Lecture 05 Outline Chapter 24

Lecture 05 Outline Chapter 24 - Lecture 5: MACROEVOLUTION...

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Lecture 5: MACROEVOLUTION Slide 1 (a repeat from earlier) Natural selection: generates phenotypic adaptation Adaptations are traits or suites of traits that are favored by natural selection. Morphological adaptation e.g. cryptic skin color Behavioral Adaptation e.g. mutual grooming - Physiological Adaptations e.g. enzyme synthesis in a biochemical pathway Slide 2 Summary: Microevolution: Changes over time in allele frequencies in a population evolutionary change below the level of speciation. Microevolution processes that change gene frequencies include: Migration Non-random mating Genetic Drift including bottleneck effect Mutation THE SOURCE OF NOVEL VARIATION Natural Selection THE SOURCE OF ADAPTATION Slide 3 Macroevolution: Broad patterns of evolution over long time spans: the origin of new taxonomic groups (new species, new genera, new families, new kingdoms) Evolutionary theory explains macroevolution Slide 4 What is a species? Species from latin “kind or type” Forms with distinct: Morphology, Physiology, Behavior, DNA sequences, usually species exhibit distinct differences in some or all of these parameters Slide 5 The Biological Species Concept (the most commonly used species concept)
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“a group of interbreeding natural populations that are repr oductively isolated from other such groups” Slide 6 What makes us a species?: 1. all populations have the capacity to interbreed Humans: Several genetic groups (races) interbreed freely Slide 7 Humans are undergoing genetic coalescence due to extensive gene flow between races Races become decreasingly distinct Slide 8 What makes us a species?: 1. all populations have the capacity to interbreed. 2. We do not interbreed with other species. e.g. Amphibians and Humans: Very distantly related, different genome, karyotype, anatomy, ecology etc. Slide 9 e.g. arrow poison frogs. closely related. live together. but do not interbreed. Each is a biological species. Slide 10 Where do new species come from? New breeding population Evolution Reproductive isolate New Species Biodiversity Slide 11 New breeding population reduced gene flow Slide 12-13 Micro evolution ; Bottleneck Genetic Drift (small population) Mutation Natural selection & consequent Adaptation Slide 14-15 Reproductive Isolation (followi ng microevolution) when populations in this case come together by ‘secondary contact’ Slide 16
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Reproductive Isolation: barriers to gene flow Prezygotic barriers impede mating or fertilization Postzygotic barriers prevents successful propagation of
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This note was uploaded on 11/08/2011 for the course BSC 2011C taught by Professor Klowden/crampton during the Fall '11 term at University of Central Florida.

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Lecture 05 Outline Chapter 24 - Lecture 5: MACROEVOLUTION...

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