Selective Breeding or Artificial Selection

Selective Breeding The process of breeding plants and animals for particular traits. This is synonymous with Artificial Selection. This selection process is "artificial" when human preferences for specific traits have an effect on the changes in a population or species.

Domestication and Selective Breeding Domestication: Accentuating plant and animal traits at the genetic level as desired by humans. – Why is domestication different than taming? Answer: It differs from taming in that a change in the genetics and physical traits of the animal occurs. Taming is the process by which animals become used to the presence of humans. – How does this picture portray both domestication and taming?

Advantages of Selective Breeding Selective breeding establishes and maintains certain stable traits that animals will pass to the next generation. Traits that humans find desirable in domesticated species such as: – disease resistance, strength, calmness, more lean meat, endurance, etc. In many cases, this makes the species stronger.

Disadvantages of Selective Breeding Breeding from too small of a gene pool can lead to the following: – Passing on of undesirable characteristics – Collapse of a breed population due to what is called inbreeding depression Breeding for only one trait, over all others, can cause problems. – For example, certain roosters bred for fast growth or heavy muscles did not know how to perform the typical rooster courtship dance. The dance bonds the roosters to the hens. No mating dance led the roosters to kill the hens after reproducing with them. This is not a trait which encourages survival of the species!

Examples of Selective Breeding Carrots in a variety of colors

Variegated ears of maize (Indian corn) Examples of Selective Breeding

Examples of Selective Breeding Charolais cattle produce beef that has more red meat and less fat.

Examples of Selective Breeding Chihuahuas and Great Danes are bred for size.

Selective Breeding and Natural Selection The main difference between natural selection and selective breeding is human involvement. In natural selection, the reproduction of organisms with certain traits is attributed to improved survival or reproductive ability (survival of the fittest). In selective breeding, humans favor specific traits and control breeding for those traits. It is goal oriented.

Historical Connection to the Contribution of Scientists Scientists, such as Charles Darwin, have proposed that natural selection and selective breeding both serve as evidence of genetic variation in species and populations over time. Examples cited are the Galapagos finches and domestic animals. – Examples of selective breeding: pigeons, dogs, horses, and cattle