Principle Figures in History of Evolutionary Thought:Carl Von Linne (1707-1778)Creationist-considered all species made by GodProponent of the Principle of the Fixity of Species- species are immutable/unchangeable after their creationJean Baptiste Lamarck (1744-1824)Theory of Inheritance of Acquired Characteristics (Theory of Use and Disuse)Tenants/ Propositions of this theoryAll Organisms have “needs” to surviveThese “needs” are satisfied by the use and modification of existing organs or by the production (or development) of new organsContinued use of organs leads to an increase in size and complexity (disuse leads to a reduction in size and their loss)These changes that occur during one’s lifetime are inheritable and can be passed down to one’s offspringGeorges Cuvier (1769-1839)Theory of Catastrophism- In the past, there were violent geological and climatic events that cause the extinction of species in the effected areas. After the cataclysmic event subsided, species from neighboring areas migrated into the areas. The immigrant species were similar to those that went extinct but were not identical.Charles Lyell (1797-1875)Theory of Uniformitarianism – forces acting today that shape the Earth are the same forces that acted in the past.Thomas Malthus (1766-1834)Essay on the Principle of Population – population size increases exponentially whereas food resources increase linearlyCharles DarwinTheory of Natural Selection- explains how a species changes over timeGalapagos Islands- studied animals and developed questions about differences in species.On the Origin of Species published in 1859.Tenants of Darwin’s Theory of Natural Selection:Reproductive potential of a population is high, but actual population size remains the same.Resources in the environment are in limited supply; individuals within a population compete for the resources.Biological variation in a population is normal.Any hereditary variation that allows any organisms even a slight advantage in competition for resources will be perpetuated. (Survive, live longer, pass down traits) Those with favorable traits will survive and produce more offspring that those without the favorable trait. Over time, there will be an increase in frequency of the favorable traits in the population.Suggested Pan Genesis Theory- representative cells from organs were stored in ova and sperm and were passed to childrenAlfred Russell Wallace (1823-1913)He also (in addition to Darwin) proposed species change by natural selection (he did not use the phrase “natural selection”)Gregor Mendell (1822-1884)The results of his pea plant experiment were published in 1866Round vs. Wrinkled seed (of a pea plant)Pollinated strictly round plants with strictly wrinkled seeds for the parental generations1st Generation (after parental)- 100% RoundMade from Round x Round2nd Generation-75% Round, 25% WrinkledSee notebook for genetics notes (Punnett Squares, etc.)Terms to Know (Reproduction/ Genetics)Principle of Segregation- Genes occur in pairs in an individual organism. In the production of sex cells, the pair of genes is separated. Each sex cell has one gene of the pair.Gene- Segment of DNA that codes for a protein.Allele- Alternative form of the same geneGenotype- Set of genes possessed by an individualPhenotype- Physical manifestation of the genotype or physical characteristicsHomozygous- Having two copies of the same alleleHeterozygous- Having one copy each of different allelesDominant Allele- Expressed phenotypically in both homozygotes and heterozygotesRecessive Allele- Expressed phenotypically only in a homozygotePrinciple of Independent Assortment- Segregation of one pair of genes does not influence the segregation of other pairs of genesThere is more genetic variability than phenotypic variability in a species.Homologous Chromosomes have the same sequence of genes.Interphase of Meiosis and Mitosis:Genes are activeChromosomes replicate (duplication)Chromatids – identical strands of DNACentromere – constricted portion of a chromosome that holds two chromatids togetherMitosis:Metaphase:Chromosomes align independently from one anotherAnaphase:Centromeres divideTelophase:Two cells are producedResults:Two cells are produced; each cell has the diploid chromosome numberDiploid – full complement of chromosomesBoth daughter cells are genetically identical to the parent cell and to each otherThe ultimate function of mitosis is in the production of cells that are genetically identical with the parent cellMeiosis (after interphase):Sex cells are produced by meiosisThe function of meiosis is the production of sex cells to transmit genetic material to offspringProphase I:Homologous chromosomes synapseSynapse – pairing of homologous chromosomesCrossing over – exchange of genetic material between homologous chromosomesMetaphase I:Homologous chromosomes remain paired with one another; nonhomologous pairs of chromosomes align independently from one anotherAnaphase I:Centromeres do not divideTelophase I:Two cells are formed (goes into Prophase II)Prophase II:Same as Telophase IMetaphase II:Chromosomes align independently from one anotherAnaphase II:Centromeres divideTelophase II:Four cells are formedResults:Four cells are produced; each cell has the haploid chromosome numberHaploid – one half of the chromosome numberEach daughter cell is genetically different from the parent cell and from one anotherUltimate function of meiosis is the production of genetically variable sex cellsMitosis versus Meiosis:Number of daughter cells: Two in mitosis; Four in meiosisNumber of chromosomes in daughter cell: Diploid for mitosis; Haploid for meiosisGenetic structure of daughter cell versus parent: Identical in mitosis; different from parents and one another in meiosisFunctional result: Exact genetic duplication for mitosis; (virtually) infinite genetic variability among daughter cells for meiosisReplication (duplication) of a chromosome: 2Replication occurs during interphaseWhen a chromosome replicates, two chromatids are produced, and the chromatids are held together by a centromere.A chromosome is made up of DNA; replication of a chromosome is the same as replication of DNADNA is a double helical moleculeDNA is composed of nucleotides.A nucleotide consists of phosphoric acid, sugar, and a baseFour bases:AdenineCytosineGuanineThymineReplication – semi-conservation; each DNA strand acts as a template (i.e. master strand for copying) for the