Friday, December 4, 2009

Evolution According to Niles Eldredge

 
I've read all of the books by Niles Eldredge. He's one of my favorite science authors [Good Science Writers: Niles Eldredge]. However, I've never really understood exactly what he means when he talks about evolution. He's not a molecular biologist or a geneticist but does he understand the basics of these disciplines? Does he think of evolution as a branch of population genetics or something else? Does he know about random genetic drift?

Some of these questions have been answered in an article that he co-authors with his son in the latest issue of Evolution: Education & Outreach. This is a journal dedicated to teaching evolution correctly. The article outlines a universal evolution curriculum for all grades from kindergarten to university [Lessons from EEO: Toward a Universal Evolutionary Curriculum].
Abstract We propose a human-centered evolutionary curriculum based around the three questions: Who am I? Where do I come from? How do I fit in? We base our curriculum on our experiences as an evolutionary biologist/ paleontologist (NE) and as a secondary level special education science teacher (GE)—and not least from our joint experience as co-editors-in-chief of this journal. Our proposed curriculum starts and ends with human biology and evolution, linking these themes with topics as diverse as the “tree of life” (systematics), anthropology, Charles Darwin, cultural evolution, ecology, developmental biology, molecular evolution/genetics, paleontology, and plate tectonics. The curriculum is “universal” as it is designed to be taught at all levels, K–16. The curriculum is flexible: “modules” may be expanded and contracted, reordered, or modified to fit specific grade level needs—and the requirements and interests of local curricula and teachers. We further propose that students utilize workbooks from online or printed sources to investigate the local answers to the general questions (e.g., “Who am I?”), while classroom instruction is focused on the larger scale issues outlined in the modules of our curriculum.
I don't like the idea of teaching evolution from a human-centered perspective. Our students are certainly used to thinking of biology only in terms of themselves, but isn't it our goal as educators to teach them that this is wrong?

It's the age-old question of whether the best way of teaching is to cater to student misconceptions or confront them.

A key part of any evolution curriculum is defining evolution. I prefer a scientific definition that allows us to distinguish evolution from other process that may look like evolution. The minimal definition is derived from population genetics and it allows us to recognize that different frequencies of blood groups in different human populations is evolution [What Is Evolution?].

Eldredge prefers a different definition in his evolutionary curriculum ...
What is “evolution?” Evolution is the testable, scientific idea that all species of life on Earth are descended from a common ancestor living billions of years ago since life first began on Earth. You can think of evolution as the history of life on Earth—or even as the fate of genetic information through time.

Module 3: What Is Evolution? How Do Humans Fit into the History of Life?

I've always taught that evolution is a process and that it's distinctly different from the history of life. It's like the difference between gravity and the history of our solar system. The formation of our solar system was a unique event that relied upon, and can be explained by, gravity and other general processes. Similarly, the history of life on Earth is a unique event. It can be explained by evolution and other processes but it's not the same as "evolution."

As far as I know, there are no evolutionary biology textbooks that define evolution as the history of life. The Eldredges are proposing a curriculum that's out of sync with most pedagogical approaches to evolution. Is this a better way to teach evolution? I don't think so.

Module 3 also covers the mechanisms of evolution. Adaptation and natural selection are mentioned but the authors go on to say that natural selection is not the only evolutionary process. The others are: speciation, punctuated equilibria, and mass extinctions.

I've always suspected that Niles Eldredge discounts random genetic drift as a legitimate process of evolution. This confirms my suspicion.

I'm very concerned about the content of this article and it's publication in a journal that's devoted to evolution education. If this is what the experts on evolution education are touting as the ideal curriculum then there are only two possible conclusions: (1) they aren't experts, or (2) I'm dead wrong about everything that I've been teaching.

I'm almost afraid to open up the comments on this posting for fear that (2) is the correct answer.



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