Chapter 2 Microevolution And Evolutionary Anthropology PDF

Chapter 2 Microevolution and Evolutionary Anthropology 2-1 Copyright © 2010 Pearson Education Canada 2-1  Chapter Goals Understand:  Population genetics  Natural selection  Adaptation...

Chapter 2 Microevolution and Evolutionary Anthropology 2-1 Copyright © 2010 Pearson Education Canada 2-1  Chapter Goals Understand:  Population genetics  Natural selection  Adaptation 2-2 Copyright © 2010 Pearson Education Canada 2-2  Population Genetics: Genetic Drift Random changes in gene pool over time. Three important outcomes: 1.Reduces within-population genetic variation 2.More likely to effect small populations. 3.Increases between- population genetic variation. 2-11 Copyright © 2010 Pearson Education Canada 2-3 Figure 03.21  Population Genetics: Gene Flow Movement of genes between populations. Two important outcomes: 1.Increases within-population genetic variation. 2.Reduces between- population genetic variation. 2-12 Copyright © 2010 Pearson Education Canada 2-5  Natural Selection Any consistent difference in fitness among phenotypically different biological entities. Deterministic process involving differential reproductive success. Acts only on existing variation. 2-13 Copyright © 2010 Pearson Education Canada 2-6  Fitness In evolutionary anthropology, fitness involves selection for heritable traits. Two properties: 1.Involves success of biological entity in producing offspring. 2.Represents average contribution of allele or genotype to succeeding generations. 2-14 Copyright © 2010 Pearson Education Canada 2-7  Three Modes of Selection Directional Selection: process favouring either higher or lower values of character. Increases variation between populations exposed to different environments (i.e., = different selection forces). Stabilizing Selection: Average phenotype is fittest. Reduces variation within populations. Disruptive Selection: both extremes of trait are favoured. 2-15 Copyright © 2010 Pearson Education Canada 2-8 Three Modes of Selection 2-16 Copyright © 2010 Pearson Education Canada 2-9  Natural Selection and Biological Evolution Not necessarily the same thing. Biological evolution can occur without natural selection. 2-17 Copyright © 2010 Pearson Education Canada 2-10  Adaptation Process and feature. Process: Change in organism enabling it to better reproduce and survive in environment. Feature: Characteristic that performs function of utility to organism possessing it. 2-18 Copyright © 2010 Pearson Education Canada 2-11  Behavioural Adaptations Socio-biology: Study of animal behaviour based on assumption that genes control behaviour. May work in insects, but not in humans because we have no or few instinctual behaviours. In evolutionary anthropology, behaviour seen as trait with genetic and phenotypic components that can be influenced by selective pressures. 2-20 Copyright © 2010 Pearson Education Canada 2-12  Two Misconceptions on Natural Selection and Adaptation 1. There is no “perfect design” for any biological entity. Why? Because the environment is always changing. 2. Natural selection and adaptation have no goal. There is no “finish line” for the evolutionary process. 2-21 Copyright © 2010 Pearson Education Canada 2-13 Figure 01.05  Figure 01.11 Equilibrium Change Equilibrium Figure 01.09  Figure 01.11 Equilibrium Change Equilibrium Figure 01.12 Figure 01.10