ANTH 1013 1st Edition Lecture 3 Outline of Last Lecture I. Evolutionary theoryII. How do we explain the diversity of life on earth?III. Early attempts at ordering the worldIV. Fixity of SpeciesV. Organizing the diversity of lifeVI. How old is the earth?VII. Making sense of fossilsOutline of Current Lecture I. Charles Darwin and the voyage of the HMS BeagleII. Alfred Russel Wallace (1823-1913)III. Origin of Species – DarwinIV. Natural SelectionV. Artificial SelectionVI. Theories of HeritabilityVII. Johan Gregor Mendel (1822-1884)Current LectureI. Charles Darwin and the Voyage of the HMS Beaglei. One of 6 children of affluent parents, originally studied medicine at the University of Edinburgha. Completed his degree in ministry at Cambridgeb. Influenced strongly by John Henslow, who invited him on the voyage of the beagleii. The Voyage of the HMS Beaglea. He was the “gentleman amateur naturalist” AKA he keeps the captain companyb. 1831-1836c. Biological significance:1. Collected living animals for study in England2. Observed similarities of fossils from S. America to similar species in S. America living today3. Witnessed an earthquake in ChileThese 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.4. Observed sea shells far inland and inferred that rock beds below the sea were elevated to form mountainsiii. Post-Beaglea. Marries (his cousin) and has many children, some of which died early in lifeb. Settled in “Down House” in London, where he has a green house where he conducted his studiesc. His daughter dies and he is distraught, wondering if she died because he reproduced with his cousind. Publishes a book on his journey on the HMS Beagle, becomes an expert on barnaclese. Created the first tree of lifeII. Alfred Russel Wallace (1823-1913)i. Field biologist in Indonesia, father of biogeographya. Observes how life is organized geographicallyii. 1858 – Sent Darwin a draft of his own version of the theory of natural selection for his feedbacka. Darwin says it is as if Wallace had his own manuscript, they are the same theoryb. Joint Darwin-Wallace presentation given before the Linnean Society of London announcing both theories simultaneously in 1858III. Origin of Species - Darwini. Published in 1859 – immediately sold out, 6 editions published from 1859-1872a. Full title: On the Origin of Species by means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life1. Let the strongest live and the weakest die2. Presented idea of extinction, but with common ancestorsIV. Natural Selectioni. Thomas Malthus wrote essays on human population growth that stimulated Darwin to develop his theory of natural selectionii. “Multiply, vary, let the strongest live and the weakest die.” – Darwin, The Origin of Speciesa. Observation 1: populations can expand indefinitely, but resources are limitedb. Observation 2: Populations in nature are roughly stable, more offspring are born than survive to reproducec. There must be a “struggle for existence”iii. If there is a struggle for existence, what factors determine which individuals survive?a. Observation 3: Individual variation within populations affects ability to acquire resourcesb. Observation 4: Variation is heritable – offspring inherits these variationsiv. Natural selection = differential survival and reproductive success AKA natural selectiona. Observation 5: environment is constantly changingb. Populations will adapt to their environments via natural selectionv. Survival of the Fittesta. If more offspring are produced than survive, those that survive because theyare more fit, (better able to compete for resources) will leave behind more offspringb. These offspring will resemble their parents and will also tend to leave behind more offspringc. Over time, the population will adapt to the changing environmentvi. The Theory of Evolutiona. Darwin does not eliminate God, he simply states that life comes from some source of powerV. Artificial Selectioni. Darwin compared natural selection to artificial selection which he was able to directly observea. Looks at pigeons, dogs, and other animals to theorize that humans are artificially shaping certain animals’ breedsVI. Theories of Heritabilityi. Antonie van Leeuwenhoek (1632-1723)a. Father of microbiology, made improvements to the microscope, discovered spermb. Proposed Homunculus Theory (Preformationism)1. Preformationism: inside sperm is a tiny person ii. Inheritance of acquired characteristicsa. Jean-Baptiste Lamarck – a trait acquired by an animal during its lifetime can be passed on to offspringiii. Pangenesisa. Theory proposed by Darwin, says that each body has a different particle1. Pangenes are produced by organs, particles of man and woman “blend” togetherb. Blending inheritance: a form of inheritance in which the features of offspring are the average of those seen in parentsc. IT IS WRONG – we are not all identical to our siblings!VII. Johan Gregor Mendel (1822-1884)i. Trained in botany at U of Vienna, was an Augustinian monkii. Mendel’s experiments:a. Used garden peas as a model: self fertilizing, bred “true”, variants easy to observeb. First generation cross: green + yellow = 100% yellowc. Second generation cross: yellow + yellow = 75% yellow, 25% greeniii. Mendel’s law of segregationa.Particles (AKA genes) do not blend!b. Both parents contribute hereditary material equally to the offspring1. Traits must be represented by pairs (one from each parent)c. Genes come in different forms (alleles)d. Each copy “segregates” into a different sex cell (gamete)iv. Terms to know:a. Phenotype: the observable expression of the genotypeb. Genotype: the genetic makeup of an individualc. Allele: alternate forms of a gened. Homozygous: the same allele at a single locuse. Heterozygous: two different alleles at a single locusf. Recessive: an allele that isn’t expressed in a heterozygoteg. Dominant: an allele that prevents the expression of a recessive allele in a