ISB 202 10-9-08 - ISB 202 10-9-08 Natural selection has...

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ISB 202 10-9-08 “Natural” selection has occurred for millions of years and still happens Over the last 10,000 years, people have used “artificial selection to choose plants and animals for specific purposes Inbreeding (mating between close relatives) increases incidence of diseases and other traits that are linked to recessive genes **inbreeding makes organisms and individuals … How is inbreeding reduced in nature? o In animals? Genes are mixed widely among individuals. o **even biological monogamy is the exception in nature (and “true” monogamy basically doesn’t exist.) o In plants? Many plants are self fertile o Typical flower parts: Anthers are usually above (superior) the stigma. Pollen from anther lands on stigma. Stigma has a sticky substance when ready for fertilization. Pollen grain germinates Pollen tube grows down the style Pollen tube delivers male chromosomes to the ovule (egg). Sometimes anthers are below (inferior) the stigma. With plants, inbreeding leads to reduced yields. o
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ISB 202 10-9-08 - ISB 202 10-9-08 Natural selection has...

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