Practice Questions

The Modern Synthesis integrated Darwinian natural selection with Mendelian genetics, mathematical population genetics, and chromosome theory to explain evolution at the molecular and population levels.

Evolution is the broader phenomenon (descent with modification), whereas natural selection is one of the primary mechanisms (alongside drift, gene flow, mutation) that drive it.

The selective pressure (predation) favors one extreme of the phenotypic spectrum (dark fur), causing a directional shift in the population's average fur color over time.

Disruptive selection splits the population's phenotypic profile into two distinct groups by selecting against the average/intermediate phenotype.

Speciation occurs gradually as populations diverge genetically and phenotypically in response to different selective pressures, eventually leading to reproductive isolation.

The HMS Beagle voyage (1831–1836) exposed Darwin to diverse ecosystems and fossil beds, particularly in South America and the Galapagos, which inspired his thinking on evolution.

Evolutionary fitness is defined solely by reproductive success; it is a measure of how many copies of its genes an individual passes on to subsequent, reproducing generations.

Mutation and variation generation are random events, but natural selection is a non-random sorting process that systematically favors traits that confer a reproductive advantage.

As a population grows toward its carrying capacity, resources (food, shelter, water) become limiting, which intensifies competition and the struggle for survival.

Meiotic processes (independent assortment, crossing over, and random fertilization) shuffle alleles to create unique genetic combinations, producing the heritable variation key to selection.