tailieunhanh - Lecture Biology (7th edition) - Chapter 23: The evolution of populations

In this chapter, you should be able to: Explain why the majority of point mutations are harmless; explain how sexual recombination generates genetic variability; define the terms population, species, gene pool, relative fitness, and neutral variation; list the five conditions of Hardy-Weinberg equilibrium;. | Chapter 23 The Evolution of Populations Overview: The Smallest Unit of Evolution One common misconception about evolution is that individual organisms evolve, in the Darwinian sense, during their lifetimes Natural selection acts on individuals, but populations evolve Genetic variations in populations Contribute to evolution Figure Concept : Population genetics provides a foundation for studying evolution Microevolution Is change in the genetic makeup of a population from generation to generation Figure The Modern Synthesis Population genetics Is the study of how populations change genetically over time Reconciled Darwin’s and Mendel’s ideas The modern synthesis Integrates Mendelian genetics with the Darwinian theory of evolution by natural selection Focuses on populations as units of evolution Gene Pools and Allele Frequencies A population Is a localized group of individuals that are capable of interbreeding and producing fertile offspring MAP AREA ALASKA CANADA Beaufort Sea Porcupine herd range Fairbanks Whitehorse Fortymile herd range NORTHWEST TERRITORIES ALASKA YUKON Figure The gene pool Is the total aggregate of genes in a population at any one time Consists of all gene loci in all individuals of the population The Hardy-Weinberg Theorem The Hardy-Weinberg theorem Describes a population that is not evolving States that the frequencies of alleles and genotypes in a population’s gene pool remain constant from generation to generation provided that only Mendelian segregation and recombination of alleles are at work Mendelian inheritance Preserves genetic variation in a population Figure Generation 1 CRCR genotype CWCW genotype Plants mate All CRCW (all pink flowers) 50% CR gametes 50% CW gametes Come together at random Generation 2 Generation 3 Generation 4 25% CRCR 50% CRCW 25% CWCW 50% CR gametes 50% CW gametes Come together at random 25% CRCR 50% CRCW 25% CWCW Alleles segregate, and subsequent generations also have three types of . | Chapter 23 The Evolution of Populations Overview: The Smallest Unit of Evolution One common misconception about evolution is that individual organisms evolve, in the Darwinian sense, during their lifetimes Natural selection acts on individuals, but populations evolve Genetic variations in populations Contribute to evolution Figure Concept : Population genetics provides a foundation for studying evolution Microevolution Is change in the genetic makeup of a population from generation to generation Figure The Modern Synthesis Population genetics Is the study of how populations change genetically over time Reconciled Darwin’s and Mendel’s ideas The modern synthesis Integrates Mendelian genetics with the Darwinian theory of evolution by natural selection Focuses on populations as units of evolution Gene Pools and Allele Frequencies A population Is a localized group of individuals that are capable of interbreeding and producing fertile offspring MAP AREA ALASKA CANADA Beaufort