pre-Cambrian survival

I never knew  -  ‘till Kalamazoo

What did I not know until Kalamazoo?  There is a tremendous amount that I didn’t know, and still don’t.  But that is probably true for most of us.  What I am talking about is some of the events related to how we evolved over the past two billion years to become the dominant species on earth.  Our knowledge of evolution is riddled with gaps and errors, even though the general story of evolution by natural selection is probably close to the truth.  The last section tells of three important ways marine species may have been able to survive the intense extended period of pre-Cambrian asteroid bombardment.

Many that believe in God reject evolution because the sequence of chance and random events are not acceptable as work of a creator conforming to their concept of God.  Many scientists, especially biologists, have found it difficult to accept God as the creator because acceptance is not compatible with their concept of the chance and randomness involved in evolution.  Both may struggle with the chaos, disasters, evil, and other bad things they see in the world and want to blame God, or see it as evidence of God’s non-existence.

Stop for a moment, and think about something in your life that seemed bad, but in retrospect you see that it helped make you who you are.  There are numerous such occasions in the evolution of life that may have been essential for evolution to take its peculiar course over the last billion years it took to produce Homo sapiens.  If that doesn’t inspire you, read on, find out how important extinction events were in the course of evolution leading to us.

THE FIRST TEN BILLION YEARS

The “Big Bang” begs a question like the one asking “is there is a noise if a tree falls in the wilderness and there is no one there to hear it?”  Astrophysicists have an answer for the projected rapid expansion from the first relative speck to the slowing expansion, formation of elementary particles, elements, and the first generation of stars.  Condensation of materials into later generations of stars (after the extinction of some early ones) was responsible for the formation of heavier elements completing the materials needed for the evolution of life on planets with favorable conditions around stars like our sun.

We don’t need to know the details of the formation of our solar system.  It was probably similar to a billion other places of the expanding universe.  Whether the protoplanetary disks around the stars formed by condensation of more diffuse matter, or from emissions or explosions from the newly formed stars, sufficient matter ended up forming planets spinning and orbiting the sun.  Some planets had sufficient gravity to retain gases in their atmosphere and retain space debris striking them.  Planets tend to collect most of the debris as well as larger objects in their orbits.  The larger objects sometimes were captured in orbit as moons or impacted the planets with varying results.  The sun, with its massive gravity, probably collected many objects, even planets, that lost speed due to some collisions and fell into the sun.

Our moon does not have seas and atmosphere like the earth, so erosion has not obscured the craters produced by impacting meteors, comets, and asteroids.  In fact, the moon may have provided some protection to us from some that would otherwise have hit the earth.  Craters are much more numerous on the far side of the moon than they are on the lava fields of the near side.

Some worry more than necessary about the danger of an asteroid causing our extinction as part of a phenomenon much like the events terminating the dinosaurs.  It is remotely possible, but the solar systems planetary arrangement suggests that a much more stable system exists than the state several billion years ago.

Where would we be without asteroids?

 The irregular structure of some asteroids and craters or “pock marks” shows they had been stuck many times.  The presence of many moons and smaller satellites around the four largest planets, all beyond Mars, suggest that some were captured as moons and perhaps the collision with potential moons and or planets may have provided the fragments (asteroids) of the asteroid belt orbiting in space between the orbits of Mars and Jupiter.

Some of those fragments provided extinction-type events in decreasing frequency as they were swept up by earth, the moon, adjacent planets and their moons.  In the beginning impacting asteroids contributed mass to the earth.  They probably sped up some of the potential chemical evolution steps in the pre-biotic earth.  Perhaps their craters filled with water to make many experiments in addition to the intertidal pools where the chemical steps leading to organic life may have started. 

How life survived asteroids

The late pre-Cambrian is thought to have experienced a long period of more intense asteroid impacts.  The abyssal sea was so great a portion of the earth’s surface layer, and the cold polar seawater flowing toward the equatorial region had high density due to temperature and salinity that allowed it to gradually replace bottom water.  The process continued taking thousands of years to have bottom water reach the surface, just as happens today.  Animals able to adapt to the abyss had such an extensive area to inhabit it enabled some to survive even the worst asteroid hits.

A second method was the selection of cysts and other survival mechanisms used as overwintering, drought resistant, and dispersal stages that can emerge from somewhat suspended animation when conditions improve.  Such stages were already being selected by the rigors of surviving dry periods in freshwater temporary ponds as well as in saltwater pools along ocean shores.  Gemmules of sponges and statoblasts of bryozoans are cystlike asexual reproductive bodies, common among freshwater species but missing in marine species, suggesting such survival mechanisms are now less valuable for marine species in their more stable environment.

A third method is direct uptake of nutrients dissolved in seawater.  The mortality of marine species may well have boosted the dissolved organic matter content of seawater following an asteroid extinction event.  It may be an important method in today’s oceans for the survival of larval stages during dispersal, especially in species providing little yolk for nutrient reserves for the larvae.  Stephens, Grover C., and Robert A. Schinske  (1961, Limnology and Oceanography, 6:175-181.)  found that in ten phyla tested only arthropods did not take up amino acids from very dilute solutions in seawater.  Manahan and Crisp (1982, American Zoologist, 22:635-646) found dissolved amino acids could be taken up by bivalves from egg to adult stages.

The pogonophora benefitted by their living in the abyss, a relatively protected location of such great extent that remnants of the population might survive.  They also benefitted from the third method of direct uptake of dissolved nutrients in sediment water.  The "degenerate" appearance of the pogonophorans is part of an evolutionary step backward that laid the groundwork for the advance of animals to today's vertebrates.

Joseph G. Engemann   Kalamazoo, Michigan    September 26, 2017

PROBABILITIES

In my second blog post (Asteroid strikes, May 11,2013) I talked about the probability of a big asteroid that strikes the earth actually hitting Kalamazoo is less than once in 100,000 over a lifetime of one hundred years.  It was over 50 million years ago that the big one that was part of the disruption leading to the extinction of dinosaurs struck the earth.  The post was to help people understand that such events are probably dropping in frequency, but were an important part of the early history of life selecting for the survival of forms such as the pogonophora to repopulate the post-strike world.

I would never have made that discovery without an almost unbelievable set of coincidences in my life that is most unlikely to be duplicated and may almost be beyond serendipitous discovery in the future if I cannot help my peers understand it.

Calculating the odds

I think it was necessary for me to study a peculiar group of crustaceans in Tasmania (the center of their distribution).  The comparison made with a Michigan species (of a different group) was instrumental for my understanding how longevity and ecology impact evolution of species.  I was the only Fulbrighter at the University of Tasmania that year and probably the only one that had ever studied crustaceans there.
The probability for this is likely less than one in 200,000,000.

The probability of that rare individual also composing a chapter for an invertebrate zoology text book and learning pertinent facts about the pogonophorans is very low.  Perhaps a few dozen biologists have done so in the United States out of several thousand.  That may be about one in a hundred.
Probability of 1 in 200,000,000 times 1 in 100 = 1 in 20,000,000,000.

The probability of being an INTP type of personality and jumping to new topics or studies before fully disseminating the knowledge or topic may be about 1 in 20.  If I had stayed on track I would have pursued things to completion and never have combined the necessary information to understand the evolutionary points I make.
Probability of 1 in 20 times 1 in 20,000,000,000 = 1 in 400,000,000,000.

The probability of having the childhood and later circumstances could be described  but are unique for everyone, even identical twins.  Some of those events may be described later, but it makes me almost certain the chance of someone doing the same is a practical impossibility.  We share a lot, but you will be the only you, just like me.

Joe Engemann     Kalamazoo, Michigan    February 22, 2017

THE MOON: ORIGIN, IMPACT ON US, AND DEMISE

WHY THE MOON?

Two days ago I was watching an episode of How the Universe Works, on the Science Channel.  Its original air date was 8/18/2015.  The title of the episode was "Secret History of the Moon".  There was a considerable amount of new information for me, especially the evidence of much more water, volcanic activity and resulting lava tubes that may possibly be used for establishing self sustaining colonies as a base of more distance space exploration.

It was somewhat oversold for its emphasis on possible dramatic explanations of its origin and ultimate demise taking us with it.  The end involves the expansion of the Sun billions of years from now.  Also, the hypothesis of a twin star of the Sun circling with us in a pattern that will provoke peaks of comets and meteors from the Oort Cloud beyond the known planets to endanger us with a cycle of recurrences every 20 some millions of years, is very speculative.  Such a periodic event would be much more regular than past extinction peaks indicate.

MOON ORIGIN

 It is reasonable that the moon's origin was part of the condensation of the early protoplanetary disk around the Sun and aggregation of particles.  The process would continue with greater efficiency, due to gravity increasing with mass, until the results were established in orbits around the sun as they are today.  Probably there were multiple small moons during an early phase, but the compactness of orbits close to the Sun made them more likely to collide and grow into the single moon the earth has.  The dozens of moons of Jupiter and Saturn and more distant planets shows moon accretion is probably a common process.

My contention that the asteroid belt between Jupiter and Mars seems consistent with the possible collision of two planets producing the fragments of the asteroid belt.  The fragments have been mostly swept from orbits of nearby planets - Jupiter, Mars, Earth and its moon.  This origin is consistent with the outer layers of moon and Earth having the same geology that has, probably erroneously, been considered evidence of the moon resulting from a collision with earth causing the similarity.

THE MOON'S IMPACT ON US AND EVOLUTION

I've heard or read that there is a peak of violent acts resulting in increased emergency room visits during the days around the Full Moon.  The word lunatic gets its origin from the phenomenon.  There is no bad magic about it, probably just an impact of poor sleeping with the greater night-time light.  But the approximate 28 days of the lunar cycle has probably selected the duration found in menstrual cycles.  The cycles of growth some marine mollusks show in their shells can reflect the lunar cycle.  They can also show the daily growth and seasonal growth so we know that near the beginning of the fossil record there were more days in a year before the tidal tug of moon on earth and/or a slowing due to space debris accretion made the days longer, but the year shorter in terms of number of days.

The craters on the moon seem better evidence of asteroid impacts than of volcanoes.  But the side facing us has the clearest evidence of volcanic activity.  The smaller size of the moon, compared to the earth, is consistent with an earlier cooling and lessening of volcanic activity.  The earth's greater size means it would collect more space debris (asteroids etc.) than the moon.  A Pre-Cambrian peak of that type of activity was probably a major selective force during extinction peaks shaping the pogonophoran link as noted in the post [ http://evolutioninsights.blogspot.com/2013/06/evolution_28.html ].

The post [ http://evolutioninsights.blogspot.com/2013/05/asteroid-strikes.html ] was my second post on this blog and enlarges on the comments of the evolutionary impact of asteroids and the deep sea as a refugium enabling the evolutionary events leading to the pogonophoran link of deuterostomes to protostomes.

If you think the collision of two planets causing the asteroid belt is improbable, check the graded spacing of planets and the gap between Mars and Jupiter.

Joseph G. Engemann  Kalamazoo, Michigan    January 7, 2016