Biology 13th Edition Raven Unit 12: Genes Within Populations Quiz

Genetic Variation and Evolution

• The main source of genetic variation in natural populations is mutation.
• The concept of species accumulating differences through time, leading to the emergence of new species, is associated with gradualism.

Darwin's Proposal

• Darwin's proposal is distinct from those of his predecessors in terms of evolutionary mechanisms because it emphasizes the role of natural selection as the primary driver of evolutionary change.

Natural Selection and Evolutionary Change

• Natural selection leads to evolutionary change in allele frequencies by favoring individuals with advantageous traits, resulting in an increase in their representation in the population over time.

Introduction of New Alleles

• The primary process through which new alleles are introduced into a population is mutation.

Hardy–Weinberg Principle

• The Hardy–Weinberg principle predicts genotype frequencies and can be written as an equation: p2 + 2pq + q2 = 1.
• This equation represents the frequencies of the three possible genotypes (AA, Aa, and aa) in a population.

Hardy–Weinberg Equilibrium

• One of the assumptions for Hardy–Weinberg equilibrium is that the population is not evolving, meaning that there is no mutation, genetic drift, gene flow, or natural selection.
• The assumption that is NOT one of the assumptions for Hardy–Weinberg equilibrium is that the population is evolving.

Variation in Natural Populations

• The type of variation within natural populations that was a puzzle to Darwin and his contemporaries was continuous variation, as it did not fit with the prevailing view of species as fixed and unchanging.

Hardy–Weinberg Equation

• The Hardy–Weinberg equation p2 + 2pq + q2 = 1 represents the frequencies of the three possible genotypes (AA, Aa, and aa) in a population.

Inheritance in the 1800s

• During the mid-1800s, scientists widely accepted the idea that inheritance is due to the blending of parental traits, rather than the transmission of discrete particles (now known as genes).