BESC 201 1st Edition Lecture 6 Outline of Last Lecture I Biogeochemical Cycles Outline of Current Lecture II Central Case Study of Chapter 3 III Evolution Current Lecture Chapter 3 Lecture 6 Evolution Biodiversity and Population Ecology Central Case Study Striking Gold in a Costa Rican Cloud Forest A new species of toad was discovered only to be extinct soon because of habitat destruction and disease Evolution as the Wellspring of Earth s Biodiversity Evolution change over time genetic changes over generations Natural Selection inherited characteristics enhance survival and reproduction and passed frequency to future generations Natural selection shapes organisms and diversity Key observations 1 Organisms face a constant struggle to survive and reproduce 2 Organisms produce more offspring than can survive 3 Individuals of a species vary in characteristics These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute One generation to the next will lead to better and better traits Selection acts on genetic variation Mutations accidental changes in DNA leading to genetic variation Variation also occurs through sexual reproduction Environmental conditions determine what pressures natural selection will exert global warming is happening too quickly for most species to adapt Evidence of selection is all around us In the example of domesticated animals we breed dogs and cats to get desirable traits only choose to breed like with like artificial selection
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