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I finished Jerry Coyne’s Why Evolution Is True last night. He said that hobbits lived 18,000 years ago in Indonesia (page 207), that paleontologists think the T-Rex had feathers (page 237), that sickle-cell anemia helped black Africans to ward off malaria (page 214), that there is a mutant gene that protects a person from the AIDS virus (page 219), and that food lacks an inherent flavor, meaning that “Rotten meat is probably as delicious to a hyena as an ice cream sundae is to us” (page 245). I guess truth can be stranger than fiction! (For an Answers in Genesis take on the hobbits, see here.)
I didn’t really get something that Coyne says about homosexuality. Coyne states on page 228:
Homosexuality? Even though this behavior seems the very opposite of what natural selection would foster (genes for gay behavior, which don’t get passed on, would quickly disappear from populations), one can save the day by assuming that…homosexual males stayed home and helped their mothers produce other offspring. In this circumstance, “gayness” genes could be passed on by homosexuals producing more brothers and sisters, individuals who share these genes. None of these explanations, by the way, are mine. All of them have actually appeared in published scientific literature.
Coyne’s not overly enthusiastic about evolutionary explanations for human behavior, for he treats them as speculative. Personally, I don’t understand the view about the gay gene that he discusses above. Are gays prone to incest? Is that what it’s saying?
I did appreciate, however, the evolutionary explanation for depression that Coyne mentions:
Depression? No problem: it could be a way of withdrawing adaptively from stressful situations, mustering your mental resources so that you can cope with life. Or it could represent a ritualized form of social defeat, enabling you to withdraw from competition, recoup, and come back and struggle another day.
On page 228, Coyne wonders why so many animals sleep. Maybe sleep, too, is a way for them to recoup so they can come back and struggle for another day.
I like the idea of introversion being something positive—a withdrawal that occurs so I can recoup!
On pages 218-219, Coyne addresses the question of “Are we still evolving?” He says that medicine, eyeglasses, sanitation, etc., have have allowed us to compensate for bad genes, so they get passed on, rather than being selected out. One doesn’t have to be particularly fit in order to survive and to pass on his genes. (And, lest one call Coyne a eugenicist, Coyne classifies himself as among the unfit!)
Coyne also says that “genes that were once useful may, due to cultural change, now have destructive effects.” For example, a love for fats and sweets may have given our ancestors “a valuable but rare source of energy”, and they ate fat to “store up calories for lean times”. But the love of fats and sweets today gives us “tooth decay, obesity, and heart problems”. Some of what we inherited from our ancestors harms us, Coyne asserts. But could natural selection weed out the human love for fats and sweets?
I’ve been writing about this book for weeks, and I didn’t do it complete justice, for I wrote about the things that interested me. You can read the book for yourself to learn more about Coyne’s case for evolution.
Next Saturday, I may start Henri Blocher’s In the Beginning, which is about Genesis 1-2. Stay tuned!
