Monday, November 12, 2007

Repeated Evolution?

One of the more curious features of the fossil record is the pervasive occurrence of convergence. Have you ever heard of this idea? I hadn't until I worked with some scientists.

Convergence is the observation that certain functions or physical structures occur multiple times in different species. Evolutionists might say it this way: "Under natural selection, organisms descending from different ancestors can evolve similar structures and similar adaptations to suit a common purpose." A common example of convergence is the human hand, the dolphin flipper, and the bat wing which all have similar bone structures composed of five digits. If you have a mainstream middle school or high school biology textbook in your home, flip to the chapter on evolution. There is probably a picture of this concept there.

There are many examples of convergence which have been cataloged over the last few years by scientists. The only reason I am citing this one is because it was just announced last week and I think it's sort of interesting.

Ancient Mammal Had Modern Teeth

The fossils of an ancient creature resembling a small opossum and equipped with modern-looking teeth suggest our furry ancestors were far more diverse in the age of dinosaurs than previously thought.

"The story of the earliest mammals is a story of their teeth," said study team member Zhe-Xi Luo, a paleontologist at the Carnegie Museum of Natural History in Pittsburgh. "By tracing their evolution in the rich fossil record of the Mesozoic, we can understand how these cutting and grinding teeth evolved over and over again."...

Paleontologists previously thought tribosphenic teeth evolved once before spreading to all mammals. But a 2001 study by Luo and colleagues suggested tribosphenic molars in monotremes, whose living descendants include the platypus, evolved separately from those of marsupial and placental mammals.

The new fossil lends further support to the idea that similar dental structures for cutting and grinding evolved several times in mammalian evolution.

Convergence is a fact. The question is, how did convergence happen?

Other questions we might ask include, How does evolution account for convergence? Is convergence an evidence for evolution bringing out the same results over and over again? Or does it fit better with the idea of a Creator re-using designs that work well in a given situation?

According to (now deceased) prominent evolutionary biologist, Stephen Jay Gould, if we were to rewind the tape of the history of life backward, we should not observe the same outcomes. After all, evolution is driven by random chance process (although I am aware evolutionists tend to have an aversion to the word "random"). But my question is, How can non-personal, mechanistic processes repeatedly produce the same results? I realize naturalistic evolutionists are going to respond with some version of, "...because that's what works." But it just doesn't seem credible to me to say that mechanistic, non-personal processes will know in advance "what works" and when to stop evolving to something else, much less keep evolving the same body structures over and over again.

Anyways, if you want to reflect more on convergence from a Christian perspective, you can check out a couple of Fuz Rana's articles on the Reasons To Believe web site:

"Convergence: Evidence for a Single Creator"

"Repeatable Evolution or Repeated Creation?"

Dr. Rana has also documented many examples of convergence or "repeated evolution" over the years in the Creation Update archives.

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