Human Biological EvolutionPaleoanthropologyInheritance: Gregor MendalGametes: Genes & DNAInheritanceWhat is Evolution?Forces of EvolutionMutationsNon-Directional SelectionNatural SelectionHow does evolution lead to new species?ANTY 101 1st Edition Lecture 12Human Biological Evolution Genes, Bones, and Beliefs Paleoanthropology -subdiscipline of Biological Anthropology -Study of really old, ancient humans; and human ancestors -What types of scientific data are involved?• Fossils; morphology• Primates; biology, morphology, and behavior• Genomic sequences, DNA• Geology & Archaeology; stratigraphy, dating, tools, ect. -Systems of Knowledge • Religion & Belief • Understanding of Inheritance and Evolution Inheritance: Gregor Mendal -Cross breeding pea plants to get certain traits -Father of genetics (1866)• Dominant and Recessive ‘traits’ 1• Alleles -Alternate expressions of a gene-Each person has 2 alleles per trait -Phenotype• What we actually see expressed • A blood type-Genotype• What is apart of your genes: AO blood -Law of Segregation • You're not blending those traits into a new trait, they stay separate -Law of Independent Assortment• Genes inherited independently • Genetic Linkage-Punnett Squares-PTC Tasting • Taste stripsGametes: Genes & DNA-46 packages of DNA make up the chromosomes in cell nucleus• (23 pairs)2• Dogs have 39 pairs-GENE: a portion of DNA molecule that codes for a protein • DNA (deoxyribonucleic acid)-2 Base Pairs: Adenine— Thymine; and Guanine— Cytosine • Pairs form 20 Amino Acids• Example: A-T G-C G-C= one “word”• Proteins are “phrases” (3+ base pairs= multiple Amino Acids or words-Inheritance -DNA in Gametes-Chromosomes replicate-Cells divide twice• 4 daughter cells• 23 chromosomes each• Crossing over & recombination• Increases genetic variation• Errors and mutations What is Evolution?3-Evolution = changes in gene (trait) frequencies in populations from one generation to the next• Change in non-directional • not going from worse to better or simple to complex• rather chance, fitness, selection -Example of evolution : Diamond back moths in the industrial evolution Forces of Evolution -Non-Directional Selection (Chance) • Mutation and inheritance • Genetic Drift • Gene Flow • Always happening; work together and with selection -Directional Selection • Natural selection (sexual selection) • Human directed evolution -Selective Breeding -Domestication • Variation must already be present! (i.e. does not create NEW variation)Mutations 4-More mutations= more variation= more options to adapt -Happens to individuals • Can be advantageous, deleterious or neutral • Mutations are random• Point mutation vs. Chromosomal mutation • Stress increase mutation rates -5-100 mutation per million sex cells• Gamete mutations relevant for inheritance • Introduces variation to populations if inherited and passed on Non-Directional Selection -Gene Flow • interbreeding and migration; adds new genetic combinations -Genetic Drift • small population; “sampling error” of alleles (e.g. island colonies); founder effect • Genetic Bottleneck (e.e. Tsunami or Flu) Reduces a population temporarily to very low levels; reduces genetic diversity Natural Selection -Survival of the fittest • best adapted “environment” survive to pass on genes5• Variations/Mutations must exist in population • Much of it is chance!-Can be rapid; might not last (e.g. moths, finches)-Only relevant for adaptive variation -“Prime mover” of 4 evolutionary forces -Lack of variation—> extinction • Natural selection depends How does evolution lead to new species?-Species:• “Ability to interbreed & produce fertile offspring -“Reproductive Isolating mechanisms”• Seasonal mating and courtship behaviors • Mechanics or gamete incompatibility• Hybrids non-viability or sterility (1/2 dozen genes)-Population Isolation (divergence)-Species change to adapt over time
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