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Give one detailed example of evolution occurring in an individual. Agenda: 1. Turn in Cladogram Lab Questions 2. Natural Selection Notes 3. Natural Selection Activity Homework: Genetic Variation Reading and Questions November 17- sycophant- ('si ke fent) - (noun) - a person who praises powerful people in order to get their approval When her career was riding high, the self- deluded actress often mistook sycophants for true friends.
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Trick Question- Evolution Does NOT occur in an individual So now …. Give an example of evolution occurring in a population. How do you know evolution occurred? Why can’t evolution occur in an individual?
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Natural Selection What do we mean by survival of the fittest?
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Fitness Definition of fitness in evolutionary terms means ABILITY TO SURVIVE and PRODUCE OFFSPRING This includes survival, finding a mate, and successful reproduction
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What is Natural Selection? It arises from Darwin’s 4 Postulates: 1.There is variety in a population 2.That variation is inherited 3.More individuals are born than can survive 4.The more advantageous traits (that allow survival and reproduction) will become more prevalent (common) over time Natural Selection
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Consequences of Natural Selection Harmful genes that kill a species before reproduction will get filtered out More beneficial genes will become more prevalent (common) in a population
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Example: Beetles
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Predict what will happen to the population of beetles if….. 1. Trees evolve to have a green color bark 2. Birds evolve to only see green beetles 3. Brown beetles are more prone to disease than green beetles
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Antibiotic Resistance Why is it so important to take the full dose of an antibiotic? What happens if you stop taking your antibiotic when you feel better? Natural Selection works on bacteria and viruses too!
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Antibiotic-sensitive Antibiotic-resistant Initial TreatmentRe-treatment
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Does Natural Selection act on the Individual? Natural Selection acts RANDOMLY on gene mutations that occur RANDOMLY in a population No one can decide to undergo natural selection – its natural! Therefore, natural selection occurs in populations NOT in the individual
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Exit Ticket 1. Using your knowledge of natural selection and genetic mutations, explain how polar bears have white fur 2. Using your knowledge of natural selection and genetic mutations, explain how deer have antlers
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