Evolution & Taxonomy Unit 7 Study Set

Aristotle

Believed species were fixed and organized them on the "Scale of Nature".

Carolus Linnaeus

Created modern classification and binomial nomenclature based on similarities.

Georges Cuvier

Proposed Catastrophism and demonstrated that extinction occurs via fossils.

Hutton & Lyell

Proposed Uniformitarianism; Earth changes gradually and is very old.

Jean-Baptiste Lamarck

Proposed inheritance of acquired characteristics and the principle of use/disuse.

Thomas Malthus

Proposed that populations grow faster than resources, leading to competition.

Artificial Selection

Humans choose organisms to reproduce to obtain desired traits.

Natural Selection

Environment determines favorable traits; advantageous traits lead to more reproduction.

Darwin's Observations

Individuals in a population vary; more offspring are produced than survive.

Darwin's Inferences

Favorable traits survive/reproduce more and become common over generations.

Adaptation

Inherited trait that increases an organism's survival and reproduction.

Selection Level

Natural selection acts on individuals, but evolution occurs in populations.

Fossil Evidence

Shows organism changes over time, extinction, and transitional forms.

Homologous Structures

Similar structures from common ancestry; may have different functions.

Analogous Structures

Similar function but different ancestry; result of convergent evolution.

Convergent Evolution

Unrelated organisms evolve similar adaptations due to similar environments.

Molecular Evidence

Comparing DNA/proteins; more similar sequences indicate closer relationships.

Gene Pool

All alleles present in a population.

Allele Frequency

How often an allele occurs in a population.

Hardy-Weinberg Equilibrium

Baseline state where no evolution occurs and allele frequencies are constant.

Microevolution

Change in allele frequencies within a population over generations.

Macroevolution

Large-scale evolutionary change including speciation and extinction.

Mutation

Change in DNA sequence; the ultimate source of genetic variation.

Sexual Reproduction (Variation)

Reshuffles existing alleles through meiosis and fertilization.

Genetic Drift

Random change in allele frequencies; most significant in small populations.

Bottleneck Effect

Genetic drift where a disaster drastically reduces population size/variation.

Founder Effect

Genetic drift where a small group starts a new, isolated population.

Gene Flow

Movement of alleles between populations via migration; reduces differences.

Directional Selection

One extreme phenotype is favored; population shifts in one direction.

Stabilizing Selection

Average phenotype is favored; extremes are selected against.

Disruptive Selection

Both extremes are favored; intermediate phenotype is selected against.

Biological Fitness

Measured by reproductive success and contribution to the next generation.

Intrasexual Selection

Competition within the same sex for mates (e.g., male vs. male).

Intersexual Selection

Mate choice (usually female choice of specific male traits).

Species

Organisms that can interbreed and produce fertile offspring.

Speciation

The formation of new species.

Temporal Isolation

Reproductive barrier where species breed at different times.

Behavioral Isolation

Reproductive barrier involving different courtship rituals or behaviors.

Mechanical Isolation

Reproductive barrier where reproductive structures are incompatible.

Gametic Isolation

Reproductive barrier where sperm and egg cannot fuse.

Geographic Isolation

Physical separation prevents gene flow, leading to independent evolution.

Adaptive Radiation

Evolution of many species from one common ancestor in different niches.

Binomial Nomenclature

Two-part scientific name: Genus (capitalized) and species (lowercase).

Linnaean Hierarchy

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Phylogenetic Tree

Diagram showing evolutionary history and relationships.

Clade

A group consisting of a common ancestor and all its descendants.

Derived Character

A trait unique to a particular clade.

Outgroup

Organism that diverged earlier; used as a comparison in cladograms.