Evolutionary Biology: Microevolution and Mutations

15 vocabulary flashcards covering key concepts from Dr. Heather Williams' Lecture 7 on Microevolution and Mutations.

Population

A group of individuals from a single species.

Allele frequency

The number of times an allele occurs in the population, typically represented as a proportion of the whole.

Microevolutionary forces

The mechanisms that cause allele frequencies to change: gene flow, non-random mating, genetic drift, mutation, and selection.

Gene flow

The movement of alleles from one population to another of the same species.

Assortative mating

A type of non-random mating where organisms of similar phenotype mate more often than expected by random chance.

Genetic drift

Changes in allele frequencies due to random chance events, particularly significant in small population sizes.

Founder effect

A type of genetic drift where a new population is started by a small number of individuals who move to an area with no pre-existing population of the same species.

Bottleneck effect

A type of genetic drift that occurs when a population undergoes a drastic reduction in size, leading to changes in allele frequencies in the surviving population.

Mutation

The ultimate source of all genetic variability, involving alterations in the DNA sequence.

Codons

Sequences of three nucleotides in mRNA that specify particular amino acids or act as stop signals during protein synthesis.

Degenerate code

A characteristic of the genetic code where more than one codon can code for the same amino acid.

Reading frame

The way in which a sequence of nucleotides is grouped into triplets (codons) during translation; critical for synthesizing the correct protein.

Frameshift mutation

A mutation caused by the insertion or deletion of nucleotides not in multiples of three, which alters the reading frame and changes all downstream codons.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during meiosis, leading to an abnormal number of chromosomes in daughter cells.

Aneuploidy

A condition in which an individual has gained or lost one or more chromosomes, resulting in an abnormal chromosome number.