="font-size: 12.0pt; line-height: 107%;">animals of today share a common
ancestry with echinoderms, perhaps lophophorate animals, and a few degenerate
annelid-like worms that gave rise to early pre-vertebrate chordates that
diverged from the other advanced invertebrates (annelids, mollusks, and arthropods)
near the beginning of the Cambrian. The
following figure is intended to represent an educated guess of some of the
ancestral tree major relationships.<o:p></o:p></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;"><br /></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;">The tree of life is to graphically show the central role of the annelids leading to the two main branches of coelomate animals (protostomes left, deuterostomes right with the pogonophorans linking them to the other line) with the vertebrates upper right and the arthropods, upper left. Plants in green are are lower left, and nematodes are on the blue and red left middle main branch.</span></div>
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<b><span style="font-size: 12.0pt; line-height: 107%;">Why are organisms important in
medical research?<o:p></o:p></span></b></div>
<div class="MsoNormal">
<b><span style="font-size: 12.0pt; line-height: 107%;"><br /></span></b></div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<!--[if !supportLists]--><span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;">1.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; line-height: normal;"> </span></span><!--[endif]--><span style="font-size: 12.0pt; line-height: 107%;">Shared system features of physiology,
structure, and biochemistry are likely to be most similar when the distances
(or perhaps generations) from one group to another along the branches of the ancestral
tree of life are shortest (or fewer).<o:p></o:p></span></div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<span style="font-size: 12.0pt; line-height: 107%;"><br /></span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<!--[if !supportLists]--><span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;">2.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; line-height: normal;"> </span></span><!--[endif]--><span style="font-size: 12.0pt; line-height: 107%;">Some organisms have feature
comparable in some ways to ours, but in a more accessible or larger form. For example, the transmission of nerve
impulses was made understandable by studying the giant nerve fibers of
squids. Fruit-fly larvae have giant
chromosomes that led to some genetic discoveries.<o:p></o:p></span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<span style="font-size: 12.0pt; line-height: 107%;"><br /></span></div>
<div class="MsoListParagraphCxSpLast" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<!--[if !supportLists]--><span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;">3.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; line-height: normal;"> </span></span><!--[endif]--><span style="font-size: 12.0pt; line-height: 107%;">Basic toxicity studies of proposed
drugs can be on simple organisms after or in place of initial tissue culture or
other studies. Such tests may be much less
costly in time and/or money.<o:p></o:p></span></div>
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<b><span style="font-size: 12.0pt; line-height: 107%;">Where should medical research start?</span></b><span style="font-size: 12.0pt; line-height: 107%;"><o:p></o:p></span></div>
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<!--[if !supportLists]--><span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;">1.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; line-height: normal;"> </span></span><!--[endif]--><span style="font-size: 12.0pt; line-height: 107%;">Most likely it will start as you work with a senior medical researcher using you as an assistant performing work for
which you are trained.<o:p></o:p></span></div>
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<!--[if !supportLists]--><span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;">2.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; line-height: normal;"> </span></span><!--[endif]--><span style="font-size: 12.0pt; line-height: 107%;">A first step that should become a
habit is studying the research literature in the library, on-line, in
appropriate journals, and attending meetings of your research group. Especially, attending related research being
reported at local, state, or national conferences. Often, verbal presentations of research
include clues of value to apply in your research.<o:p></o:p></span></div>
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<b>How is evolution
important in medical research?</b><o:p></o:p></div>
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It may not always be important to you if you are a
specialist is some aspect of a research project. If you are planning research it may help you
select organisms for non-human aspects of research such as in the first list
above. Keep abreast of new developments,
even the most unlikely organisms may teach us things of value.<o:p></o:p></div>
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<span style="font-size: 12.0pt; line-height: 107%;">Although
animals greatly separated from us on the tree of life may share some identical
features with us, they are expected to have greater differences than ones that
are more recently separated. The
pogonophorans clue us in on where differences in biology are more likely to be
greater in some instances and less in others.<o:p></o:p></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;">The
pogonophorans are a bottleneck where they branch off from the annelids, losing
the spiral cleavage of the three big invertebrate groups - the annelids,
mollusks, and arthropods – as well as loss of much of the gastrointestinal
system and skeletal functions. In spite
of the latter, cartilage of the squid seems indistinguishable from vertebrate
cartilage with casual microscopic examination.<o:p></o:p></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;">Many
biochemical features survived the pogonophoran link bottleneck. Hemoglobin is the blood pigment of
vertebrates as well as some invertebrates across the pogonophoran divide. Aspects of delivery of pituitary hormones in
our endocrine system show remarkable similarities in mammals and
arthropods. Peculiar intercalated disks
of our heart muscle are also seen in some mollusks.<o:p></o:p></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;">If you find
commonalities of another organism and humans, don’t use the just stated facts
as reason to change your experimental animals.
But consider the discussion as an aide to picking new ones if
evidence warrants it. Selective evidence
was used to put nematode worms in a major cluster with arthropods when most
evidence indicated otherwise. The post -</span></div>
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<span style="font-size: 12.0pt; line-height: 107%;"> </span><a href="http://evolutioninsights.blogspot.com/2017/10/evolution-nematode-worms.html"><span style="font-size: 12.0pt; line-height: 107%;">http://evolutioninsights.blogspot.com/2017/10/evolution-nematode-worms.html</span></a><span class="MsoHyperlink"><span style="font-size: 12.0pt; line-height: 107%;"> </span></span><span style="font-size: 12.0pt; line-height: 107%;"><o:p></o:p></span></div>
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<span style="font-size: 12.0pt; line-height: 107%;">- and the post
on May 31, 2013 indicate otherwise, Ecdysozoa is not a valid related group. Both posts provide references supporting that
statement. I write this with hope
that it may be of some benefit to the researchers the grant will fund in the university
from which, twenty-two years ago, I retired. <o:p></o:p></span></div>
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<span style="font-family: "calibri" , sans-serif; font-size: 12.0pt; line-height: 107%;">Joseph Engemann
Emeritus Professor of Biology, Western Michigan University, Kalamazoo,
Michigan </span><span style="font-family: "calibri" , sans-serif; font-size: 12pt;">March 6, 2018</span>Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-47535803570917246142018-02-27T19:29:00.000-08:002018-02-27T19:29:55.995-08:00Evolution: Why God Loves You<h2>
You Are Unique</h2>
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You are the only person occupying your shoes. Take a walk through the park. Notice and appreciate the things of beauty. Hear the songs of birds, see their beautiful color and amazing flight - never smashing into a tree branch. Look for beauty in insects sipping nectar from beautiful flowers, feeding on leaves of seedlings beneath majestic trees, their forebears. There is so much more to see and appreciate.</div>
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God knows everything about God's creation, from the microscopic to the cosmic. It is all old stuff to God. But we are able to appreciate it with awe, wonder, and feelings that express our joy to God. Don't you get warm feelings when your loved ones are pleasurably moved by such things?</div>
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When you have a good story to tell, do you only tell it once? Most of us enjoy telling it over and over to new listeners. And a listener may be pleased to hear the same story from others. The excitement of each grandchild during their early childhood celebrations is always joyful.</div>
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There are billions of ways and places to have similar, but unique, experiences foreknown to God. Share them with others, but don't overdo it, they probably won't have God's infinite capacity for love and empathy.</div>
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A unique experience for me that came to mind</h4>
Our first year in a new, to us, home, we looked out a window into our back yard. A large rabbit was grazing on the grass. About a half-dozen half grown rabbits were cavorting around her. The most amazing thing was that some leap-frogged over one another several times. I had never seen that behavior before, nor have I seen it in the thirty years since. I am almost positive others have seen such behavior.<br />
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I am less sure that anyone else believes -</h4>
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- that some deep sea animals have longevity far beyond that of their shallow water relatives.</div>
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- that their environment shaped the pogonophoran transition from nervous system ventral annelid ancestors to nervous system dorsal vertebrate descendants.</div>
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- that the deep sea provided areas for the pogonophorans to survive multiple major extinction events making the preceding possible.</div>
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- the evolutionary story needs correcting where major changes were based on molecular phylogeny studies using inadequate sample sizes, as indicated in earlier posts of this blog.</div>
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Joseph Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan February 27, 2018</div>
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The opinions expressed in this blog are mine, not those of Western Michigan University; however, I am grateful for the opportunity they provided to teach courses and do research leading to my understanding of many of the topics I present. Did I answer the question why God loves you - God made you using infinite patience and the evolutionary process.</div>
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<br />Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0tag:blogger.com,1999:blog-2323644771109678846.post-52159425083025748252018-02-01T14:07:00.000-08:002018-02-09T12:21:53.952-08:00Natural Selection and CreativityMore on Wilson's Creativity<br />
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In his interesting presentation of how the human brain and many aspects of social biology came about Wilson contends that "Natural selection as grand master of evolution means that humanity was not planned by any super-intelligence, nor was it guided by any destiny beyond the consequences of our own actions." [page 103 of E. O. Wilson, 2017, <i>The Origins of Creativity</i>, Liveright, New York.]<br />
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On page 6, he had said "Scientific explanations of organic life, including human life, routinely entail both proximate and ultimate causes." He contrasts that to the humanities attempting only proximate explanations and leaving ultimate cause to various entities, without much attention to the <i>why</i> of our existance.<br />
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On page 100 he says "Because of group selection, and its obvious consequences in the evolution of human social behavior, there is reason to suppose that the better angels of our nature need not be drilled into us under the threat of divine retribution, but are instead biologically inherited." He goes on to further recognize our amazing place in nature.<br />
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What Wilson Misses<br />
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God, as the Ultimate Cause, can take the chance events of natural selection, that we see as the operative principle of evolution, and use them to produce the remarkable human species. There are obvious bits and pieces of our evolutionary development based on various pre-human ancestors. But our disproportionately large brain has the capacity for performance well beyond what most of us achieve.<br />
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Wilson sees the humanities, language, and presumably the cumulative written record, as part of the cause of the gulf between us and the rest of the natural living world. He sees the good that results. I hope he comes to see that the good is God's results.<br />
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It is very difficult, for finite beings such as ourselves, not to underestimate the power, love, and majesty of the one infinite being, God. It is very much worth the effort to try to know God better. God already knows and loves each of us more than we do ourselves. It is awesome to consider the immensity of the universe and amazing diversity of life in a drop of pond water. I don't think God needs our input on how the world should be run. But we should make more effort for properly caring for our planet.<br />
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Joe Engemann Kalamazoo, Michigan February 1, 2017Evolution Insightshttp://www.blogger.com/profile/16287417431755652361noreply@blogger.com0