Breeding

To define breeding in animal husbandry, horticulture, and agriculture, it is the application of genetic concepts to enhance desirable qualities. Ancient agriculturists improved several plants via selective cultivation. Pollen from the chosen male parent, and no other pollen, should be passed to the chosen female parent, according to modern plant breeding centres.

Animal breeding involves choosing the ideal trait (for example, high milk production, fine wool), selecting the breeding stock, and describing the breeding system (for example, inbreeding, and crossbreeding). This is the breed definition of biology.

Selective Breeding

Selective Breed Definition Biology

Selective breeding is defined as the process, where humans control the breeding of organisms to eliminate or exhibit a specific characteristic. This type of breeding uses artificial selection to direct genetic transfer of the desirable traits. As opposed to natural selection, selective breeding mainly focuses on traits that will benefit humans.

Selective Breeding Overview

The process entails recognising certain attractive characteristics and locating two members of a species that display certain characteristics. Then, a series of breedings or matings is performed between the individuals with the favored features to form offspring, which exhibit the feature and that may be used for the future matings. The desirable phenotypic traits are then passed from parents to offspring through their genes.

While selective breeding may increase the prevalence of desirable traits by increasing the frequency of favourable genes in the gene pool, inbreeding can also increase the prevalence of undesirable traits that can cause hereditary health problems.

The word ‘artificial selection’ was first coined by Charles Darwin, in his own book, “On the Origin of Species” to define how humans had mirrored the process of natural selection via selective breeding. Darwin has recognized that the forces changing population were the same, but instead of the organisms adapting to the environment artificial selection can be driven by the human needs. Oftentimes, this leads to a decrease in fitness of the organisms due to the reason that adaptive traits can be ignored.

Selective Breeding Examples

Dogs

All modern dogs have been selectively bred by humans around thousands of years. Dogs were first bred from the common ancestor of gray wolf (which is Canis Lupus) that was domesticated by the humans with whom it lived in nearby proximity. It is also speculated widely that these animals were first domesticated by the humans for protection and hunting, although all the modern dogs have been bred for multiple reasons, such as performing particular tasks, companionship, for aesthetic purposes, or for entertainment. Now, there are about 400 breeds of dog, which means that they have the widest phenotype range of any mammal.

The highly specific traits, which are selectively bred into dogs can come at a huge disadvantage to their health. Not only could a lack of genetic variation within the gene pool trigger certain inherited health issues, but dogs bred with intentionally accentuated physical features which also suffer from their unnatural physical shape. For example, the ‘flat-faced’ breeds and bulldogs can suffer from breathing problems, while some large dogs commonly suffer from bone tumors because of their excess body weight.

Plants and Livestock

Almost all of the food, which is consumed by modern humans has been selectively bred about thousands of years. Around 10,000 years ago, when the humans began living in either semi-permanent or permanent settlements, they started to cultivate crops on their own and herd flocks of livestock firstly.

In plants, selective breeding began unintentionally selecting vegetables and fruits for qualities like sweetness and large size; seeds of plants with the desired qualities would have been given a chance to germinate through human consumption and cultivated within their latrines (or toilets).

Other desirable characteristics such as seedlessness, oil content, and fleshy texture were all altered over time, rendering most human-cultivated vegetables and fruits unrecognisable when compared to their wild equivalents. The similar process took place with domesticated animals such as chickens (considerably larger than their wild ancestors), sheep (bred for thicker wool), and the cattle (bred for increased milk yield or more muscle mass).

Hunting

Not selective breeding is beneficial to humans, always. Outside biology, selective breeding is practiced accidentally. Poachers, who hunt and kill elephants and rhinoceros for valuable ivory and rhino-horn, have in recent years caused an unintentional selection for animals with smaller tusks and horns. As the males having the largest horns are the most desirable to the hunters, the genes which control for size are being removed from the population, rapidly.

In addition, a gene mutation that results in elephants with no tusks at all is increasing within the population. With population numbers greatly reduced because of hunting pressure, it can be possible that elephant tusks could entirely disappear. This is one of the examples of the effect that pressures of modern human populations have on wildlife.