Microevolution and Natural Selection

These flashcards cover key terms and concepts related to microevolution and natural selection, providing definitions and explanations to aid in understanding the material.

Genetic drift

Changes in allele frequencies due to chance events, affecting small populations significantly.

Hardy-Weinberg equilibrium

A principle stating that allele frequencies in a population remain constant from generation to generation in the absence of evolutionary influences.

Gene flow

The transfer of alleles or genes from one population to another, increasing genetic variation.

Natural selection

Mechanism by which individuals with favorable traits are more likely to survive and reproduce.

Directional selection

Selection that favors individuals at one extreme of a phenotypic range, causing a shift in the average phenotype.

Stabilizing selection

Selection that favors intermediate variants and acts against extreme phenotypes.

Disruptive selection

Selection that favors individuals at both extremes of a phenotypic range.

Phenotype

The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.

Allele frequency

Proportion of a particular allele among all allele copies in a population.

Microevolution

Small-scale evolutionary changes that occur within a species over time.

Mutation

A spontaneous change in the DNA sequence that can create new alleles.

Cystic fibrosis

An autosomal recessive genetic disorder caused by mutations in the CFTR gene, leading to respiratory and digestive issues.

Pedigree

A chart that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors.

Alleles

Different forms of a gene that can exist at a specific locus.

Punnett square

A grid used to predict the genotype and phenotype combinations in offspring from a genetic cross.

Sexual selection

A form of natural selection where individuals select mates based on observable traits.

Bottleneck effect

A sharp reduction in the size of a population due to environmental events or human activities, leading to reduced genetic diversity.

Founder effect

The loss of genetic variation that occurs when a new population is established by a very small number of individuals.

Homozygous

An individual having two identical alleles for a particular gene.

Heterozygous

An individual having two different alleles for a particular gene.