ANTH 1102 1st Edition Lecture 10 Outline of Last Lecture I Race in the US II Biological Anthropology A What it Studies B Theory of Evolution C Scientific Theory D Evolution Terms Outline of Current Lecture I Evolution A Theories B Darwinian Evolution II Genetics and Evolution III Biochemical Genetics IV Population Genetics A Four Forces of Microevolution Current Lecture EVOLUTION early ideas to explain fossil record 1800s catastrophism Georges Cuvier fossil record evidences divine natural disasters transformism Erasmus Darwin descent with modification one common ancestor of all living forms uniformitarian Sir Charles Lyell current earth processes are the same as those in the past e g Bryce Canyon Utah Darwinian Evolution Charles Darwin and Alfred Wallace created a theory to explain change the origins of species and natural selection principles variation exists inheritance variation is heritable differential survival and reproduction struggle for existence conclusion biological change natural selection those forms most successful at reproducing in specific environments are selected no two individuals in a species are identical and offspring resemble their parents superior fitness ability to reproduce successful and surviving offspring specific environments environmental niches created adaptation series of beneficial characteristics Darwinian evolution does NOT claim we evolved from monkeys or use and disuse inheritance of acquired characteristics Evolution does not always mean progressive changes or require increased complexity Natural selection works on the most fit environments change and lead to species that no longer fit e g Guam rail birds disappeared after the introduction of brown snakes predators GENETICS and EVOLUTION Darwin s missing keys mechanisms of inheritance origin of variation and population genetics Mendelian Genetics Gregor Mendel hybridization experiments with pea plants found that heredity units factors determined by discrete inherited particles genes and the organism gets one factor from each parent principles of heredity segregation one factor from each parent dominance and recession independent assortment and recombination Chromosome Theory of Inheritance introduced the terms chromosomes alleles homozygous heterozygous genotype phenotype genetic inheritance uses Punnett Squares to determine phenotypes of offspring by multiplying factors dominant genes are capitalized recessive genes are lower case e g trait eye color B brown dominant gene b blue recessive gene father is BB and mother is bb all offspring would have brown eyes B B b Bb Bb b Bb Bb e g B brown b blue g green father is Bb and mother is gg half offspring would have brown eyes and other half have equal chances of green or blue eyes g g B Bg Bg b gb gb simple discrete traits one gene controls e g tongue rolling attached earlobes complex polygenic traits multiple genes control e g skin collor BIOCHEMICAL GENETICS Darwin nor Mendel knew where traits come from cell division mitosis regular cells meiosis sex cells crossing over during meiosis chromosomes intertwine and exchange segments of DNA mutations random change in DNA molecules ultimate source of all new variation two types chromosomal rearrangement and base substitution inheritance in pea plants PP purple dominant pp white recessive F1 generations hybrids F2 generation 3 purple 1 white genetic evolution change in allele frequencies in a population over time POPULATION GENETICS Four Forces of Microevolution natural selection mutations provide variety on which natural selection can work e g Down s and Kleinfelter s Syndrome point mutations single base pair original S allele of hemoglobin original LAC P allele lactose digestive capacity random genetic drift change in allele frequencies due to chance increases speciation founder effect group of individuals leave one population to join another e g The Dunkers ABO blood type people similar to Amish and Quakers fled Germany to go to the U S