Ten Questions About Evolution

evolutionI’m going to answer Ten questions to ask your biology teacher about evolution posted on the creationist web site http://www.iconsofevolution.com/:

ORIGIN OF LIFE. Why do textbooks claim that the 1953 Miller-Urey experiment shows how life’s building blocks may have formed on the early Earth — when conditions on the early Earth were probably nothing like those used in the experiment, and the origin of life remains a mystery?

Probably because they were written a long time ago when that experiment was new and topical. Check out Wikipedia for an up-to-date summary of the latest theories of Abiogenesis. Unlike creationists, scientists don’t always claim to know the answers. Instead, they form hypotheses and test them with experiments. The origin of life does indeed remain a mystery at the moment.

DARWIN’S TREE OF LIFE. Why don’t textbooks discuss the “Cambrian explosion,” in which all major animal groups appear together in the fossil record fully formed instead of branching from a common ancestor — thus contradicting the evolutionary tree of life?

The Cambrian Explosion took place over a period of about 20 million years. The major animal groups referred to are all forms of primitive sea life. You must have very old textbooks if they don’t cover this. The Cambrian explosion has been well documented since at least the early 1970’s.

HOMOLOGY. Why do textbooks define homology as similarity due to common ancestry, then claim that it is evidence for common ancestry — a circular argument masquerading as scientific evidence?

A good example of homology is the wing of a bat. If you look at the bones in a bat’s wing, they are almost exactly like the bones in the paws of other mammals. If bat’s were created, why would that be? Homology is compelling. Why do humans have tails (the coccyx)? Why do whales have fingers and toes?

VERTEBRATE EMBRYOS. Why do textbooks use drawings of similarities in vertebrate embryos as evidence for their common ancestry — even though biologists have known for over a century that vertebrate embryos are not most similar in their early stages, and the drawings are faked?

Again, textbooks get out of date. Yes, early embryologists exaggerated the similarities between the embryos of different species. Scientists are human, and not above sensationalism. And yet, there are striking similarities.

ARCHAEOPTERYX. Why do textbooks portray this fossil as the missing link between dinosaurs and modern birds — even though modern birds are probably not descended from it, and its supposed ancestors do not appear until millions of years after it?

Evolution does not claim to progress in an orderly fashion. Archaeopteryx is an intermediate stage between dinosaurs and birds. The fact that it may not be the exact species that modern birds evolved from doesn’t alter the fact that it shows how that evolution occurred. Many more steps along the way have since been discovered, including the fact that many therapod dinosaurs were feathered.

PEPPERED MOTHS. Why do textbooks use pictures of peppered moths camouflaged on tree trunks as evidence for natural selection — when biologists have known since the 1980s that the moths don’t normally rest on tree trunks, and all the pictures have been staged?

The change in colour of pepper moths is well documented. Do you have a better explanation than discoloration of the moth’s environment by soot? From the wikipedia article:

The dark-coloured or melanic moths (carbonaria variety) were not known prior to 1811. After field collection in 1848 from Manchester, an industrial city in England, the frequency of the variety was found to have increased drastically. By the end of the 19th century it almost completely outnumbered the original light-coloured type (typica variety), with a record of 98% in 1895.

DARWIN’S FINCHES. Why do textbooks claim that beak changes in Galapagos finches during a severe drought can explain the origin of species by natural selection — even though the changes were reversed after the drought ended, and no net evolution occurred?

A drought has nothing to do with the reason the finches are interesting. The Galapagos are isolated, making it very difficult for small birds to reach them. Everywhere else in the world, finches aren’t very diverse. But on the Galapagos, where there are few other varieties of bird, there are many different kinds of finch, several of which are specialized to feed on things that finches don’t, otherwise. How do you explain this?

MUTANT FRUIT FLIES. Why do textbooks use fruit flies with an extra pair of wings as evidence that DNA mutations can supply raw materials for evolution — even though the extra wings have no muscles and these disabled mutants cannot survive outside the laboratory?

Drosophila is used as an example because it has a fairly simple genome that was one of the first to be understood, and many generations can be observed in a short period of time. Many mutations can survive outside the laboratory and can give advantages in some circumstances. For example, sickle cell anemia, common in African Americans, is generally harmful, but confers an advantage when infected by malaria.

HUMAN ORIGINS. Why are artists’ drawings of ape-like humans used to justify materialistic claims that we are just animals and our existence is a mere accident — when fossil experts cannot even agree on who our supposed ancestors were or what they looked like?

Again, like Archaeopteryx, though we can’t be sure that Homo Habilis was our direct ancestor, that doesn’t matter. It still shows that a step between apes and humans existed. There is good genetic evidence that humans interbred with neanderthals, though again, they are probably not our direct ancestors.

EVOLUTION A FACT? Why are we told that Darwin’s theory of evolution is a scientific fact — even though many of its claims are based on misrepresentations of the facts?

In science, when a hypothesis stands the test of time, fitting more and more facts, not being contradicted by experiments designed to test it, it becomes a theory. Eventually we take it as fact. Yes, some of the details may be wrong. For example, Einstein showed that, at extremely high speeds, things don’t behave in the way predicted by Newton. Unlike creationists, scientists, once an error is determined, will adapt or completely discard a theory if it doesn’t fit the facts.


About jimbelton

I'm a software developer, and a writer of both fiction and non-fiction, and I blog about movies, books, and philosophy. My interest in religious philosophy and the search for the truth inspires much of my writing.
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