The Origin Of Species (1859) is Charles Darwin’s magnum opus. These blinks outline a theory of how traits are selected by nature, where the tremendous diversity of life on earth came from and how animals and plants came to be distributed across the planet.
Different domestic animal species divide into breeds that are simply variations on a single species. But did you know that they all descend from a single common ancestor?
Just take the various breeds of domestic pigeon, like the English Carrier pigeon, which is identifiable by its abnormally long neck, or the Brunner Pouter, with its massively protruding breast. Both of these breeds – and all other breeds of pigeon – descend from the wild rock pigeon.
Humankind has played a key role in this process of differentiation as we’ve been breeding domestic animals since the late Pleistocene. Over the millennia, we’ve gotten pretty darn good at it too. For instance, the pigeon breeder, Sir John Sebright, who died in 1846, boasted that he could create a pigeon with any coloration or patterning in just three years. This process is accomplished through what’s called selection.
Here’s how it works:
Breeds are distinguishable by features known as variations. For example, pugs are dogs characterized by a short, wrinkly muzzle.
To create such a breed, a breeder would begin with a group of mongrel dogs. From this bunch, he would select the dogs with the shortest muzzles and mate them. Since the offspring of all animals inherit traits from their parents, this litter of pups would have muzzles that are, on average, shorter than those of the original stock.
From this first litter, the breeder would choose the dogs with the shortest muzzles and breed them again, and so on and so forth for the next several generations. Over time, the offspring would have ever shorter muzzles, until they eventually became pugs.
However, while it’s possible to control this process, most selection is unconscious. In fact, the most shocking results of breeding tend to occur unintentionally.
Just imagine a pigeon breeder who selects and breeds birds with large tails. Unbeknownst to him, while the pigeons’ tails are growing, the bone structure of their tails is also transforming. Because of this, hundreds of years of breeding produced the Fantail pigeon, with a tail structured like that of a peacock.