CH. 14 READING GUIDE: SPECIATION & EXTINCTION

Flashcards about Speciation & Extinction.

Macroevolution

Large-scale evolutionary change

Biological species concept

A population, or a group of populations, whose members interbreed and produce fertile offspring

Speciation

When some members of a population can no longer successfully interbreed with the rest of the group

Prezygotic reproductive barrier

Separation of species due to factors that prevent the formation of a zygote

Habitat isolation

Occupy different environments

Temporal isolation

Active or fertile at different times

Behavioral isolation

Different courtship activities

Mechanical isolation

Mating organs or pollinators incompatible

Gametic isolation

Gametes cannot unite or are incompatible

Postzygotic reproductive barrier

Separation of species due to selection against hybrid offspring

Hybrid inviability

Hybrid offspring fail to reach maturity

Hybrid infertility

Hybrid offspring are unable to reproduce

Hybrid breakdown

2nd-gen hybrid offspring have reduced fitness

Allopatric speciation

A new species forms when a geographical barrier physically separates a population into 2 groups that can't interbreed

Sympatric speciation

A new species arises while living in same physical area as its parent species

Gradualism

Evolution proceeds in small, incremental changes over many generations

Punctuated equilibrium

Relatively brief bursts of rapid speciation interrupts long periods of little change

Extinction

Death of all individuals of a species

Mass extinction

The disappearance of many species over relatively short expanses of time