Lecture Notes on Natural Selection and Speciation

Flashcards about Natural Selection and Speciation

The different types of Selection are:

Stabilizing, Directional, Disruptive, Sexual, Artificial

Natural Selection is a __

Process where organisms better adapted to their environment survive and produce more offspring

Natural Selection is caused by __

Random Genetic Mutations

In stabilizing selection:

Selective pressures select against the two extremes of a trait

In directional selection:

One extreme of the trait distribution experiences selection against it

In disruptive selection:

Selection pressures act against individuals in the middle of the trait; extremes are best

In sexual selection:

The female of a species tends to choose mates based on traits they find attractive

In artificial selection:

Humans do the selecting of traits

Speciation is:

The formation of a new species; occurs when members of the same species become isolated and can no longer reproduce

A species is:

A population whose members can breed and produce fertile offspring

Prezygotic barriers are:

Anything that prevents fertilization

Postzygotic barriers:

Reduce the viability or the reproductive capacity of the hybrid offspring

Sympatric speciation involves:

No physical barriers

Allopatric speciation involves:

Physical barriers separate the species

A temporal barrier involves:

Different mating seasons prevent organisms living in the same area from mating with each other

A behavior barrier involves:

Species have specific behaviors for identification; mating rituals are a major part of species recognition and fitness

A geographic barrier:

A single location can have various habitats for species OR they can be separated by a larger geographic barrier like a river

Other reproductive barriers are:

Reproductive structures are incompatible

Pioneer species are:

The first species to arrive to a new location

Convergent Evolution is:

When species with different ancestral origins have developed similar features due to nature favoring similar traits

Divergent Evolution is:

Two different species share the same ancestral origins but have evolved differently

Coevolution is:

Two (or more) species reciprocally affect each other's evolution