Evolution Midterm Ultimate Study Guide

Evolutionary Thought

The historical process of evolution and its scientific understanding, significantly predating Darwin.

Key Contributors to Evolutionary Theory

Figures such as Malthus, Hutton, Lyell, Lamarck, Linnaeus, Cuvier, Wallace, and Mendel whose work laid the groundwork for evolution.

Essentialism

A belief that species are immutable and created to occupy fixed positions in a hierarchy, as proposed by Aristotle.

Scala Naturae

Aristotle's concept of a ladder of life where all living beings are organized hierarchically.

Malthusian Catastrophe

A theory by Malthus suggesting that population growth would surpass food production leading to famine and societal challenges.

Natural Selection

A mechanism proposed by Darwin and Wallace where individuals with advantageous traits reproduce more successfully.

Adaptive Radiation

Rapid evolutionary diversification of an ancestral lineage into various forms adapted to different environments.

Gene Flow

The transfer of alleles between populations which decreases genetic differentiation.

Hybrid Zone

Regions where different species meet and interbreed, producing hybrids.

Hardy-Weinberg Equilibrium

A principle stating that allele frequencies in a population will remain constant in the absence of evolutionary influences.

Speciation

The evolutionary process where a species splits into two or more distinct species.

Biological Species Concept

A definition of species focusing on the potential to interbreed and produce viable, fertile offspring.

Prezygotic Barriers

Reproductive barriers preventing mating or fertilization between species.

Postzygotic Barriers

Barriers that prevent viable, fertile offspring after fertilization has occurred.

Directional Selection

A mode of natural selection that favors phenotypes at one extreme of the trait spectrum.

Disruptive Selection

Natural selection that favors individuals at both extremes of the phenotypic range.

Stabilizing Selection

Natural selection that favors intermediate phenotypes and reduces variation.

Microevolution

Change in allele frequencies in a population over generations, regardless of the driving mechanism.

Genetic Drift

Random fluctuations in allele frequencies in a population, significantly impacting small populations.

Bottleneck Effect

A sharp reduction in a population's size leading to decreased genetic diversity.

Autopolyploidy

Chromosome duplication within a single species, leading to new species through errors in cell division.

Allopolyploidy

Hybrid speciation arising from interspecific hybridization followed by chromosome duplication.

Continental Drift

The movement of Earth's tectonic plates leading to the geographical reconfiguration over geological time.

Mass Extinction

Widespread and rapid decrease in biodiversity on Earth, often resulting in the loss of many species.

Phylocode

A system of classification that emphasizes evolutionary relationships and common ancestry.

Dichotomous Key

A tool for identifying species based on a series of choices between two alternative characteristics.

Molecular Barcoding

The use of DNA sequences to identify species and assess biodiversity.

Cladistics

A method of classifying species based on the construction of phylogenetic trees, emphasizing shared derived characteristics.

Monophyletic Group

A clade that consists of an ancestor and all its descendants.

Analogy (Homoplasy)

Trait similarity resulting from convergent evolution, not from a common ancestor.

Homology

Trait similarity due to shared ancestry.

Fisherian Runaway Hypothesis

A theory of sexual selection suggesting that females may choose mates based on extravagant male traits.

Good Genes Hypothesis

A theory suggesting that certain traits serve as honest signals of superior genetic quality during mate selection.