The evolution of populations

temporal isolation

separate populations with factors such as time, such as when one population reproduces in the spring and other reproduces in the summer

normal distribution

looks like a bell shaped curve, having the highest frequency in the middle;

geographic isolation

separates populations with physical barriers so that members of each population no longer have contact with each other

Hardy-Weinberg Equilibrium

Occurs when there are no changes in allele frequencies for a certain trait from generation to generation; rarely occurs in real populations.

punctuated equilibrium

A pattern of evolution that is seen in the fossil record; consist of short periods with lots of evolutionary activity, followed by long periods with much less evolutionary activity

Speciation

Refers to the evolutionary process by which new biological species arise.

behavioral isolation

separates populations with different courtship or mating rituals

Gradualism

Suggests that organisms evolve through a process of slow and constant change.

stabilizing selection

occurs when natural selection selects for individuals with the intermediate phenotype

normal distribution

occurs when natural selection is not acting on a population for a certain trait

directional selection

occurs when natural selection selects for individuals with one extreme phenotype

Disruptive Selection

Occurs when natural selection selects for individuals with both extreme phenotypes

geographic isolation (species from)

species from two populations are separated by physical barriers

reproductive isolation (species from)

species from two populations can no longer mate successfully, for any reason

behavioral isolation (species from)

species from two populations are separated due to differences in courtship or sting rituals

temporal isolation (species from)

species from two populations are separated due to differences in the timing of their reproduction

coevolution

process in which two species evolve in response to changes in each other, over many generations

convergent evolution

process in which unrelated species evolve similar traits while adapting to similar environments

divergent evolution

process in which closely related species become more and more different as they adapt to different environments

microevolution

process which can occur over a few generations, in which a populations allele frequencies change in any way

Differentiation

Process where isolated populations become so different that they cannot interbreed anymore

Adaptive Radiation (shortened)

A rapid increase in the number of species with a common ancestor

Gene Pool (shortened)

All the alleles in a population

Directional selection (shortened)

favors one extreme phenotype

Stabilizing selection (shortened)

favors the intermediate phenotype

Disruptive selection (shortened)

Favors both extreme phenotypes

Speciation (shortened)

Many species evolving from one

punctuated equilibrium (analogy)

long, flat surfaces interrupted by short, steep steps

genetic drift (analogy)

including only two people in a survey of a large community, and not getting representative results

normal distribution (analogy)

median clothing sizes being the most common in department stores

Extinction (analogy)

A radio station that goes off the air

gene flow (analogy)

many colleges sharing and exchanging research ideas with each other

Allele Frequency (analogy)

How often a certain letter-number combination is called during bingo

gene pool (analogy)

a phone book that contains all of the phone numbers of everyone in a city

geographic isolation (analogy)

sound-proof that prevents people from hearing each other