Changing the Living World Chapter 13.1 Changing the Living World

Selective breeding takes animals with the best or desired traits and breeds them to pass those traits to offspring. Many domestic animals, like horses, cats, dogs, and farm animals, and most crop plants have been produced by selective breeding. Selective Breeding

Hybridization is crossing dissimilar individuals to bring together the best of both organisms. Hybrids are usually hardier than either parent. For example: crossing a plant that is disease resistant with a plant that has better food- producing capacity gives a plant with both characteristics. Hybridization

Inbreeding is breeding animals with similar or the same characteristics. For example: inbreeding is used a lot with dogs to keep their line pure. Like purebred yorkies only being bred with other pure bred yorkies. The risks of inbreeding is that genetically similar individuals are used and there is a chance that 2 recessive alleles will be passed on that will make a genetic defect. For example blindness and joint deformities in German shepherds and golden retrievers. Inbreeding

Breeders can increase genetic variation by making mutations, which is the ultimate source of variation. Remember mutations are any change in the DNA that produces a change in the protein produced. Mutation rates can increase by using radiation and chemicals. Most mutations are harmful. Increasing Variation

Producing New Kinds of Bacteria Scientists have subjected different bacteria to chemicals and radiation and been able to produce useful bacterial strains. Producing New Kinds of Bacteria

Producing New Kinds of Plants Scientists have been able to produce drugs that prevent the chromosomes separating during meiosis in plants. This will produce plants that have double or triple the normal amount of chromosomes. In plants this produces larger and stronger plants. Producing New Kinds of Plants