7. The theory of organic evolution: Evolution is the central, unifying theory of modern biology.
Darwin and the Origin of Species by Natural Selection:
         1.- Life is old: Was not created but evolved from previously existing organisms
         2.- Life started with simple organisms and became more complex with time
         3.- Natural Selection is the force that drives evolution

    a. Natural Selection
    b. The Genetic Basis of Evolution: Mutations
    c. The level at which evolution takes place
        i. Species (interbreeding)
        ii. Population (genetic variation)
        iii. Individuals (single)
    d. The Mechanisms of Evolution:
        i. Variation
        ii. Natural Selection
        iii. Isolation: Geographic distribution of organisms
    e. Modes of speciation
        i. Phyletic evolution: Gradualism, slow change; evol. horses -MICROEVOLUTION
        ii. Punctuated equilibrium: Rapid change
    f. Extinctions
        i. Causes of extinction
            1. Physical:
                a. local environmental change
                b. climate change
                c. extraterrestrial causes
            2. Biological:
                a. increased predation
                b. new predator or disease
                c. humans
    g. Patterns of Evolution
        i. Divergence: new species (speciation)
        ii. Convergence: groups develop similar-looking characteristics
            1. Homologous (structure evolves from similar ancestral feature)
            2. Analogous structures (similar functions, dissimilar origins)
        iii. Parallel evolution: unrelated lineages undergo similar evolutionary changes through time.
        iv. Speciation: Adaptive radiation and mass extinction. Speciation is caused by reproductive barriers
            1. Physical reproductive barriers:
                a. mountain range
                b. boundary between ocean layers
            2. Biological reproductive barriers:
                a. differences in mating behavior
                b. incompatibility of egg and sperm
                c. differences in reproductive timing
        v. Radiation: rapid origin of many new species from a single ancestral group