Chapter 20: Selective Breeding Flashcards
Selective breeding is…
and why is it beneficial?
…the traditional method for improving crops and livestock,
- higher yields
- disease resistant
- hardier (survive in harsher climates)
- have a better balance of nutrients in the crop (e.g. more types of amino acids needed by humans)
Genetic engineering is…
…a faster way, which transplants genes for a desired characteristic into an organism.
However, genetic engineering offers many potential benefits but carries the risk of unexpected harmful effects.
Four steps of selective breeding…
- Decide which characteristics are important
- Choose parents that show these characteristics
- Select the best offspring from parents to breed the next generation
- Repeat the process continuously
Examples of selective breeding…
Wheat: Producing disease-resistant wheat by crossbreeding wheat plants with disease resistance and wheat plants with a high yield.
Dairy cattle: Increasing milk yield by selecting bulls from high yield herds and breeding them with cows that have the best milk production.
Cattle breeds: Selective breeding can also be used to modify other characteristics of cattle.
Problems with selective breeding…
- Future generations of selectively bred organisms will all share very similar genes. This could make some diseases more dangerous as all the organisms would be affected.
- Some genes would be lost, making it more difficult to produce new varieties in the future: ‘inbreeding can lead to a reduction in the size of the gene pool’.
Examples of genetic engineering…
How genetic engineering is done…
Can you answer these questions???
