Thursday, January 7, 2010

What is "Evolution"?

One of the most confusing terms bantered around in science/faith discussions is "evolution." In fact, a homeschool mom wrote me just a couple days ago alerting me about a Christian Charlotte Mason curriculum. Upon downloading the sample pages, I noticed that it used the following definition:
Some people today think that the world and everything in it just happened by accident; it wasn’t created by God. That belief is called “evolution.”
My immediate thought was, "Wow, that's really general." Fuz Rana posted a great series of various uses and definitions on the Assist news service today, "Tips for Handling the ‘E-Word’" which offers a more nuanced definition. Here is a short excerpt:
As a biochemist, I think of evolution as fitting into one of five distinct categories.

1. Microevolution refers to changes happening within a species. For example, peppered moths changed wing color in response to rising pollution in Britain caused by the Industrial Revolution, thus allowing them to continue to evade predators via camouflage.

2. Speciation occurs when one species gives rise to a closely related sister species. The finches on the Galapagos Islands provide a textbook example of this kind of transformation. An ancestral South American finch species arrived at the Galapagos Islands and eventually became a variety of species that differ primarily in body size and in beak size and shape.

3. Microbial evolution describes changes in viruses, bacteria, archaea, and single-celled eukaryotes (cells that contain a nucleus). Common examples of such changes are the acquisition of antibiotic resistance in bacteria and the emergence of drug-resistant strains of malaria parasites.

4. Chemical evolution refers to the processes that presumably generated Earth’s initial life-forms. According to this model, chemical selection transformed a complex chemical mixture of simple compounds (known as the prebiotic soup) into protocellular entities that further evolved to yield the first true cells.

5. Macroevolution refers to the change of one kind of animal into an entirely different kind. Examples would include humans’ evolving from a primate ancestor, whales’ evolving from a terrestrial wolf-like mammal, and birds’ evolving from dinosaurs. The question of whether macroevolution has actually occurred resides at the center of the creation/intelligent design/evolution controversy.
This is a document that is definitely worthy of a complete read. I'd also recommend keeping a copy on file for future reference.

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