Artificial Selection

Artificial Selection

Humans have deliberately selected which plants and animals shall live and which shall die for thousands of years. We are surrounded from babyhood by familiar farm and domestic animals, fruits and trees and vegetables. Where do they come from? Were they once free-living in the wild and then induced to adopt a less strenuous life on the farm? Non, the truth is quite different. They are, most of them, made by us.

Ten thousand years ago, there were no dairy cows of ferret hounds or large ears of corn. When we domesticated the ancestors of these plants and animals – sometimes creatures who looed quite different – we controlled their breeding. We made sure that certain varieties, having properties we consider desirable, preferentially reproduced. When we wanted a dog to help us care for sheep, we selected breeds that were intelligent, obedient and had some pre-existing talent to herd, which is useful for animals who hunt in packs.

Artificial Selection. Photo by Elena

The enormous distended udders of dairy cattle are the result of a human interest in milk and cheese. Our corn or maize, has been bred for ten thousand generations to be more tasty and nutritious than its scrawny ancestors; indeed, it is so changed that it cannot even reproduce without human intervention.

The essence of artificial selection – for a Heike crab, a dog, a cow or an ear of corn – is this: Many physical and behavioral traits of plants and animals are inherited. They breed true. Humans, for whatever reason, encourage the reproduction of some varieties and discourage the reproduction of others. The variety selected for preferentially reproduces; it eventually becomes abundant; the variety selected against becomes rare and perhaps extinct.

But if humans can make new varieties of plants and animals, must not nature do so also? This related process is called natural selection. That life has changed fundamentally over the aeons is entirely clear from the alterations we have made in the beasts and vegetable during the short tenure of humans on Earth, and from the fossil evidence. The fossil record speaks to us unambiguously of creatures that once were present in enormous numbers and that have now vanished utterly. Far more species have become extinct in the history of the Earth than exist today; they are the terminated experiments of evolution.

May be, a few gastronomic compromises have to be made, but the dinner must be of surprising elegance. Image: © Elena