A CHRISTMAS PRESENT FROM MY DAUGHTER
Naomi Shihab Nye's 2008 book, Honeybee: Poems, is a delightful book of poems and prose with observations that are very thought provoking in numerous ways. My daughter had not read the book but had heard the author at some poet's meeting where the author had read the fourth selection, "Museum".
Before I was aware of that I had commented to my spouse that it was a selection I wanted her to read even if she did not want to read the book. I had read her a couple of snippets from other entries and by the time I was one-third of the way through the book felt it was a must read for everyone who values peace, kindness, the environment, and all people.
As one who did not take the time in the 50's, 60's and 70's to tap the content of popular culture of those days it was refreshing to get a taste of it that I suspect others got in the music of the time. Pages 77 to 109 have a few entries that might distress people who do not want their status quo disrupted. So if you had some distress getting to page 77, skip to page 110. at the very least, read the last selection, "Gate A-4". I hope you read many more and find your favorites.
Joe Engemann Kalamazoo, December 30, 2016.
Honeybee: Poems by Naomi Shihab Nye is a 164 page Greenwillows Book imprint of Harper Collins Publishers. www,harpercollinschildrens.com If you read the book you will find out more about her and what stimulated many of the views I hope you will also appreciate.
Evolution 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.
Friday, December 30, 2016
Thursday, December 15, 2016
PRE-EVOLUTION ROOTS
Formation of Organic Molecules,
the Haldane-Oparin Hypothesis
The early chemical steps toward life have a good theoretical
basis. The basis is found in a 1920’s
hypothesis credited to a Russian biochemist, Alexander Oparin, and an English
biologist, J. B. S. Haldane. Each
hypothesized the first formed atmosphere lacked oxygen, but contained ammonia,
and had reducing properties. The
chemicals of the atmosphere interacted in the presence of ultra-violet light,
lightening, and volcanic heat to produce the chemical precursors of living
systems. Biologists think the precursors
accumulated in the water and somehow assembled into primitive living
systems. Such steps were necessary
because free oxygen is produced by photosynthesis and would not have existed in
abundance prior to photosynthetic organisms.
The ammonia was formed as it can be today from the effect of
lightening upon atmospheric nitrogen and water vapor. Carbon dioxide was abundant in the early
atmosphere.
An experiment in 1953 by Stanley Miller and Harold Urey in
Chicago . . . . . .used sparks in the atmospheric portions of the system to
simulate lightening. They cooled a
portion to condense water along with products in solution that were present or
produced. Analysis of the condensate
showed some amino acids and other organic compounds, most of which are
components of living systems.
Concentration of
Organic Molecules
The most important mechanism may have been concentration by evaporation
of water. Low tide could have made it a
daily event in intertidal areas. But
higher splash zones may have had longer periods of isolating pockets of water
for greater concentration.
A second mechanism is by coacervate production. The coacervates are small globules of organic
material that accumulate other organic molecules because their solubility in
each other is greater than their solubility in water. This . . . . . .could have been the route of
biological membrane formation. Membranes
. . . form naturally in systems where an abundance of the proper lipid
molecules are present. The water insoluble
ends are semi-dissolved in each other and repel the water soluble ends so a
double layered membrane forms automatically.
The third mechanism, adherence to particulate items may have been
especially prominent in pockets of water along the shore. It might be thought of as the “bathtub ring”
origin of life. It is perhaps the least
certain of mechanisms, but seems a possible explanation for aiding the origin
of some of the biochemical processes where minerals are important
components.
[The preceding is adapted
from pp. 74 and 75 of my 2009 Evolution
Insights unpublished manuscript.]
Alternative Views of
Organic Molecule Formation
An alternative view of the origin of life was proposed by a
marine biologist, Corliss, who, noting the abundance of life at deep sea vent locations where the animals surround volcanic heat and emissions produced chimneys,
suggested such sites were where it all started.
An earlier experimental observation by a scientist at a newly formed
island near Iceland showed that lava and seawater interact to produce a few
amino acids and small organic molecules.
In the early history of the earth lava/seawater interactions were
presumably more widespread and included many more shallow water locations. Such locations undoubtedly contributed to the
organic content of the original oceans but are unlikely to have been the
location where animals originated for two reasons. One, they come and go with change in lava
production and are limited in geographic extent to mostly where crustal plates meet. Two, the fossil record indicates
older forms of life seem to have originated in shallow coastal areas and
progressively over time show representatives in deeper waters.
Few accept biblical accounts of creation of life details. Certainly, God could have created the world
and its inhabitants, fossils and all, in a short time, but doing it in the billions
of years and with the details supporting the amazing story of evolution seems
like an even grander way and leaves people with the kind option of not
demanding immediate belief in an infinite deity that is all loving, kind, and
merciful.
Evolutionary
Consequences of the Haldane/Oparin Hypothesis
1. The first compounds formed, including such amino
acids as glycine and adenine, became important building blocks for living
systems. Adenosine triphosphate, the
energy currency of the cell, and the unique structure of DNA with adenine as the basis for one of its
four nucleotides of the genetic code, were important consequences.
2.
Functional values of early steps were retained
as basic, but slightly modified, characteristics seen in descendant organisms. The gradual changes leave helpful clues for tracing the evolutionary history of animals as well as plants.
3.
Photosynthesis, upon which we are so dependent
today, makes shallow seas and coastal regions the most likely place of life's origin.
4.
DNA’s early origin before the oxygen laden
atmosphere developed meant the development of the nuclear membrane probably
developed after photosynthetic bacteria.
The nuclear membrane enables DNA to operate in the part of the cell where
it experiences the cell's lowest oxygen content area most like it experienced in its
early origin.
5.
Billions of stars have planets where now or in
the past similar conditions led to production of the same basic building
blocks. Such beyond earth production makes it quite possible that
fragments of extraterrestrial bodies containing such organic compounds may have impacted earth without proving
life was present on the source planet. Planets in other galaxies, as well as in the Milky Way, have undoubtedly had similar periods with similar conditions to earth with somewhat similar evolutionary histories of life.
Joseph G. Engemann, Emeritus Professor of Biology, Western Michigan University, Kalamazoo December 15, 2016
Friday, December 9, 2016
EVOLUTION AND PHARMACEUTICALS
Evolution and Pharmaceuticals
During the course of the evolution of life on earth, species
were faced with many challenges. Over
time, a mold tailored a chemical to a point where it prevented bacteria from interfering
with its growth. Alexander Fleming noted
that inhibition of bacterial colonies on a petri dish around a fungus that
contaminated the culture. The happy
accident and his observation of the effect of penicillin led to many searches
for other fungi that might be producing other antibiotics.
We have a more versatile bacteriafighting method in our
immune system. It can even fight against
toxins, given the right circumstances.
We can induce other mammals to produce antivenoms in their serum to
combat potentially lethal snakebites when injected after a bite. Are there other marvels of nature waiting to
be discovered by our pharmaceutical industry?
Groups, especially sponges, that are attached to the sea
sediments or rocks, have an evolutionary history of over half a billion
years. Their major defense against
microorganisms such as bacteria may include physical barriers, such as mucus
secretion, but there has been a wide assortment of toxic materials, some of which
provide protection against predators and others probably against
microorganisms. It seems such knowledge
could provide a wealth of useful products.
I think the major thrust has been to look for anticancer activity in
such products.
EVOLUTION: CONTROL OF SPEED AND DIRECTION
Control or lack thereof
The hereditary changes determining the speed and
direction of evolution are not subject to control nor are they controlled by
some foreseen outcome of the process of natural selection. Many possible random events producing changes
in the DNA produce a range of possible variations in individuals. The survival value may be valuable in one
habitat, but detrimental in another.
When the habitats occur in different parts of the range, the one species
may become two or more species as accumulations of differences become great
enough that the extremes can no longer interbreed successfully with each other.
The survival or
death of a variant may be due to chance meeting with a predator. A falling rock may select traits by
eliminating those of individuals too slow to see and escape, but its selective
action would be random for traits not involving sensing its approach and
facilitating rapid evasion.
In the billion years animals have existed, and the millions of species present now and during many of those billion years, there have been uncountable selective events resulting in compounds useful for survival, and far greater numbers of events that were useless or harmful. But the harmful ones reduce the chances of their bearers surviving. The result - many millions of possible useful substances still to be discovered are out there in nature.
Speed of evolutionary change
Early in the evolutionary lineage of groups of related
organisms change was probably quite rapid as compared to groups that have not
radiated into all available habitats.
Well adapted species may change very little. This is evident in the fossil record. One of the more astounding ones is Lingula, a brachiopod living today,
whose shell is much the same, except for size, as a Pre-Cambrian fossil
brachiopod shell.
The speed of evolution of things affecting survival
can be quite rapid when there are great differences in survival value
involved. Most fish are well streamlined,
so little drag enables easy progress through the water. Birds are also streamlined, but their
streamlining is of most value at high air speeds. Natural selection maintains the streamlining
for both fish and birds.
Direction of evolutionary change
Different species of the same group may be evolving in
different directions. For example, most
mammalian groups, such as rodents, carnivores, and primates have radiated into
different sizes. Those particular
examples have mostly started from relatively small ancestors. But several vertebrate groups show the
largest species are only known from fossils.
Direction is not typically linear.
The long ancestral line from early life to us and most higher animals
went through a regression from annelids to the pogonophorans before advancing
to the groups leading to the vertebrates.
The genetic basis of the above
Most inherited characteristics of animals are
multifactorial, that is multiple locations on the DNA may affect the expression
of the characteristic. Some may have one
locus that may have an all or none effect on the expression of a
characteristic. Other characteristics
may have more complicated inheritance.
All aspects of a species are subject to evolution; besides physical and
physiological features, life style, life cycle, and other features evolve,
sometimes independently, but often in conjunction with other features. Improvement in one aspect of our physiology can have far reaching effects in many systems. Conversely, diseases are often characterized by many symptoms.
Sickle cell
anemia is an example where the substitution for one particular amino acid in a
long hemoglobin chain modifies the structure of the hemoglobin molecule. Heterozygous individuals have less expression
of the gene into the fibrous form, but their red cells have enough to provide
protection against growth of malaria parasites.
So natural selection maintains the disease in areas where malaria kills
many without the gene, and the disease kills many homozygous for the gene (i.e.,
inheriting it from both parents). But in
areas where malaria is not present, the frequency of the gene is expected to
diminish due to higher mortality of those with the disease.
Environmental control of gene expression
One of the examples of environmental control are the
two color-phases of animals in arctic and subarctic locations. In summer, several species of mammals and
birds have fur or feathers of darker colors than the white shown in the
winter. It is protective coloration for
prey species with the seasonal change, as well as enabling predators to have
greater success in getting closer to prey before they are alarmed. Apparently, the colder temperatures prevent
expression of the pigmentation genes.
I suspect my white hair is a result of lower activity
resulting in skin temperature needed to make the melanin for my long-gone
youthful dark hair; the benefit is many young people holding the door for me.
EVOLUTION AND PHARMACEUTICAL COMPANIES
Quasi-genetic control of gene expression
The existence of introns and exons suggest a possible
mechanism of graded responses of genes since so much of the DNA is not serving
as a template for RNA producing the physiological and/or structural biochemical
actions of the genome. Think how the
length of the “inactive” space between genes may moderate or accelerate
reaction to an adjacent promoter or inhibitor gene.
The enzymes acting are usually proteins with an active
site held in appropriate form by seemingly inactive parts of the molecule. The inactive parts have parts that can
undergo substitutions of minor portions that may not have much effect on
action. Hormones may have similar
flexibility.
Drug manufacturers take advantage of such flexibility
to produce new versions of medications that can then be patented to replace the
original that is going off patent. Some
molecules receiving such modification may have changed effectiveness in
unpredictable fashion with no change, bad changes, or good changes. Toxicity, solubility, and other factors make
it nearly as big a screening problem with pre-clinical and clinical testing
before marketing. But the economics of
keeping it on patent and high priced is important to them and makes it
profitable.
Designer drugs
Physical chemistry and computers have become capable
of visualizing three dimensional structures of molecules. Knowing the structure of some significant
portion of a bio-molecule makes it simpler to design chemical molecules that
will bind to the site and bring desired structure to the rest of the
molecule. There seems to be no end to
the possible applications. I doubt that
the computer will be able to do all the thinking and evaluation that a
competent research team can bring to complement the task.
PERSONAL PEEVES
A great drug company, The Upjohn Corporation, was
started by a local physician who developed the friable pill. They were an excellent employer and blessing
to the community. Several mergers later,
they are now Pfizer. Along the way research
teams were disbanded in downsizing the merged research effort. The emphasis is now on buying up small
innovative companies to stock their new-drug pipeline. I don’t know of any successes of the
computer-driven drug designing, although I am sure it has yielded some benefits
at the cost of losing possible greater benefits from the old research teams.
Now and then there are hints of and actual spin-offs
of businesses. The drug company business
types and corporate boards can now reward themselves outrageously like many
other businesses do. Shareholders,
employees, and communities suffer with the shenanigans. Short term rewards imperil future
benefits. The vast majority of executives
are honorable and hard-working, but one persuasive senior executive can do a
lot of damage in their grasp for material success. Make a big deal of the
mergers or downsizings achieved and get a big bonus in dollars or shares at
everyone else’s expense. Pfizer is still
a good company.
Joseph G. Engemann Emeritus Professor of Biology, Western Michigan University, Kalamazoo
December 9, 2016
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