The Origin of Species: Biological Diversity and Speciation

These flashcards cover key vocabulary related to the origin of species, biological diversity, and mechanisms of speciation.

Microevolution

The change in the gene pool of a population from one generation to the next.

Speciation

The process by which one species splits into two or more species.

Biological species concept

Defines a species as a group of populations whose members have the potential to interbreed in nature and produce fertile offspring.

Reproductive isolation

Prevents genetic exchange (gene flow) and maintains a boundary between species.

Morphological species concept

Classifies organisms based on observable physical traits.

Ecological species concept

Defines a species by its ecological niche, focusing on unique adaptations to particular roles in a biological community.

Phylogenetic species concept

Defines a species as the smallest group of individuals that share a common ancestor and form one branch of the tree of life.

Prezygotic barriers

Reproductive barriers that prevent mating or fertilization between species before the formation of a zygote.

Postzygotic barriers

Reproductive barriers that operate after hybrid zygotes have formed.

Allopatric speciation

Speciation that occurs due to geographic isolation of populations.

Sympatric speciation

Speciation that occurs without geographic isolation, often due to factors like polyploidy or habitat differentiation.

Polyploidy

The condition of having more than two complete sets of chromosomes, often leading to speciation in plants.

Adaptive radiation

The evolution of many diverse species from a common ancestor, often observed in isolated island chains.