Exam sheet

Allopatric Speciation

Speciation that occurs when populations become geographically isolated, preventing gene flow and leading to independent evolution.

Sympatric Speciation

Speciation that occurs when populations in the same geographic area diverge into separate species due to reproductive barriers without physical separation.

Geographic Isolation

A key aspect of allopatric speciation that involves a physical barrier separating populations.

Polyploidy

The condition where an organism has more than two complete sets of chromosomes, often leading to speciation.

Autopolyploidy

Polyploidy that results from the doubling of chromosome number within a single species, leading to reproductive isolation.

Allopolyploidy

Polyploidy that involves hybridization between two species followed by chromosome doubling, allowing the hybrid to become fertile.

Prezygotic Barriers

Reproductive barriers that prevent mating or fertilization before a zygote is formed, such as temporal and behavioral isolation.

Postzygotic Barriers

Reproductive barriers that occur after fertilization, including hybrid sterility and hybrid breakdown.

Reinforcement

A process in hybrid zones where hybrid offspring are less fit than parent species, leading to stronger reproductive barriers.

Punctuated Equilibrium

A theory suggesting that species remain stable for long periods until brief periods of rapid evolutionary change occur.

Species Richness

The number of different species present in a given area.

Species Evenness

The relative abundance of each species in a community.

Mass Extinction

A significant, global decrease in biodiversity occurring over a relatively short period.

Habitat Fragmentation

The process of dividing large habitats into smaller, isolated patches, negatively affecting species survival.

Biomagnification

The process where toxic substances accumulate at higher concentrations at higher levels of the food chain.

Invasive Species

Non-native species that disrupt local ecosystems and outcompete native species, contributing to biodiversity loss.

Phenotypic Plasticity

The ability of an organism to change its phenotype in response to environmental conditions.

Biophilia

The innate human affinity for nature and living systems, emphasizing the importance of conserving biodiversity.

Conservation Biology

The scientific study aimed at protecting species, their habitats, and ecosystems from excessive rates of extinction.

Umbrella Species

A species whose conservation efforts also protect many other species due to its habitat requirements.