Breeds and Variaties

  • Created by: BethCM
  • Created on: 25-01-18 17:51

Why are new breeds and varieties created?

Agriculture

Cattle will have better characteristics for producing meat than others. To improve meat yields, a farmer could select cows and bulls with these characteristics and breed them together. After doing this, and selecting the offspring for several generations, the farmer would get cows with very high meat yield.

Medical Research

In studdies investigating reasons for alchoholism, rats have been bred with either a strong preference for alcohol or a weak preference for alchohol. This allows researches to compare differences in the behaviour and the way the brain works with other tested rats.

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Wha are GMO's

Genetically modified organisms or GMO's are being used to help provide food for people who suffer from hunger.

One reason they might want to genetically engineer crops is to make them resistant to pests or to end world hunger and produce masses of the same product.

 

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Selective Breeding

Selective breeding is when humans artificially select the plants or animals that are going to breed so that the genes for particular characteristics remain in the population.

The basic process involved in Selective Breeding:

1)From your existing stock select the one which have the characteristics you're after.

2) Breed them with each other.

3) Select the best of the offspring, and breed them together.

4) Continue this process over several generations, and the desirable trait gets stronger and stronger. Eventuall, all of the offspring will have the characteristic.

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Selective Breeding - Domestic Plants and Animals

1) The main problem with selective breeding is that it reduces the gene pool. This is becasue the best animals or plants are always used for breeding - And they are all closely related. This is called inbreeding

2)Inbreeding can cause health problems becaus ethere is more of a chance of the organisms inheriting harmful genetic defects. e.g. Pugs often have breathing problems. This leads to ethical considerations particularly if animals are deliberately bred to have negative characteristics for medical research.

3)There can be a problem when new diseases come about. Theres not much variation in the population so theres less chance of resistance alleles being present.

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