UNIT 4 Evolution A BRIEF REVIEW OF SUBTOPICS

UNIT 4 – Evolution A BRIEF REVIEW OF SUBTOPICS

Adaptation & Variation n n Extinction Adaptations: ¡ ¡ ¡ n Structural Behavioural Physiological Variations ¡ ¡ How do variations develop? How do variations become adaptations?

Adaptation & Variation (con’t) n n n Mutations Selective advantage Eg. Antibiotic resistance in staph. bacteria

Darwin & Natural Selection n n General info about Darwin General info about voyage of Beagle, research and observations in Galapagos Eg: Turtles & Finches Origin of Species Controversy surrounding Darwin

Darwin & Natural Selection (con’t) Natural Selection n n Process of change in populations over many generations Individuals with certain traits survive local environmental conditions Pass on favourable alleles to offspring Environment exerts ‘selective pressure’ Assumptions of Natural Selection n n Variation Competition Fitness Adaptation

Darwin & Natural Selection (con’t) Concepts: n Natural Selection n Fitness n Selective pressure n “Descent with Modification” n Artificial selection

Mechanisms of Evolution Factors that Change Allele Frequencies: • Mutation • Gene Flow (Migration) • Non-Random Mating • Genetic Drift • Natural Selection

Mechanisms of Evolution (con’t) n n “The Bottleneck Effect” “The Founder Effect”

Types of Natural Selection RECALL: n n Result of the environment selecting for individuals with certain traits that make them better suited to survive and reproduce Over many generations, frequency of alleles of many different genes may change, resulting in significant changes

Types of Natural Selection (con’t) 1. 2. 3. 4. Stabilizing Selection Directional Selection Disruptive Selection Sexual Selection

Types of Natural Selection (con’t) Long Term Evolution: n Gradualism n Punctuated Equilibrium

Evidence of Evolution Topics Discussed: n Fossil record n Radiometric Dating n Transitional forms n Biogeography

Evidence of Evolution (con’t) Topics Discussed: n Embryonic development n Homologous structures n Vestigial structures n Atavisms n Micro-evolution happening today

Evolution of Humans n n Early primates Brain development (cranial capacities) Transition to 2 bipedal and life out of trees and onto plains Eg: Ardi

THE END … Questions? n “Hey, quit Following me!” n