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General Biology: Core Evolution Concepts

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  • Evolution

    Change in allele frequencies in a population over time.

  • Natural Selection

    Process where individuals with advantageous traits survive and reproduce more, passing those traits on.

  • Synapomorphy

    A shared derived character linking an ancestor and its descendants.

  • Morphology

    Study of the form, structure, and configuration of organisms, used to understand evolutionary relationships.

  • Transitional Features

    Traits showing intermediate forms between ancestral and descendant species, illustrating evolution.

  • Vestigial Structures

    Structures that have lost original function through evolution but still persist, like whale hind leg remnants.

  • Fitness

    An organism’s ability to survive and reproduce, not just strength.

  • Adaptation

    A heritable trait that increases survival or reproduction in a specific environment.

  • Mutation

    Random change in DNA that creates new alleles.

  • Gene Flow

    Movement of alleles between populations through migration.

  • Genetic Drift

    Random changes in allele frequencies, especially in small populations.

  • Bottleneck Effect

    Population suddenly shrinks, causing reduced genetic diversity.

  • Founder Effect

    Small group starts a new population with different allele frequencies.

  • Hardy-Weinberg Equilibrium

    A population that is not evolving under conditions: no mutation, no migration, large population, random mating, no selection.

  • Hardy-Weinberg Equation

    \(p + q = 1\) and \(p^2 + 2pq + q^2 = 1\) describe allele and genotype frequencies.

  • Directional Selection

    Favors one extreme phenotype.

  • Stabilizing Selection

    Favors the average phenotype.

  • Disruptive Selection

    Favors both extremes over the average.

  • Speciation

    Formation of new species.

  • Allopatric Speciation

    Species form due to geographic isolation.

  • Sympatric Speciation

    Species form in the same geographic area.

  • Prezygotic Barriers

    Reproductive barriers before fertilization: temporal, behavioral, mechanical, gametic isolation.

  • Postzygotic Barriers

    Barriers after fertilization: hybrid inviability and hybrid sterility.

  • Homologous Structures

    Structures with common ancestry but different functions.

  • Analogous Structures

    Structures with similar function but different evolutionary origins (convergent evolution).

  • Phylogeny

    The evolutionary history of a species.

  • Cladogram

    Diagram showing evolutionary relationships among species.

  • Taxonomy

    Science of naming and classifying organisms.

  • Binomial Nomenclature

    Two-part scientific name: Genus species.

  • Endosymbiotic Theory

    Eukaryotic cells formed when prokaryotes lived inside other cells, leading to mitochondria and chloroplasts.