(3) Unit 7 Topics 4 5 and 12 Part 1 Packet 1

Population

A group of individuals of the same species that live in the same area and interbreed to produce fertile offspring.

Gene pool

A population's genetic makeup, consisting of all the copies of every type of allele within that population.

Fixed allele

An allele that is the only one present for a particular locus in a population, due to a loss of other alleles.

Genetic diversity

The variety of different genetic makeups within a population, which is crucial for survival and adaptability.

Microevolution

Small-scale genetic changes in a population over time, often tracked through changes in allele frequencies.

Mutations

Changes to the DNA that can alter genetic makeup, resulting in new alleles and genetic variation.

Genetic drift

A chance event that causes changes in allele frequency from one generation to the next, most significant in small populations.

Bottleneck effect

When a large population is drastically reduced by a non-selective disaster, leading to changes in allele frequencies.

Founder effect

When a few individuals from a large population become isolated and establish a new population with a different gene pool.

Gene flow

The transfer of alleles into or out of a population due to the movement of fertile individuals or gametes.

Natural selection

The process whereby individuals with favorable traits are more likely to survive and reproduce, leading to changes in population.

Relative fitness

The number of surviving offspring an individual produces compared to others in the population, measuring reproductive success.

Directional selection

A mode of natural selection that favors one extreme phenotype over the average or the other extreme.

Stabilizing selection

A mode of natural selection that favors average phenotypes and selects against extreme phenotypes.

Disruptive selection

A mode of natural selection that favors extreme phenotypes at both ends of the spectrum and selects against average phenotypes.

Sexual selection

A type of natural selection where individuals with certain traits are preferred as mates, often resulting in showy or unique characteristics.