Thinking 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.
THE BODY CAVITY
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.
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.
THE DEEP SEA
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.
THE POGONOPHORA
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.
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.
REGRESSIVE EVOLUTION
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.
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.
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.
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.
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.
MOLECULAR SIMILARITIES
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.
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.
DO NOT FORGET
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.
Joseph G. Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo, Michigan February 12, 2019 (Happy 128th birthday, Dad)
Showing posts with label the body cavity. Show all posts
Showing posts with label the body cavity. Show all posts
Tuesday, February 12, 2019
Monday, November 9, 2015
THE BEGINNING OF THE END?
MORTALITY
The end of life is ever more close. But it isn't of great concern when you truly believe you go on in a better way in the hereafter. In about thirteen years I will be 100. I keep getting warnings the end is near.
Eight years ago I had a case of shingles in the right trigeminal nerve region. Fortunately, my eye escaped the damage it often causes. Blood work at the time showed some immune deficiencies and a marrow sample indicated I had the same disease that Carl Sagan had died from about six months after a successful bone marrow transplant.
One or two shots a week at the local cancer/blood diseases center have maintained neutrophils at low levels, but high enough that they seem to prevent infections. But an accompanying low level of platelets means a minor accident could be fatal- hence my internist son wants me to promise not to drive when schools are closed and roads are icy.
A FINAL POST
I've given some thought to a final post so a daughter could click on the publish button after I am gone. Because of the mix of topics I'd like to cover, I probably should write separate ones. If I mention God, half my readers are likely to tune out. If I mention evolution, the other half are likely to tune out. I have already tried to discuss why the two concepts are not mutually exclusive. It appears to me that some teachers in Europe and Asia have focused on a few evolution posts to have classes access them; it is just my guess based on peaks in page views.
POPULAR EVOLUTION POSTS
A February 27, 2015 post, on Evolution: the body cavity, covers a topic presumably given very little attention although it is important in understanding physiology and evolution. The content could help you understand why I think the biggest gap in the origin of coelomate animals can be filled by an ancestor of nemerteans.
The May 2, 2014 post, on Evolution of Macromolecules, when applied to cell physiology, can help one understand the natural selection biochemical features of cells had as most of the important underpinnings developing before the origin of multicellularity.
The April 8, 2015 post, Cnidaria: nematocyst origin, provoked renewed interest in the July 19, 2013 post on Acoelomate evolution, 2, cnidarians. They should be helpful in understanding the sponge-cnidarian-flatworm sequence of early evolution that had to be completed in the Pre-Cambrian before the protonemertean-polychaete-pogonophoran sequence led to hemichordates, then chordates.
OVERLOOKED POSTS OF IMPORTANCE
In order to understand the major errors infecting current evolutionary theory attempting to determine the "Tree of Life", the errors made in proposing the Ecdysozoa and Lophotrochozoa need to be seen. The post of May 31, 2013, Science Screw-Up No. 1 points out the errors that should have been seen by reviewers and stopped the publications involved. There are many other posts that provide a more rational answer to explain the "Tree of Life". It is necessary to understand the ecology of the deep sea to see how the pogonophorans have answered many important unasked questions about evolution.
ECLECTIC OR CHAOTIC?
My interests had jumped around in animals of interest over the years, as well as thinking of moon origin and the early environment on earth, continental drift, and unfortunately, or fortunately, not in a well-planned way. Without my chaotic background, I doubt I would have arrived at the role of pogonophorans and extreme longevity answering major questions of evolution. I accumulated a stack of mostly unpublished papers that I looked at and thought I should assemble them in a book. I think I picked the title, "Animal Evolution: A Serial Symposium" to accommodate my eclectic collection. That was almost thirty years ago when I started printing it out on a dot-matrix printer. The files saved on floppies, hard disks, and tape never got fully transferred to CDs and thumb drives before the old hard drives were corrupted; probably a good thing they are not swamping me with redundant data.
When I retired nineteen years ago, I was going to write the book that turned out to be "Evolution Insights", my 2010 unpublished manuscript. That might never have been done if I hadn't had the health problems noted above warning me time was limited. This blog was conceived of when it was apparent publishers were not looking for such books from new (though ancient) authors in 2010. Again golf and other things became distractions until other health problems jarred me in to getting a blog going. So I thank Google for their support of this blog and hope that it will survive my demise - whether tomorrow or ten years from now. This is not meant to be morbid, but you start to think about such things when you return from a memorial service for a WMU colleague first met about 51 years ago.
So while I work on my final post I will probably continue posting.
Joseph G. Engemann Kalamazoo, Michigan November 9, 2015
The end of life is ever more close. But it isn't of great concern when you truly believe you go on in a better way in the hereafter. In about thirteen years I will be 100. I keep getting warnings the end is near.
Eight years ago I had a case of shingles in the right trigeminal nerve region. Fortunately, my eye escaped the damage it often causes. Blood work at the time showed some immune deficiencies and a marrow sample indicated I had the same disease that Carl Sagan had died from about six months after a successful bone marrow transplant.
One or two shots a week at the local cancer/blood diseases center have maintained neutrophils at low levels, but high enough that they seem to prevent infections. But an accompanying low level of platelets means a minor accident could be fatal- hence my internist son wants me to promise not to drive when schools are closed and roads are icy.
A FINAL POST
I've given some thought to a final post so a daughter could click on the publish button after I am gone. Because of the mix of topics I'd like to cover, I probably should write separate ones. If I mention God, half my readers are likely to tune out. If I mention evolution, the other half are likely to tune out. I have already tried to discuss why the two concepts are not mutually exclusive. It appears to me that some teachers in Europe and Asia have focused on a few evolution posts to have classes access them; it is just my guess based on peaks in page views.
POPULAR EVOLUTION POSTS
A February 27, 2015 post, on Evolution: the body cavity, covers a topic presumably given very little attention although it is important in understanding physiology and evolution. The content could help you understand why I think the biggest gap in the origin of coelomate animals can be filled by an ancestor of nemerteans.
The May 2, 2014 post, on Evolution of Macromolecules, when applied to cell physiology, can help one understand the natural selection biochemical features of cells had as most of the important underpinnings developing before the origin of multicellularity.
The April 8, 2015 post, Cnidaria: nematocyst origin, provoked renewed interest in the July 19, 2013 post on Acoelomate evolution, 2, cnidarians. They should be helpful in understanding the sponge-cnidarian-flatworm sequence of early evolution that had to be completed in the Pre-Cambrian before the protonemertean-polychaete-pogonophoran sequence led to hemichordates, then chordates.
OVERLOOKED POSTS OF IMPORTANCE
In order to understand the major errors infecting current evolutionary theory attempting to determine the "Tree of Life", the errors made in proposing the Ecdysozoa and Lophotrochozoa need to be seen. The post of May 31, 2013, Science Screw-Up No. 1 points out the errors that should have been seen by reviewers and stopped the publications involved. There are many other posts that provide a more rational answer to explain the "Tree of Life". It is necessary to understand the ecology of the deep sea to see how the pogonophorans have answered many important unasked questions about evolution.
ECLECTIC OR CHAOTIC?
My interests had jumped around in animals of interest over the years, as well as thinking of moon origin and the early environment on earth, continental drift, and unfortunately, or fortunately, not in a well-planned way. Without my chaotic background, I doubt I would have arrived at the role of pogonophorans and extreme longevity answering major questions of evolution. I accumulated a stack of mostly unpublished papers that I looked at and thought I should assemble them in a book. I think I picked the title, "Animal Evolution: A Serial Symposium" to accommodate my eclectic collection. That was almost thirty years ago when I started printing it out on a dot-matrix printer. The files saved on floppies, hard disks, and tape never got fully transferred to CDs and thumb drives before the old hard drives were corrupted; probably a good thing they are not swamping me with redundant data.
When I retired nineteen years ago, I was going to write the book that turned out to be "Evolution Insights", my 2010 unpublished manuscript. That might never have been done if I hadn't had the health problems noted above warning me time was limited. This blog was conceived of when it was apparent publishers were not looking for such books from new (though ancient) authors in 2010. Again golf and other things became distractions until other health problems jarred me in to getting a blog going. So I thank Google for their support of this blog and hope that it will survive my demise - whether tomorrow or ten years from now. This is not meant to be morbid, but you start to think about such things when you return from a memorial service for a WMU colleague first met about 51 years ago.
So while I work on my final post I will probably continue posting.
Joseph G. Engemann Kalamazoo, Michigan November 9, 2015
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