Darwin didnt know sources of variation mechanisms of

This preview shows page 17 - 23 out of 52 pages.

°Darwin didn’t know:Sources of variationMechanisms of heredity°Gregor Mendel:Dominant and Recessive TraitsoDominant will prevailBig AoRecessive will most likely not prevailLittle aoHeterozygousAa: Heterozygous different allelesoHomozygous
AA or aa: Homozygous same allelesoHomozygous dominant:AAoHomozygous recessive:aaGenotype and PhenotypeGenotype: hereditary make-upPhenotype: expression of traitsNatural Selection works on Phenotype (traits that are expressed), not on GenotypePrinciple of independent assortment: Chromosomes are inherited independently of one anotherAlbinoGenes that cause albino can also cause neurological effectsPopulationGene Pool: the sum of all the genetic material in a breeding populationGenetic Equilibrium: gene pool remaining constantGenetic evolution: change in a population’s gene pooloMechanisms of Genetic Evolution:1. MutationChanges in the DNA
Spontaneous MutationInduced MutationPopulation Size:2. Random Genetic DriftLoss of a trait through chanceoFounder Effect: Drift, but not randomOne Segment of a population founding a new population3. Gene FlowExchange of genes between populations through mating (immigration)Non-random matingoConsanguineous mating (mating with people with their same blood, brother date sister type thing)Culture influences how genes are exchanged4. Natural SelectionMost powerful mechanismEpigenetics: changes in the expression and function of genes without alterations in the DNA sequenceoEpigenetic marks tell genes to switch on and offoSome Epigenetic changes are heritable, and affect future generations°Nazi’s embraced Mendelian genetics and focused on breeding°Communism stressed the role of environment and education, embraced Lamarck °Nettie Stevens, PH. DDiscovered the XY chromosomes°Charles Drew, M.DDeveloped the first blood bank
Anthropology 10110/01/2017°Natural selection directs change in a particular way
°Genotype: Genetic make up°Phenotype: expression of genetic potential°*** Natural Selection works on Phenotype, NOT Genotype. ***°°Sickle-Cell Anemia – curved blood cell?They stick togetherThey clog up tiny vesselsThey die from 10 to 20 daysPain, serious & often fatal disease°HemoglobinNormal Allele: HbAoHbA hbAAbnormal Allele: HbSoHbS HbSSigns of Sickle Cell TraitoHbA HbSoSickle Cell trait was protected against malaria(An individual is more or less fit in the environment)Human Variation and Adaptation
Rule of HypodescentDescent: social identity on the basis of ancestryRule of Hypodescent: a child potentially a member of two groups will be assigned to the minority groupIf a baby is half black and half white, he will say he is blackWhen you check that little box on the papers of which race you are°Race in Brazil:No rule of hypodescentClassification based on phenotype

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture