ANTH 120 1st Edition Lecture 3 Outline of Last Lecture I. What Is Science?II. How do we do science?III. The Scientific MethodIV. TheoryV. History of Evolutionary Thinkinga. Important Scientists and their Contributionsb. Hutton and Lyell  Uniformitarianism…old earthc. George Cuvier Catastrophism… Animals can go extinctd. Robert Hook  Fossils were once livinge. Carlos Linneaus  Binomial Nomenclature (taxonomy)VI. How do Humans fit in?Outline of Current Lecture VII. Context for Darwin’s IdeaVIII. Darwin’s BIG Idea: Contribution to Evolution  Natural SelectionCurrent LectureDemography: the study of statistics such as births, deaths, income, or the incidence of disease, which illustrate the changing structure of human populations.Thomas Malthus (1766-1834): all humans have potential for explosive population; population islimited by food supply; members of population compete for food Populations are limited by food supply and whether there is enough food for everyone or not-Malthus saw how London was divided into different socioeconomic classes and some families did not have access to funds for food Observed: all humans have potential for explosive population growth, but populations are roughly stable Deduction: 1) Populations are limited by their food supply 2) Members compete for foodThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Evolutionary Biology: how organisms change over timeEvolution  Change in gene frequency, in a population, over timeJean-Baptiste Lamarck (1774-1829): Evolutionary Biology-Inheritance of acquired Characteristics (Lamarckism): -Change anatomically in response to new demands or needs. -Pass on to offspring-Example: Giraffes… There is a little short giraffe surrounded by tall trees, so slowly the little giraffe stretches it neck in order to get food to survive. Darwin’s Big Idea: Natural SelectionCharles Darwin (1809-1882):-Ideas formed on HMS Beagle: Darwin’s Voyage (1831-1836) H.M.S. Beagle with Captain Fitzroy-Biological Variation is KEY  there is lots of variation in any population, the variation is important because it is going to dictate how the environment will work with the population-Recognized the importance of sexual reproduction in increasing variation -At every single port during there voyage Darwin would go onto land and collect many samples and ship back to the Natural History Museum in London-Galapagos Islands: each island had variations of the same animals-Galapagos Island Finches  Darwin started to notice that the birds generally looked thesame, but there were still differences within each bird-The beaks that each finch had were specific to the specific terrain of the islands that they were found on -Variation is NOT random-Adapted to eat particular foods and live in particular environments-Physical features allowed them to survive and reproduce-Traits selected by natureGalapagos’ Tortoise Phenotype Varied by Island-Long necked tortoises vs. short necked tortoises that varied with the type of foliage that was found on the specific island-Shell shape “fit” their particular environmentAdaptive Radiation: All variations descended from a small number that came to the island a long time ago-EX: Domestic breeds of Dogs take their origin from the WolfNatural SelectionWhat Did Darwin Actually Do?Hypothesis: some variations are favored, some disfavored, … favored traits are passed to offspring… over time the result is formation of new species… Natural SelectionProcesses of Natural Selection:1) Species are going to produce offspring faster than food supply increases2) Natural biological variation3) In each generation, more individuals are produced than can survive4) Individuals with favorable traits produce more offspring5) Environment determines whether a trait is beneficial6) Traits are inherited and passed on to the next generation7) Variations accumulate over long periods of time, so later generations may be distinct from ancestral onesExamples of Natural Selection:The Peppered Moth  there were white Birch trees and the moths stood out with their black coloring, birds would often eat the moths -Generations change to make adaptations to have a greater chance of survival -Trees were originally white and then after the industrial revolution the trees became darker thus the moths adapted to survive so their color of their wings changed from being white to being blackish grey3 Prerequisites needed for Natural Selection to Occur:1) Trait is heritable2) Trait shows variation between individuals3) Environment exerts pressure on population Natural Selection = “Survival of the fittest” = WRONGNatural Selection = “Reproduction of the fittest” = CORRECT-Evolutionary Fitness is the differential reproductive success  more offspring Darwin’s Accomplishments1) Species are NOT static entities… change through time!2) Natural selections is the chief mechanism3) Variation is inherent in ALL populations4) Natural Selection works on variation5) Humans are a part of nature, not apart from natureDarwin-Wallace: Theory of Evolution by Natural SelectionCharles Darwin was the first person to explain the basic mechanics of the evolutionary processAlfred Russell Wallace independently reached the same conclusions at Charles Darwin!Synthetic Theory of Evolution-All evolutionary phenomena can be explained in a way consistent with know genetic mechanisms and the observational evidence of naturalists.-Evolution is gradual: small genetic changes governed by nature and natural selection-Natural Selection is the main mechanism of change; even slight advantages are important when continuedDarwinian Evolution + Genetics = New-Darwinian Evolutionary Theory 4 Forces of Evolution: How does variation arise?1) Natural Selection2) Mutation3) Gene Flow4) Genetic DriftNatural Selection: individuals with advantagesPredation: eat or to be eaten-Avoid predators in space and time (example: monkeys in trees to avoid the lions)-Live in groups: fight predators off which decreases chance of being eatenSexual Selection: “the result is not death to the unsuccessful competitor, but few or no offspring.”-Intrasexual (male-male): males intimidate other males thus deterring or defeating rivals-Intersexual (mate choice): males make themselves attractive to the opposite