The basic engine for evolution is gradual changes over time if beneficial to the organism will be selected when these changes give the organism a competitive advantage. These gradual changes are the result of mutations to the DNA which if beneficial makes the organism more fit then others of it species. Being more fit it is able to pass on the beneficial mutations to its progeny. As these changes build up eventually we have a new organism. All this takes time. Fortunately mutations do not happen frequently. I say fortunately because the majority of mutations are either lethal (39.6%) or non-lethal deleterious (31.2%). About 27.1% are neutral which leaves 2.1% of mutations as beneficial. These figures were taken from Motoo Kimura, an influential theoretical population geneticist’s neutral theory of molecular evolution. Find more about this here (http://en.wikipedia.org/wiki/Neutral_theory_of_molecular_evolution) and here (http://en.wikipedia.org/wiki/Mutation#Distribution_of_fitness_effects). I have taken you on a round about way to show that evolution takes time and moves in small incremental steps with each step needing to provide a survival benefit in order to be selected by natural selection.
So where do butterflies come into this post? This past year I got a chance to see Metamorphoses produced by Illustra Media. Metamorphoses shows the life cycle of butterflies and what I had never thought of, what goes on in the pupae/chrysalis during the change from caterpillar to butterfly. I had always thought that something such as happens when a tadpole changes into a frog went on in the chrysalis. I just figured that the caterpillar started to change, developing wings, different shaped legs and moth parts and emerged as a butterfly.
What actually happens is amazing. Once the caterpillar sheds it skin exposing the chrysalis the insides of the caterpillar dissolve into what is a caterpillar soup of DNA, enzymes, proteins amino acids and stem cells. Then over time all these parts slowly become a butterfly. What struck me was how in the world could all this evolve gradually? This is not just a chicken or egg problem where we need to determine which came first butterfly or caterpillar but a how do you gradually get past the liquid step to the butterfly.
Somehow we have to get from either a caterpillar that once produced eggs that gave birth to other caterpillars or a butterfly that once produced eggs that gave birth to other butterflies to a caterpillar that no longer produces egg but dissolves itself in order to transform into a butterfly that produces eggs that give birth to caterpillars rather than butterflies. Talk about an irreducibly complex life cycle. How does this process evolve?
Now I admit when I first heard this I though that can’t be right. But further research from different sources all confirm that during the chrysalis the caterpillar does indeed break down into this biotic soup from which a butterfly is formed. I have yet to find a source to dispute this. I do see the benefit of the caterpillar/butterfly combo. Caterpillars are not equipped to travel and if left to theirs selves would eat all the foliage from their preferred plant. The butterfly cycle helps distribute the eggs to different areas. But how this evolved escapes me.
Let’s start with the egg and lets for arguments sake assume the caterpillar came first. We could do the butterfly first but this just seems logical. So we have caterpillars hatching from eggs munching on leaves and laying eggs to beget other caterpillars. Then we have a mutation, but which mutation? It would seem we have some choices, a mutation that either gives the caterpillar stem cells a switch that will allow them to form a butterfly or different stem cells that form a butterfly or maybe the mutation enabled the caterpillar to form a chrysalis at the end of its life cycle. Maybe the mutation allows the caterpillar to dissolve into component parts. The problem is what evolutionary benefit does either of these give the caterpillar? Natural selection does not select with a future benefit in mind, it is after all the blind watchmaker. No, each mutation needs to have some independent benefit and not just be a benign mutation. What about a number of mutations all at once, couldn’t that do it? The odds are not good. Since over 70% of mutations are either lethal or harmful to the organism and only about 2% actually are beneficial the more mutations that happen at once the greater chance that one or more will harm or kill the organism.
Until proponents of evolution can take us through the necessary steps to get from caterpillar to butterfly macroevolution will have its detractors. However, if the butterfly was the only challenge to gradualism we might give it a pass. But in fact there just is not a clear path for changes from one type to a new type. Evolution can be shown how it works within an organism, for example how bacteria can develop immunity to a particular antibiotic but in those cases you start with a certain type of bacteria and end up with the same type. What changed were not the bacteria but the bacteria population. This is microevolution. Most people regardless of their position on evolution accept microevolution.
What evolution lacks is any step by step explanation for the creation of complex biological system or how one creature changes into some other creature with completely different structure and function. What we get is speculation and conjecture. In fact most of the explanations I have heard hark back to Lamarck and his Inheritance of acquired characteristics theory. The classic example of this is the giraffe that kept reaching its neck to get higher and higher leaves and passed this down to its descendants. One example I was recently given is the theropod dinosaurs with feathered arms used their arms for balance and slowly these arms developed into wings. What is lacking is any way the arms turned into wings and what survival benefit was gained during the change.
So why don’t we see biologist doing research to show how these changes take place? After all that would help quiet people like me. The problem as I see it is that evolution is presented as settled science. Since it is settled why do a costly research project to prove something that is already settled? The problem is there is no such thing as settled science. Science should always be looking for more answers and never be satisfied that all questions have been answered. Science is not done by majority vote. At one time when the steady state theory of cosmology reigned everyone knew that the universe was eternal. Then in 1964 two American radio astronomers, Arno Penzias and Robert Wilson, discovered cosmic background radiation and realized it was the same in all directions. What came from those and other observations was the Big Bang theory of the universe. In fact the name Big Bang theory was originally derisive because it went against what all the experts thought. I would be extremely interested if someone can point me to a source showing how the butterfly evolved.
Next time, I will look at natural selection and its ramifications. Then I hope to look at the problems identified by Darwin in his work On origin of Species. After that I hope to look at the first life problem, humans, apes and missing links, stretching the truth – frauds and hoaxes and the problem of complexity. Finishing up with free will, evil and the meaning of life as it pertains to evolution and my conclusions.
Once again thanks for taking the time to read my blog and for those making comments a special thanks. Your comments, especially when it come from the other side of the argument help me to clarify my own thoughts and keep me thinking. Finally, sorry for such a long delay in postings but I took time off during the holidays to enjoy time with friends and family.
Have a blessed day,