The Greatest Show on Earth, Chapter 10

Chapter-by-chapter thoughts on Richard Dawkins’ The Greatest Show on Earth: The Evidence for Evolution

by John C. Snider © 2009

Chapter 10: The tree of cousinship

Homology.  The fact that, say, mammals all share the same basic body plan, and that each species is more or less a variation on a theme, could either be evidence of shared ancestry, or evidence or a shared Creator.  Dawkins points out that bats and humans (for example) share the same skeletal structure, nearly bone for bone; the differences in the relative proportions.

Shared ancestry, no matter how difficult it may be to conceive the infinity of incremental happenstances needed to arrive at the current diversity of the biosphere, is a far more “parsimonious” theory than a Creator (for then we’d have to explain why the Creator was so wasteful, roundabout, clueless and arbitrary in his designs).  Why make fish swim using side-t0-side motions of the tale, but make dolphins go up-and-down?  Why give whales vestigial limb structures, when a clean design would dictate leaving them out altogether?  And while we’re at it: if the Creator wanted to make it crystal clear that humans are a special creation, why not make us using something entirely different from DNA?

I admit I didn’t grasp this chapter as firmly as I should have, partly because I’m not read-up on biology in general, and partly because I was reading this chapter in the waiting room of an auto repair show, and the man and woman sitting across from me would not shut up.   Nonetheless, it’s clear that scientists can comfortably conclude, by triangulating from a number of sources, that humans share a common ancestry with all living things on this planet.

On to Chapter 11…!

The Greatest Show on Earth is available at Amazon.com and Amazon.co.uk.

Read my thoughts on Chapter 9.

Read my thoughts on Chapter 8.

Read my thoughts on Chapter 7.

Read my thoughts on Chapter 6.

Read my thoughts on Chapter 5.

Read my thoughts on Chapter 4.

Read my thoughts on Chapter 3.

Read my thoughts on Chapter 2.

Read my thoughts on Chapter 1.