Pro-Evolution II: What evolution DOES mean


Here are some of the things evolution DOES mean:

  • In its most advanced form, the modern evolutionary synthesis has been accepted by all mainstream scientists.  This modern evolutionary synthesis, briefly, contends that life on earth was not created all at once.  It developed by a series of minute changes
    over a long time.  For a long time, scientists, including Charles Darwin himself, couldn’t figure out how those changes could keep from being swamped by a larger population.  For instance, if one fish was born with fins that helped it climb up on land to eat plants that other fishes couldn’t reach, it would have an evolutionary advantage over those other fish.  It could eat more and get stronger.  It could have more offspring that would also be likely to have those leg-like fins.
    The problem for early evolution scientists was the idea that the tendency to have leg-like fins would be watered down by mating with fish that had fin-like fins.  Even if a fish had an evolutionary advantage with leg-like fins, its offspring would blend the
    characteristic of leg-like fins with the characteristic of fin-like fins.  Over time, the tendency to have advantageous leg-like fins would be swamped by the majority of fishes’ fin-like fins.  The solution to this dilemma came to scientists by the 1930s.  Scientists realized that life on earth doesn’t work that way.  Instead, the offspring of a fish with leg-like fins with a fish with fin-like fins would carry the genetic tendency to be born with leg-like fins, even if the fish itself had fin-like fins.  You may remember something like this from high-school biology. The idea was a little older, discovered in the 1800s by a monk named Gregor Mendel.  Mendel observed pea plants and noticed that there was a regularity to their characteristics.  About one in every four
    tall pea plants, for instance, was short.
    Mendel realized that the short characteristic was carried recessively even in the tall pea plants.  When two tall pea plants with that recessive characteristic produced new pea plants, every fourth offspring would end up short.  How would this work with our fish with leg-like fins?  The genetic tendency to have leg-like fins would be latent in fish even with fin-like fins.  That is, they would have the genes to grow leg-like fins, but most of their offspring would have fin-like fins.  Every once in a while, a fish with leg-like fins would be born.  When the circumstances changed and these leg-like fins became an advantage, fish with leg-like fins would have more offspring more often.  Their offspring would carry the genetic tendency to be born with leg-like fins.
    Over time, if there was more food accessible out of the water, and if food became scarcer and scarcer below water, those fish born with leg-like fins would prosper, and find more mates also with that characteristic.  Not soon, but over time, a new species of
    fish with leg-like fins would evolve.
  • Some of the most convincing biological arguments for evolution come from what scientists call ontogeny and homology.  Ontogeny means roughly the way animals develop.  Some steps of that development only make sense in an evolutionary framework.
    For instance, embryonic whales grow legs for a stage.  Why?  Especially vital for our argument here, why would whales go through a developmental stage with proto-legs if God had simply created them in their current form?  It makes no sense.  It would be an example of the kind of evidence that God would have had to have left behind in order to fool humans
    into thinking life evolved.  Because those embryonic legs make perfect sense in evolutionary perspective.  For a time, whales had been land-dwelling mammals.  They developed their ability to survive and thrive in water as an evolutionary niche developed for them.  Their embryonic history demonstrates that path.  Although early evolutionists such as Ernst Haeckel overstated their case for the importance of ontogeny as a path of evolutionary development in all animals, in some cases it still points to an
    evolutionary origin for different forms of life.
  • Scientists also note powerful homologies among very different kinds of animals.  By this they mean the underlying structure of many different forms reveals the same basic structure.  For instance, bats’ wings, human hands, and seals’ flippers share a basic bone structure.  Each of the organisms uses the form for very different purposes: flying, grabbing, and swimming.  But the similarity of the underlying bone structure makes sense if all the forms evolved from a common ancestor.  As each species developed and specialized over the millennia, the basic bone structure developed in markedly different ways to help the species take advantage of evolutionary niches.  Bats developed the ability to fly, humans to grab, and seals to swim.  But such underlying similarity is utterly confusing if we assume that each species was created as is.  Why would a designer use the same underlying bone structure for each instead of coming up with more efficient ones for each ultimate use?
    That is, if the bat was made to fly, why wouldn’t its bone structure be markedly different from the bone structure of a seal flipper?  Just as with the embryonic evidence, the only way it makes sense is if the designer deliberately set out to obscure its
    (His?  Her?) role in the design.  It only makes sense, in other words, if God not only designed the vast variety of life, but then made it look as if that variety had evolved from common ancestors.
    Which explanation makes more sense?
  • There are other specific examples that flesh out the argument.  One that Darwin used was that of the ichneumon wasp.  This is a
    type of wasp that lays its eggs directly into or on the body of a host, something like a caterpillar.  The mother wasp then paralyzes the prey.  When the eggs hatch, the wasp larvae eat the living but powerless body of the host.  They first eat the non-vital organs such as fat cells.  That ensures that the host will stay alive as they feed.  Only after they have eaten the still living flesh do they finally eat the vital organs and kill the unhappy host.  Why, Darwin asked, would a benevolent God create such implacable suffering?  If the panoply of living things were created, why create such cruelty?  It makes no sense.  Of course, Darwin could have taken refuge in the traditional answer to such questions: God’s ways cannot be known to us.  He may have reasons beyond
    our knowing.  But for Darwin and evolutionists that followed him, there was a much more obvious answer.  The reason animal life could be so cruel was because it had not been designed in such detail.  God did not create the vampiric wasp as such.  Rather, the wasp evolved to take advantage of the flesh of its prey.  It evolved in its ability to feed its young in this peculiar and revolting
    way.  In other words, if God created the wasp this way, we are presented with a moral dilemma that we can only overcome
    with a series of difficult mental gymnastics.
    But if life forms evolved to take advantage of evolutionary niches, the process makes entire sense.
  • The idea of evolution is repeatedly confirmed by new evidence.  For instance, the basic idea of species changing by a long slow process of natural selection came from Darwin and Wallace in 1859.  They had no idea about a lot of how it might work.
    But as scientists today find out more and more about the nature of life, each new piece of information confirms the basic notion of evolution.  For instance, scientists have had great success in recent years in decoding the genomes of humans and other species.  They have charted the genes that make up the recipe of the human species.  And they have found that those genes are almost identical to genes from similar species.  They are even very similar to the genes of very different species.
    Sharing so much of the same genetic make up confirms the notion that life on earth descended from a single source.
    Darwin and Wallace had no notion that this evidence would ever exist.  But it fits perfectly with their predictions of how such genes should look.  It confirms their suggestions.  There was no way that Darwin could have understood the evidence from the human genome.  Yet it confirms the idea of evolution in vivid ways.  Even during Darwin’s lifetime, he doubted the feasibility of his evolutionary scheme.  Based on the best scientific understandings of his time, there was no way that the earth could be ancient enough for evolution to have occurred.  Later scientific discoveries established a far more ancient age of life on Earth than Darwin realized.  Thus, even when his own faith was shaken in the feasibility of his notion, he was still proven correct.
  • When evidence piles up this way, the only way around it is to imagine that God created a trail of evidence meant to fool humans.  He created a universe that pointed in a false direction, to test whether humanity could overcome the evidence of reason to cling to faith.  Why would He do that?  Why would He want to fool people?  And, if He wanted to give humans a test about whether they would hold fast to His revealed truth in the face of overwhelming rational evidence, why would He give the majority of humans a non-Christian tradition to cling to?  It would mean that God wanted people to cling to a lifeboat of revealed religion instead of walking on the land that was only a few feet below them, then provided them with a lifeboat that wouldn’t float.  That does not seem consistent with a God of infinite love.