Miller & Levine Biology - 17.1 Genes and Variation Flashcards

Vocabulary-style flashcards based on the Miller & Levine Biology transcript for Lesson 17.1 Genes and Variation.

Evolution (Genetic definition)

Any change in the relative frequency of alleles in the gene pool of a population over time.

Genotype

The particular combination of alleles that an organism carries.

Phenotype

All physical, physiological, and behavioral characteristics of an organism, produced by its genotype together with environmental conditions.

Natural Selection (Target)

The evolutionary process that acts directly on phenotype, not genotype.

Population Evolution

The concept that populations, rather than individual organisms, evolve over time through changes in allele frequencies.

Three Sources of Genetic Variation

Mutation, genetic recombination during sexual reproduction, and lateral gene transfer.

Mutation (Effect on Fitness)

Changes in phenotype that may be lethal, lower fitness, or be beneficial; they only matter in evolution if they can be passed to the next generation.

Germ line cells

The sex cells (eggs or sperm) where a mutation must occur in order to be passed from generation to generation.

Lateral Gene Transfer

The passing of genes from one individual to another that is not its offspring, occurring between organisms of the same or different species.

Single-gene trait

A trait where the number of phenotypes produced depends on being controlled by only one gene.

Polygenic trait

A trait controlled by how many genes control the trait, such as human height, typically resulting in a bell-shaped curve of variation.