Applied biology : an elementary textbook and laboratory guide / by Maurice A. Bigelow and Anna N. Bigelow.
- Maurice Bigelow
- Date:
- 1911
Licence: In copyright
Credit: Applied biology : an elementary textbook and laboratory guide / by Maurice A. Bigelow and Anna N. Bigelow. Source: Wellcome Collection.
583/616 (page 567)
![the hundreds of varieties of animals and plants which are raised under domestication. For example, we have dozens of varieties of chickens at the poultry shows and most of them are known to have descended from certain breeds; and prob- ably all of them came from one or few wild species, one of which was certainly the East Indian jungle-fowl. Several hundred varieties of pigeons have developed from one (or possibly a few) species of wild pigeon. Numerous varieties of many common plants cultivated for food, ornament, or other use have been selected and improved by horticulturists. In short, any one who looks through books describing the numerous breeds or varieties of common domesticated ani- mals and plants Avill not doubt the fact that organisms do change. And it must be remembered that most of these changes under domestication have occurred within a few hundred years; while tens of thousands of years have been available for changes in wild animals and plants. It should be noted that man has affected animals and plants under his care chiefly by selecting peculiar individuals. When we speak of making a new variety of corn or a new breed of cattle we simply mean that we have selected for propagation certain individuals that by nature were better than their relatives. For example, breeds of hornless cattle have within recent years been started by selecting individuals born without power of growing horns and able to transmit this characteristic to their progeny. Likewise, horticulturists select every year certain extra-valuable plants and from them obtain seed of new varieties. With new varieties of either animals or plants improvements may be made with each new generation by selecting the best individuals as parents. For example, the hornless cattle arc now being im])roved ra]')idly by selecting for propagation only those which are entirely hornless and which are also excellent for milk or meat. This is an illustration of the kind of selection which scientific agriculturists are constantly applying to all kinds of animals](https://iiif.wellcomecollection.org/image/b28065396_0583.jp2/full/800%2C/0/default.jpg)
