Artificial selection in action: more elephants are being born without tusks

Why Evolution Is True

What do you expect if hunters or poachers selectively kill elephants with big tusks—either for trophies or their ivory? This is actually a form of artificial selection, and it will have the expected results: elephants with smaller tusks will be more likely to survive and reproduce, and if there’s genetic variation for tusk size or presence, which there almost certainly is (there’s genetic variation for nearly every trait, accounting for phenomena like the ability of humans to change the gray wolf into Chihuahuas, greyhounds, sheepdogs, and so on), the “tuskiness” of elephants will change over time. Tusks will get smaller, or even disappear.

You can also predict that if tusks are more important for one sex than the other, that the natural “counterselection” against tusk reduction will be stronger in that sex, so that the reduction in size or presence over time will be slower and, ultimately, might stabilize at…

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