MCQs

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.

Stabilizing selection favors the intermediate phenotype (medium-sized wings) and selects against both extreme phenotypes (very short and very long wings).

Special Creation is a non-evolutionary concept proposing that species are fixed, unchanging entities created in their current forms, whereas Darwinism emphasizes descent with modification.

The selective pressure (predation) favors the faster extreme of swimming speeds, causing a directional shift in the average speed of the prey population over time.

Darwin's 1859 book went beyond speculating about evolution; it presented a vast array of evidence and proposed natural selection as the functional mechanism of evolutionary change.

Without pre-existing genetic variation, natural selection has no raw material to work with. If the environmental change is lethal to all identical individuals, the population will go extinct.

Because both extreme phenotypes (white and dark brown) are favored in their respective micro-habitats, while intermediate colors are less fit in both, disruptive selection is at play.

Wallace independently co-discovered the theory of natural selection, prompting Darwin to quickly publish his own extensive findings in "On the Origin of Species" in 1859.

Differential reproductive success is the core of natural selection; it means that individuals with traits better suited to the environment leave more offspring behind than less-suited individuals.

Artificial selection demonstrates the power of selective breeding to dramatically modify organisms, suggesting that a similar process (natural selection) operates in nature over longer periods.

Directional selection shifts the phenotypic distribution toward one extreme (larger beaks), typically in response to a directional change in environmental conditions.

Neo-Darwinism combines Darwinian selection with Mendelian genetics, defining evolution as a change in allele frequencies within a population's gene pool over generations.

Selective pressure (e.g., predators, climate, disease) is the environmental force that drives natural selection by favoring certain phenotypes over others.

The rapid development of resistance in bacteria and pests is a documented, direct observation of natural selection occurring in contemporary times under strong selective pressures.

The drought alters the environment, making the brown phenotype more advantageous. Brown insects will survive predation better, reproduce more, and increase the frequency of the brown allele.

Darwin argued that complex structures evolve via the gradual accumulation of many slight, heritable modifications, with each step improving the organism's fitness compared to the previous state.

Individuals do not adapt by mutating their own genomes in response to environmental demands. Mutations are random; natural selection simply filters pre-existing genetic variations.