Question

Give one example of artificial or human influenced selection this is how we see our relation with our domesticated species. and briefly explain why is it so much easier to show the results of this kind of selection as opposed to selection in the wild with no human intervention

Answer 1

Animals:

Cats

Start with a population of short-haired cats that have been tested with humans who are allergic to cats. Breed the cats that cause the least allergic reaction. Test the offspring with allergic humans and select the ones with the least effect. Continue choosing the least allergy-generating cats to reproduce. The traits that provoke allergies are weeded out, but the resulting breed will probably not be entirely hypoallergenic. Animals without fur are said to have fewer of the allergens that irritate and cause symptoms, however they aren't completely hypoallergenic.

Breeders have also used selective breeding to create exotic pets. In this case, the breeder crossbreeds two different species-- such as the serval and the domestic cat to produce the Savannah cat. Like many other hybrids, many offspring are sterile. Most infertility in hybrids is caused by a difference in chromosome count between the species. F1 generation Savannahs are very difficult to produce due to differences in gestation time and picky mate selection in servals. This can lead to obvious problems that result in aborted pregnancies or kittens born prematurely. Many of the Savannah cats are back-crosses of the F1 to a serval, which produces a cat that is a higher percentage serval. The Savannahs are not all infertile, depending on their genetics, but male Savannahs are infertile until the F5 generation, while females are fertile from the F1 generation.

In wild this trait cannot be produced as natural selection will choose those cats which have fur as fur protects them from other microorganisms.

In plants-

Desired genotypes and phenotypes of various plant species can be achieved through the purposeful manipulation of breeding.

This manipulation can include controlled pollination or genetic engineering (or both) followed by artificial selection of progeny.

Many agencies believe that breeding new crops is essential to ensuring food security and developing plants more suitable to given environments.

Classical plant breeding uses deliberate plant interbreeding to produce new crop varieties with desirable properties.

Allows for the introduction of traits and/or genes from one variety or line into a new genetic background.

Progeny would then be crossed with the high yielding parent to ensure that the progeny were most like the high yielding parent (backcrossing).

Plants can also be crossed with themselves to produce inbred varieties.