Important contributors to the progression of scientific thought their contributions Hutton Principle of Uniformitarianism Lyell Geological features are the result of small changes over a long time Kelvin Cooling experiments indicate greater antiquity of Earth Linnaeus Binomial taxonomy Cuvier Introduction of comparative anatomy Catastrophism Lamarck First theory of evolution acquisition of inherited features Malthus Resource competition the struggle for survival Darwin The Origin of Species and evolution by natural selection De Perthes Great antiquity of humanity based on stone artefacts Wallace Independently developed idea of natural selection Natural selection 5 theories of evolution Species change All organisms share a common ancestry Evolution is gradual Evolution leads to speciation Evolution occurs through Natural Selection The 3 necessary sufficient conditions for evolution by natural selection Variation in a trait Genetic inheritance of the trait Differential reproductive success The 3 modes of natural selection Stabilizing selection Directional selection Disruptive selection Focus on populations instead of individuals Natural selection cannot be goal oriented Natural selection optimizes long term reproductive success instead of maximizing short term reproductive success This demonstrates that there are no perfect adaptations Instead adaptations are almost always the result of a trade off between costs and benefits Examples of such trade offs are found in both Resource Defense Polygyny and Female Defense Polygyny Incorrect interpretation of the tenets of natural selection results in Evolution progress Natural selection favors those individuals that are stronger better fitter Naturalistic fallacy Genetics Mitosis Meiosis Mitosis somatic cells diploid Meiosis sex cells haploid Crossover recombination occurs during meiosis and is the exchange of genetic material between homologous chromosomes Crossover produces new combinations of alleles by reshuffling the genetic material Terminology Gene vs locus vs allele Genotype vs phenotype Heterozygous vs homozygous Dominant vs recessive vs codominant Mendelian inheritance Observed characteristics are determined by genes alleles Expression of genes in the individual is dependent on whether the allele is dominant recessive or codominant During fertilization alleles from both parents are joined to form a pair Each gene is equally likely to be transmitted Genes that code for different traits assort independently of each other Mutation Defined as a change in DNA Mutations are the only source of new variation Mutations are predominantly neutral or negative Mechanisms of Evolution Evolution is a change in allele frequencies in a population over generations Mechanisms of Evolution Random mechanisms Mutation Gene flow Genetic drift Non random mechanisms Natural selection Random mechanisms of evolution can lead to evolution but does not produce adaptations Speciation Speciation bridges micro and macro evolution Micro evolution occurs through the four mechanism of evolution Macro evolution is the process of speciation above the species level Speciation is a process instead of an event Speciation occurs through reproductive isolation which occurs through Mate choice Mating mechanisms Separation in time space and social behavior Species concepts Biological Species Concept Ecological Species Concept Species Mate Recognition Concept Types of speciation Allopatric speciation geographic isolation Parapatric speciation Sympatric speciation Phylogeny Homology ancestry convergence analogy Proper assessment is dependent on the scale at which it is examined Cladistic relationships between organisms are best studied using shared derived traits Phylogeny the evolutionary history of groups Grades vs clades Grades taxon united by a level of morphological complexity Clades group consisting of its species and all of its descendants Human Adaptation Variation Many traits are influenced by both genes and other factors Heritability proportion of variance in a trait explained by genetic factors Norm of Reaction genetically identical individuals express traits differently in different environments Race vs population Although humans vary across space in ways that cannot be meaningfully classified into different races human populations vary in time and space in ways that 1 represent genetic adaptations to local conditions and or 2 reflect different environments e g literacy healthcare etc
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