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Selective Breeding. Why do humans want to alter organisms?. They want desirable traits from these organisms, for example: Bright, colorful flowers Pesticide resistant vegetable and fruit crops that can live longer Strong, powerful farm animals, race horses, or perfect-looking show dogs.
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Why do humans want to alter organisms? • They want desirable traits from these organisms, for example: • Bright, colorful flowers • Pesticide resistant vegetable and fruit crops that can live longer • Strong, powerful farm animals, race horses, or perfect-looking show dogs
How can humans accomplish this? • There are three methods of developing organisms with desirable traits: • Selective breeding • Cloning • Genetic Engineering
Selective Breeding • The process of selecting a few organisms with desirable traits to serve as parents of the next generation. • There are two types (inbreeding and hybridization) • Increases the value of plants and animals to people • Dairy cows produce more milk • Larger, juicer strawberries • Faster, stronger race horses
Inbreeding • This 1st selective breeding process crosses two individuals that have identical or similar sets of alleles. • Goal is to produce breeds of animals with specific traits • Mating strong purebred German Sheppard police dogs with the same traits to produce puppies that are very similar genetically.
Hybridization • This 2nd selective breeding process crosses two individuals that have genetically different sets of alleles. • Goal is to produce breeds of animals with a combination of specific traits • Taking a fast horse and matting it with a tall horse in hopes that the baby horse will be tall and fast.
What are clones? Genetically Identical copies
Cloning mammals • Sexual reproduction produces variation not clones. Why?
Dolly The Sheep Hello DollyDolly was the first mammal cloned from an adult cell. She was born in 1996 and died in 2003. She was 6 when she died, about half the usual age for a sheep
Genetic Engineering • Transferring a gene (or more) from the DNA from one organism to the DNA of another organism. • Why? Produces medicines, improve crops, and may cure genetic disorders.