Lecture 5 ANTH 160A1Outline of Last Lecture I. OriginsOutline of Current Lecture Culture HistoryCurrent LectureCahokia - case study in mound builders in the Mississippi valleyFranz Boas - Father of American anthropologyHistorical particularism: Reaction to unilinear cultural evolutionArgued to explore each culture in great detail, to understand its history and present condition. There are countless paths a culture may take, not one unilinear course.Historical Particularism dominated anthropology until the second half of the 20th century important to the development of American archaeologyContext of Culture HistoryWorks progress Admin. Excavations, James Griffin, Emil Haury, A.V. KidderMultilinear cultural evolutionSocieties evolve along their own coursessuccess (cultural survival) determined by abiliy to adapt to natural environmentTools of adaptation: technological development, developments in social organizationBands, Tribes, Chiefdoms, States (E. Service)Dependent on # of people, Movement (mobile or sedentary), Small and mobile-bandsSedentary lifestyle for most tribes which use agriculture. Chiefdoms - explosive population from tribes with domestication of plants and animals. Social hierarchy takes place in chiefdoms.Processual Models - Lewis BinfordCulture as Adaptation (e.g., environmental change and adaptations to it)Ecological TheoriesCultural evolutionary theories, evolutionary ecology. culture is adaptive to environmentEvolutionary ecology and human behavioral ecologyapplies theories and models from evolutionary ecologybased on natural selection and viewing humans as the result of evolutionary processesInvestigates - subsistence strategies, technological innovation, biohabitat alterations, evolution of domestication and agriculture, and on and on Archaeology Theory todayprocessual modelsexplain external factors for cultural change environmental change and adaptations to itEcological theories - cultural evolutionary theories, evolutionary ecologyPost processual modelsexplain internal factors for cultural change (human interactions, agency)Gender, trade and exchange, ideologies and beliefsIn reality both perspectives are takenFactors of Variation and EvolutionMayr - a species is a community of populations (reproductively isolated from others) that occupies a specific niche in nature.Or an interbreeding group of individuals able to reproduce fertile offspringHorse + Horse = HorseHorse + Donkey = Mule (not fertile)Problems with the species concept: Difficult when dealing with past generations: we can never know if an individual alive 1,000 or 10,000 years ago could reproduce with the same species today and produce fertile offspringGeographically isolated populations may be able to procreate and produce fertile offspring but they cannotBreeding population (Deme) - Groups of interbreeding individuals whom bear a part or small sample of the total species' gene pool.Gene Pool: The total number of combinations of all genesThe actual genetic composition will depend on: 1. the degree of interbreeding between populations 2. natural forces may alter the gene pool each generation.A/B/C/D/E/F/: Overlap of geographically adjacent groupsA could breed with F, but not always because of distance. Therefore those in the middle will have a better chance of transferring genes.Variation and evolutionEvolution = Change Descent with modificationLasting change in gene frequencies in a population from one generation to the nextEvolution = Punctuated equilibrium or gradualism?Eldredge and Gould proposed punctuated equilibrium or the idea that species will remain in stasis for most of their evolutionary history, but then will experience rapid speciation events resulting from a strong selective factorMendelian inheritance:Johann Gregor MendelRe-discovered 1900sA monk, he conducted experiments in garden peas resulting in 2 lawsLaw of segregation - when any individual produces gametes, the copies of a gene separate, so that each gamete receives only one copy.Law of independent assortment - Alleles of different genes assort independently of one anotherduring gamete formationRecallChromosome = single piece of coiled DNAGenes - gold the information to build and maintain an organism's cells and pass genetic traits to offspringGenotype - genes phenotype - what actually is expressedThere remained a problem understanding recessive and dominant alleles. Solved independentlyby G.H. Hardy and W. Weinberg in 1908In a hypothetical population where all is equal: p^2+2pq+q^2This scheme works for any singe loci genotype (Monogenic vs. polygenic)Hardy-Weinberg Law - the frequency of p and q will remain the same throughout any number ofgenerations given a stable, random-breeding population isolated from other populationsThat is in a population where evolution is not occurring (steady state equilibrium)This hypothetical population requires 5 assumptions:No mutations, natural selection is not operating, mating is random, there is no gene flow, population is infinitely large (eliminates chance of genetic drift)Mutation - is a change in the genetic code that introduces a new allele - ths is the ultimate source of all variationAll mutations are seen as an error in DNA coding with an effect on protein synthesis, but is all mutation bad? (lethal/detrimental but not lethal/beneficial)Natural selection - the sum total of all processes that determine survival and reproductionSpontaneous mutations - may confer an advantage in some environmental conditionsOr environmental conditions can change yielding a once advantageous trait disadvantageousCase study: The pepper moth - prior to industrial revolution no dark colored moth was recordedIndustrial revolution forced a significant increase in soot deposition in EnglandSoot darkened trees and rocks.Today 90% or more of the pepper moths are