Biogeography and Evolutionary Concepts

Flashcards for key vocabulary and concepts related to biogeography and evolutionary mechanisms.

Peninsular Effect

Species richness tends to decrease from continental interior toward terminus of peninsula due to the island-like nature of peninsulas.

Rapoport’s Rule

Toward poles, area of range increases, overlap of ranges increases, and species richness decreases.

Bergmann’s Rule

Body size of endotherms tends to increase with latitude.

Allen’s Rule

In endothermic vertebrates, those living in hotter environments have longer appendages.

Gloger’s Rule

Darker colors occur in more humid environments.

Elevational Gradients

As elevation increases, air temperatures and pressure decrease.

Tuatara

A lizard found in New Zealand known as a living 'time capsule'.

Allopatric Speciation

Speciation that occurs when a barrier separates a population, preventing free interbreeding.

Sympatric Speciation

Speciation that occurs within a single geographical area without barriers.

Glaciation

The process where land is covered by glaciers from compacted snow.

Dispersal

Movement of individuals away from their birthplace; a rare and random process.

Active Movement

Movement by an organism's own power.

Passive Movement

Movement carried out by wind, currents, or other organisms.

Vagility

Ability to move distances; varies by taxa.

Jump Dispersal

Crossing wide barriers via methods such as flying or floating.

Diffusion

Steady expansion of species too rapid for evolution.

Secular Migration

Spread so slow that species undergo evolution.

Corridors (dispersal)

Unselective routes that permit the spread of many taxa.

Filters (dispersal)

Selective connections often acting as transition zones between biogeographical regions.

Sweepstakes (dispersal)

Random and rare means of dispersal resulting in unselective species transfer.

Vicariance

The process whereby geographical barriers lead to speciation.

Panbiogeography

Concept involving centers of origin where species spread to now occupied areas.

Barrier

A biotic or abiotic feature that restricts the movement of organisms to new locations.

Speciation

The formation of new species.

Morphological Species Concept

Classification based on distinguishing physical traits.

Biological Species Concept

Species defined by the ability to interbreed and produce fertile offspring.

Evolutionary Species Concept

Each independent lineage is recognized as a separate species.

Phylogenetic Species Concept

Species that share unique, derived characters.

Subspecies

Populations that are genetically and morphologically distinct.

Variety

Used mostly for plants to denote variation in traits, not based on genetic distinction.

Ecotype

Distinct populations adapted to specific habitats.

Race

Geographically distinct groups within a species.

Evolution

Change in gene frequency within a population over time.

Hardy-Weinberg Principle

Mathematical model (p^2 + 2pq + q^2 = 1) describing genetic equilibrium.

Macroevolution

Large-scale evolutionary changes, including speciation and extinction.

Microevolution

Small-scale evolutionary changes within populations.

Areography

Study of the spatial distribution of organisms.

Genetic Drift

Random changes in gene frequency, especially in small populations.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Gene Flow Immigration

Introduction of new genes from new arrivals to an existing population.

Gene Flow Emigration

Removal of genes from the existing population through departing individuals.

Competitive Exclusion

When two coexisting species using the same resources lead to one outcompeting the other.

Biogeographic Corollary

Species in different areas tend to use resources similarly, while those in the same habitat tend to differ.

Adaptive Radiation

Process where a species diversifies into new forms adapted to different environments.

Convergent Evolution

Unrelated organisms evolve similar traits independently due to similar environments.

Parallel Evolution

When multiple species evolve similar traits due to sharing common ancestors.

Red Queen Hypothesis

The idea that species must continually adapt to survive due to co-evolution.

Overkill Hypothesis

Theory that human activities led to the mass extinction of large extinct animals.

Extinction

The complete disappearance of a species.

Endemism

When a species is unique to a specific location and not naturally found elsewhere.

Cosmopolitan

Species that are widely distributed around the world.

Provincialism

Endemic forms with a clumped distribution.

Therapsids

The first mammals that appeared alongside the dinosaurs.

Disjunction

Distribution pattern where closely related species are found in widely separated areas.

Wallace’s Line

A boundary separating distinct Australian and Asian fauna.