Speciation and Macroevolution Vocabulary

Flashcards covering the vocabulary from the Speciation and Macroevolution lecture.

Morphological species concept

A species defined by its physical features.

Biological species concept

A species defined by its ability to interbreed and produce viable, fertile offspring.

Pre-zygotic mating barrier

A barrier that prevents mating or blocks fertilization.

Post-zygotic mating barrier

A barrier that occurs after the formation of a hybrid zygote, resulting in reduced viability or fertility.

Habitat isolation

Two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers.

Temporal isolation

Species that breed during different times of day, different seasons, or different years cannot interbreed.

Behavioral isolation

Courtship rituals and other behaviors unique to a species are effective barriers to mating.

Mechanical isolation

Morphological differences can prevent successful mating.

Gametic isolation

Eggs and sperm of different species are unable to fuse.

Hybrid inviability

The hybrid offspring is unable to survive.

Hybrid sterility

The hybrid offspring is infertile.

Hybrid breakdown

First-generation hybrids are fertile, but subsequent generations lose fertility.

Allopatric speciation

Speciation that occurs when gene flow is interrupted when a population is divided into geographically isolated subpopulations.

Sympatric speciation

Speciation that occurs in populations that live in the same geographic area.

Polyploidy

The presence of extra sets of chromosomes due to accidents during cell division.

Gradualism

A pattern of evolution in which new species evolve from their ancestors through a gradual change.

Punctuated equilibrium

A pattern of evolution in which long periods of little change are punctuated by abrupt episodes of speciation.

Adaptive radiation

The rapid evolution of many diversely adapted species from a common ancestor.

Mass extinction

The extinction of a large number of species within a relatively short period of geological time.