Reblogged:The Essential Stephen Jay Gould

[Practice Good Theory Blog]

"The Richness of Life: The Essential Stephen Jay Gould" is a collection of Gould's essays, mostly about evolution.

This is not a breezy book; even skipping, it took me months. Nevertheless, it is a rewarding book to anyone who is already past the basic misconceptions about evolution and wants to understand it in a little more detail.

If you still have doubts about evolution vs. creationism/"intelligent design", this may not be the book for you. If you think evolution is a process where individual organisms adapt to their changing environments, or if you think things like "since modern society rewards intelligence,  humans will continue evolve into more intelligent beings", you will need a more basic book than this one.

Here are examples of a few misconceptions this book does tackle, and which resonated with my personal level of ignorance:

1. If a feature exists and has lasted for centuries, it must have some evolutionary advantage. (Perhaps a biologist would think this is a laughable misconception, but I've always thought it was plausible.)

2. Features have to develop very incrementally. So, it is not good enough to explain the advantage of some feature. In order to show that it was produced by evolution, one must also explain the evolutionary advantage of hypothetical features that must have existed and grown into the final feature.

3. Slow changes explain the bulk of evolution, and major cataclysms, warmings, coolings, asteroids, and so on only explain a small part of historical changes.

4. Natural variation is entirely random. Of course this could be true depending on the usage of "random". However, take Gould's example of a few islands where one could classify snails on the islands by two distinct patterns: A and B. One might think that the "A" types on the different islands all had a common ancestor, as did all the "B". However, in fact, they do not. The similar distinguishing factor evolved independently in the different populations. In a similar example, three types of Zebra, evolved their striping independently. [And, on an unrelated note, Zebras are white with black stripes, not black with white stripes.]

5. Evolution favors intelligence, and it is somewhat inevitable that humans would finally rise to become the dominant species.

On this last, Gould says that the typical "fish-to-mammals" charts gives us a false picture of evolution as a left-to-right movement. In fact, evolution often proceeds in the opposite direction: toward simpler forms.

He suggests a different visual model: something like a sphere formed from strands emanating from the center. There are organisms at all diameters of the sphere and they are all evolving, not just the ones that are furthest from the center. Also, each evolutionary step can go outward toward more complexity or inward toward simplicity. Even if we assume a equal probability of either, over time the sphere will increase in diameter, with complex organisms emerging, but the center of gravity (measured by number of species) will continue to stay fairly near the core.

[Caveat: Everything above is my paraphrase, and integration, and not to be taken as "essential Gould.'

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