1323383925_CHAPTER_7_SPR

1323383925_CHAPTER_7_SPR - EVOLUTION/LECTURE1 Evolution...

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EVOLUTION/LECTURE1 file:///E|/CH7-DRIFT-SPRING-2008/CHAPTER%207%20SPR_2008.html[12/8/2011 2:53:07 PM] Evolution ( PCB 4674 ). Chapter 7. Mendelian genetics in populations II: Migration, genetic drift and nonrandom mating Main topics of lecture: I: Introduction: 1.- The greater Prairie Chicken: A species in danger of extinction II: The Hardy-Weinberg principle and migration: 2.- Migration as an evolutionary force 3.- Empirical research on migration as a mechanism of evolution III: Genetic drift: 4.- A model of genetic drift 5.- Genetic drift and population size 6.- The founder effect 7.- Random fixation of alleles and loss of heterozygosity 8.- An experimental study on random fixation of alleles and loss of heterozygosity 9.- Random fixation and loss of heterozygosity in natural populations 10.- The rate of evolution by genetic drift IV: Nonrandom mating: 11.- The Hardy-Weinberg principle and nonrandom mating 12.- General analysis of inbreeding 13.- Inbreeding depression V: Conservation genetics of the Illinois Greater Prairie Chicken
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EVOLUTION/LECTURE1 file:///E|/CH7-DRIFT-SPRING-2008/CHAPTER%207%20SPR_2008.html[12/8/2011 2:53:07 PM] I: Introduction 1.- The Greater Prairie Chicken: A species in danger of extinction 1.1.- Tympanuchus cupido pinnatus (The Greater Prairie Chicken), is a two-pound bird restricted to the prairies of Central USA. 1.2.- Two hundred years ago, the state of Illinois was covered with prairie and was home to millions of greater prairie chickens. In 1837 the steel plow was introduced in the prairies and this allowed the conversion of prairie into farmland. As the Illinois prairie shrank, the range of the Illinois Greater Prairie Chicken contracted with it (Fig. 6.2) Figure 6.2.: Habitat destruction and the shrinking range of Illinois Greater Prairie Chickens 1.3.- The bird's range contracted, its numbers crashed to 25,000 in 1933; 2000 in 1962; 500 in 1972; 76 in 1990. Efforts to save the Illinois Greater Prairie Chicken began with a ban on hunting in 1933, the establishment of bird sanctuaries in the 60s. Figure 6.3. tracks the number of males displaying in one of the two remaining populations of this species. From the mid-1960s through the early 1970s, the number of birds increased steadily. However, in the mid-1970s the population began to crash again. The population hit its all-time low of six males in 1994, despite the fact that there was now more managed grassland available to the birds than in 1963 (Fig. 6.3.)
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EVOLUTION/LECTURE1 file:///E|/CH7-DRIFT-SPRING-2008/CHAPTER%207%20SPR_2008.html[12/8/2011 2:53:07 PM] Figure 6.3.: Number of male prairie chickens displaying each year on booming grounds. 1.4.- Why did the population continue to decline, even though the amount of habitat available was increasing? And what did wildlife managers do to finally reverse the decline. The answer to these questions involve three phenomena: i.- Migration ii.- Genetic Drift iii.- Nonrandom mating In this lecture we will explore what happens when we relax the assumptions of
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1323383925_CHAPTER_7_SPR - EVOLUTION/LECTURE1 Evolution...

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