Explaining Evolution to deprogram creationist Propaganda
A Layman's explanation of Evolutionary Theory
This essay was originally posted on July 24th 2000 in response to a Biblical creationist posting on Usenet who misunderstood evolutionary theory so badly that he used the following example in an attempt to refute it:
"If you put automobile parts in a box and shake it up for a trillion years, you will not get an automobile".
Apparently, he believed biological evolution to be no more structured than what could be accomplished in a Quisinart.
I have since heard other creationists define evolution as a collection of single cells that suddenly, intentionally, and purposefully amassed themselves directly into a human being while other separate cell groups independently evolved into reptiles, birds, fish, etc. Another creationist also described a single individual fish suddenly growing legs and walking within one lifetime. Another demanded that if evolution were true, why didn't horses sprout wings to escape predators?
A collection of statements indicating the status of evolutionary misunderstanding in the United States can be found here: http://www.onthenet.com.au/~stear/cre_is_not_the_alt_to_evo.htm
Gallup and other recent national polls have concluded that approximately half of all Americans believe in Biblical creationism and consider evolution to be counter to that belief, but that absolutely all of the criticisms of evolution thus far stem from a combination of ignorance and misinformation. In some cases, the ignorance is willful and the misinformation is intentional and deliberate misrepresentation. If such is the case and half of America has been this badly deceived, then I believe that an easily accessible layman's explanation of Evolutionary Theory is desperately needed. Especially when creationists hold the majority of politcal offices granting them the influence to retard our science eduaction even further than it already is.
I am flatly stunned at the amount of misrepresentation that goes on in creationist circles. I am also impressed at attempts to refute such a simple eventual process by referring to an imagined intent or purpose on the part of developing cells when there is none. And especially by attempts to discredit the science by illusory arguments such as the inapplicable second law of Thermodynamics and transient definitions of "information", "complexity", and "kind", none of which can be properly defined and so do not relate to genetic biology in the context used.
Creationists also like to call upon Occam's razor, which only appears to make sense if you already believe in false pretenses and purported theological discoveries that never really happened AND only if you have no understanding of evolution whatsoever other than the ridiculously inaccurate parodies and "strawmen" accusations repeated by fundamentalist propaganda mills like: Answers In Genesis, the Creation Research Society, and the Institute for Creation Research. All of which have been shown to intentionally promote misinformation and on some occasions, their leaders have falsified their credentials and knowingly lied on public record.
Forget everything they ever told you and do some independent research on your own.
Now for the basic primer for our evolutionary history:
Has nothing to do with evolution which is the process by which generations of organisms adapt variances from parent organisms. No parent organism = no evolution. How the first living organisms got their start is still in question. Its only relevance here is that origins of simple replicative proteins such as viruses over a billion years ago is not covered by any religion because religious myths were concocted in ignorance of them and in ignorance of the common descent of all other organisms to them. They could have been spontaneously vitalized, seeded by aliens, left by time travelers, or created by God. However the first organism got here doesn't matter to evolution. It is a separate subject.
Compare evolution to a string of dominoes. We know that one falling domino will knock down the next one and so on. That's how it is with evolution. Each species is defined by its predecessors and will in turn further define future generations. What caused the first living organism is a similar question as what knocked down the first domino. It could have been toppled by natural means, or it could have been an intelligent entity acting either accidentally or with intent of design. Whatever the catalyst to start the first domino falling, it doesn't change the fact that it will effect all other dominos after it just as it was effected by all other dominos before it.
Biological evolution is not dependant upon any theory of astronomy either. That would be like asking where the table came from that the dominoes are on. Whatever that is or wherever it came from doesn't change the fact that they are knocking each other down in succession. Nor does evolution specifically plead for an atheist resignation as it is an ingenious process. If it were the result of intelligent design, that architect should be quite proud of it.
Creationists like to argue having never found an expected "missing link" between humans and prehistoric apes. In fact, humans are still basically "apes" even now and there has been no significant "missing link" in that lineage since 1974. What surprises me is that there never was much of a gap to close with that creature anyway, especially considering Rudy Zallinger 's illustration of the rather fluid transition from pliopithicus and proconsul through Australopithecus, Homo Habilus, and modern man some twenty (no longer missing) links later. Exposed frauds such as Piltdown man and Nebraska man are not included in that lineage and never were.
I found much greater gaps elsewhere that Creationists were never clever enough to think of, such as the gap between single-cellular and multi-cellular organisms, transitional species betwixt reptiles and mammals, and the transition between saurischians and ornithiscians in the dinosaurs. With a bit of research, I have since discovered all three.
In the beginning
Contrary to most creation stories, there was a point when there were no liquid seas. Hence there were no waters "in the beginning". The land was here first.
The single-celled to multi-cellular transition
The most profound evolutionary gap in the entire line was closed by a microscopic worm that still exists today. The worm travels as a worm and segments like a worm and even eats through osmosis like a worm, but with one
important difference; when it eats, it dissolves into a mass of individual single celled amoebic forms who in turn also eat by osmosis. Then the party loads back into the communal animal it arrived as. On a microscopic scale, this is similar to a school of fish acting as a group. All of these type amoebae are simply following chemical stimulus to eat and unify and continue on. The specialization of interior cells is no different than similarly functioning individuals in an ant colony where workers bring in food and materials to the perpetually sequestered queen and nurses, farmers, etc. That arrangement works better and it is an easy step to take to specialize the internal cells so eventually, some transitional worms would be transitional no more. Such I suspect would be the beginnings of multi-cellular life on this planet.
The very first tentative multi-cellular life-forms were originally capable of any configuration, but not all of them were functional as reproductive creatures capable of surviving through numerous generations. The Cambrian explosion was the period in which all of the five kingdoms of life that still exist originally developed, but that so-called explosion began much earlier, in the Vendian period, 650-544 mya. None of the creatures yet uncovered from the fossils of that time exist today and all are so bizarre as to defy classification. http://www.ucmp.berkeley.edu/vendian/critters.html
Another creature that no longer exists today were the pikaia that developed later during the Cambrian. It looked similar to worms pretending to be very tiny sharks. The only skeleton they possessed was their teeth, (like modern sharks) but they also had notochords that classify them as the earliest known Chordates. http://www.gpc.peachnet.edu/~pgore/geology/historical_lab/evolutionofvertebrates.htm
The incredibly slow evolution of cartilaginous fishes and bony fishes apart from mollusks and other sea forms from the pikaia and similar creatures should be fairly obvious, so I'll move on to exemplify another important milestone.
From sea to land
Now that the ocean is chocked full of life, some of it has been crowded onto and trapped on the shores of the still desolate land. During the Devonian period, 408-360 mya, plants began to grow very near the shorelines and those who could not survive at low tide didn't continue to grow there. Those that could survive in the dry environment could also seed the land. Crabs and other crustaceans could also leave the water because they subsist with neither gills nor internal lungs. Theirs is usually an external frond that remains clearly visible on the underside of modern scorpions. Our modern pill-bug or roly-poly is actually the only completely terrestrial true crustaceans and they actually use their gills fronds to breathe air. Permian scorpions were noticeably different than their terrestrial descendants and were much larger, reaching up to as much as 5' long on rare occasions. But from them came smaller more agile forms that would for a time be the largest dry land carnivores on Earth. Roaches could withstand such extremes as freezing temperatures and radiation as could the scorpions who hunted them. It is not surprising then, that these creatures would be so successful in the desolate alien landscape above the waves. Nor is it surprisingly that they have changed so little in all this time.
Now come fish of a new variety. The shallows and their tides have trapped many of them and all those trapped have died until one with a distention in its spinal buoyancy bladder survived. All fish have a bladder near the spine that stores air for buoyancy. These just happen to process oxygen at the same time, greatly extending the fish's survivability on land. Modern fish use this bladder to breathe air when the water becomes too warm or stagnant to maintain a comfortable level of oxygen, but in most modern fish, it is not developed well enough to breathe independent of the gills.
No fish can stay out of water very long even with primitive lungs, so they must find a way to flop back to the shallows. As the tides wash in and out over millions of years only the most capable of fish at breathing, flopping, and undulating would survive. Eventually we had today's four-legged lungfish who sleeps in a cocoon in the dryness of the desert and walking catfish capable of walking for several miles from lake to lake. If a fish was born with only slightly larger or more efficient lungs than his siblings, then he would live longer and go further and those larger lungs would be bequeathed to his offspring.
Similarly, having stronger fins meant being able to walk further without falling over. Eventually there were (and are) lobe-finned land-walking fish with all of the bony segments already in place that would become the tibia, fibula and carples of true legs. They had lungs to breath air, but were still utterly dependant on the water because they were still subject to dehydration, just like the salamanders that followed them.
The Darwin fish
Among the lobe finned fish of 400 million years ago was Panderichthys. Like the lungfish, this six-footer also had lungs and nostrils to breath air and it too lacked its anal and dorsal fins, Panderichthys' tail was also like that of a lungfish in that it did not end flukes off the tip. Its tail consisted of rays above and below the vertebrae and looked similar to the tail of a salamander. It was a good swimmer, but likely cruised the sea floor or sat on the bottom motionless on its four legs awaiting unsuspecting passerby. It would appear that Panderichthys and other lungfish are closely related. The only significant difference between the two is that the lungfish has no fins on its legs at all.
Following Panderichthys by a few million years was Sauripteris who's fins were no longer configured in true rays like other fish. Sauripteris's was physically identical to Panderichthys except for the presence of eight bony fingers instead of the usual rays found in all other bony fish, (except lungfish). Another as-yet unnamed transitional species was recently discovered in Pennsylvania. Permian fossils are especially rare compared to more recent eras and many of those recovered are known only from fragments. One of these is a lithographic print of a complete fin showing eight partially formed fingers developing amongst a few remaining rays.
Unnamed fish developing "fingers" amid its rays.
Sauripteris was followed by Liviana and then Acanthostega, both heralded as the most "transitional" of all species. Acanthostega was similar in appearance to Sauripteris except for the four appendages upon which it scuttled along. Acanthostega took Sauripteris' lead and added the beginnings of jointed elbows in the bones of its arms. The rear fins were mounted on slightly longer legs that were in turn braced to a stronger pelvic girdle than any previous fish had. It was still ungainly out of the water and could hardly survive long without the supportive buoyancy, but it could walk along the sea floor as well as any latter amphibian could walk on land. In fact, its "fins" were no longer just that. They had become webbed feet with eight toes on the front and seven on the rear. The rear feet give an indication of how the first tetrapods eventually reduced the number of toes down to five per foot. Three of Acanthastega's seven rear toes are compressed together looking rather like the thumb of a five fingered hand. Despite the fact that Acanthostega still had the complete internal gills of all other bony fish, it also had a strong set of lungs. It was at once both a fish and an amphibian, in much the same way as archaeopteryx was both a dinosaur and a bird.
Archaeopteryx lithographica 150mya
Acanthostega's successor, Ichthyostega was also similar in appearance, but lacked the internal gills of all of its forerunners. It also lacked the dermal bones that supported the tail fin, but the fin itself remained, albeit at a smaller size. Ichthyostega could leave the water to venture out onto the land, but it was still ungainly and obviously preferred to remain in the water for most of its life. It would have behaved very similar to today's axolotl in that respect. Both animals are so closely related to bottom dwelling fish as to be difficult to discern them. In fact, two species of modern lungfish have been categorized as amphibians where the others are still considered fish.
A common perception is that scales would divide amphibians from both their fishy ancestors and their reptilian descendants, but this is a misperception. Fish scales are made of dermal bone and are set above the skin. The scales of a reptile are made of carotene and are sub-dermal, allowing the skin to be shed without losing a single scale in the process. There are even amphibians that still exist today that have residual bony scales in their skins. These include the caelilians, which strongly resemble eels. The hardened nodules present on newts are likely to have developed harder deposits that could eventually become reptilian scales after a few generations of "weathering".
Fish with lungs (including amphibian "fish"
Observe an axolotl (or mud-puppy). In it's youth, it is essentially a walking catfish. It has the eyes, mouth, skin, internal organs and even the habits of a catfish. It even walks the same way, more dependant on its side-to-side body motion than on its legs. It too has lungs as well as gills, but it's gills are distended (inside out). Eventually, as it migrates across the land, it no longer uses its gills and they shrink away. If gills are dysfunctional after a certain time, it doesn't matter, so the genes for sub-standard gills eventually find their way into the gene pool. Adult axolotls, lose their gills along with the body-length fish fin on their tail and become primarily land lubbers. Axolotls repeat their evolutionary lineage in their development just as the embryos of other animals do in the womb or ovum. Bird embryos have teeth and so do baleen whales. Snakes fetus have legs complete with toes, etc. The young hoatzin is a bird that retains fingered claws until adulthood. And human embryos at early stages even have tails.
The eggs of amphibians are dependant upon the water, but are laid along the shore to provide the most light and warmth (and because the parents can no longer breath water). Just as a peeled grape will develop a kind of skin
when it is left to the air, so do the amphibian eggs, usually at the cost of the contents. After millions more years, some lucky generation had a kind of skin pre-installed that withstood accidental exposures to dry air. Obviously these survived to pass the benefit of that mutation on. After a zillion or so generations, subsequent offspring that had tougher and harder skins on their eggs also passed on those genes along with the gene for tougher and harder skin on the body itself as well as chitinous claws for terrestrial traction. Where the salamanders were too sensitive to survive, the genes that beget the reptile allowed these amniotes independence of the sea to conquer the land. From there, they began to diverge into numerous species that subsequently diverged into numerous subdivisions which eventually created enough distinction to define differences in taxa well beyond speciation. The original amniotes diverged into anapsids and synapsids.
Interestingly, one terrible mutation that occurred at about this time remains our cross to bear today, cellular senescence or "aging". Turtles, amphibians and fish don't suffer the ravages of old-age. They eventually succumb to injury, predation, or disease, but they never grow old. All of the descendants of the diapsids and synapsids do. Archosaurs such as crocodilians to a lesser degree probably because their lineage diverged independently so very long ago. All modern reptiles, birds, and mammals become decrepit and die of their old age.
From the anapsids came the diapsids or (true reptiles) Archosauria: Crocodilians, dinosaurs; and from them, birds.
Lepidosauria: sphenodons, lizards; and from them, snakes. Of the original anapsids, only turtles survive to the present day. Synapsids diverged into pelycosaurs (now all extinct) and therapsids which represented varying degrees of development from reptilian forms to more and more mammalian traits. From them came the cynodonts, a distinctly transitional order between "reptiles" and "mammals".
Eventually, Monotremes (egg-laying proto-mammals: platypus, echidna) would evolve and diverge again between the Multituberculates (now all extinct), the Marsupials (Pouch-bearing mammals: kangaroo, opossum, etc) and finally, placental mammals such as ourselves. Placental animals still ovulate, but like some diapsid reptiles, the young emerge from the embryo partially developed while still inside the "mother". If an egg's incubation period is reduced, so is the risk of predation in the mother's absence. If the mother gestates long enough to skip that step altogether, the chances of protected survival increases exponentially, thus these traits too are continued in subsequent generations throughout time.
So here you have an extremely brief analogy of the longest period of life from abiogenesis through the Mesozoic era, illustrating how typical propensities, environmental stresses, and natural selection eventually evolved simple replicative proteins into lizards and mammals entirely without the necessity of a designer and using only subtle adaptations over an incredibly long sequence of continuously repeating generations. There is neither order nor chaos, there is only what works and what doesn't and what works generally survives, if only long enough to breed and beget another generation.
If you absolutely must rationalize a divine involvement in all of this, I have a suggestion for you:
If we knew the walking catfish only from fossils,
we'd never know what it could do.
If we knew the lungfish only from fossils,
we'd never know it had lungs.
The external gills of the axolotl would never have fossilized and so we'd
never know the truth of it either.
The same is true of the Amoebic worm.
Maybe there is a reason these animals continue to exist.
Maybe it was just so that we will know the truth.
As for what is found in the fossil record, remember
Psalms 85:11 "Truth shall spring out of the Earth".
Any questions or disputes are welcomed by this author, but your best source of relatively unbiased information would be to participate in the usenet discussion group, Talk.Origins.