Biology 102Lecture 9Outline of Last Lecture:I. Dr. Brewton LectureOutline of Current Lecture:I. Clicker QuestionsII. Sympatric speciation and PolyploidyIII. Adaptive radiationClicker Question- Sympatric speciation commonly occurs through ______ in plants, but is more likely to occur through ______ in animals.- Polyploidy….. habitat differentiation and sexual selectiono Polyploidy: when you have more than 2 sets of chromosomes- Biologists have found more than 500 species of fruit flies on the various Hawaiian Islands, all apparently descended from a single ancestor species. This example illustrates- Adaptive radiationo When a bunch of new species form from one common ancestor and they spread out really rapidly (common on island chain)- Why might speciation occur at an unusually rapid pace?- A dominant group of organisms goes extinct, paving the way for the evolution of a new species - The environment changes rapidly, selecting for new traits - This factor would NOT contribute to allopatric speciation.- Gene flow between the two populations continues to occurSympatric Speciation and Polyploidy- Sympatric speciation: when species with a common ancestor arise in the same geographical area.Most plant species have evolved by polyploidy- Polyploidy when there are extra chromosomes and it causes an error in meiosis- Very common in plants- Clothe and feedAdaptive Radiation- Adaptive radiation- when a new species evolves - This occurs because there’s not a lot of other species so there are more resourcesBiology 102- Founder effect- when a population moves to another environment to establish it, this causes genetic
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