What is evolution in the context of population genetics?	A change in allele frequencies in a population over successive generations.
What is differential reproductive success?	The phenomenon where individuals with traits better suited to the environment survive and produce more viable offspring.
How is evolutionary fitness measured?	By an organism's relative contribution to the gene pool of the next generation.
_____ acts directly on an individual's phenotype, but it is populations that evolve over time.	Natural selection
Natural selection acts directly on an individual's phenotype, but it is _____ that evolve over time.	populations
What is an adaptation in evolutionary biology?	A heritable trait that enhances an organism's ability to survive and reproduce in a specific environment.
What is directional selection?	Natural selection that favors individuals at one extreme phenotypic range over others.
What is stabilizing selection?	Natural selection that favors intermediate variants by acting against extreme phenotypes.
What is disruptive selection?	Natural selection that favors individuals at both phenotypic extremes over intermediate phenotypes.
What is artificial selection?	The selective breeding of domesticated plants and animals by humans to encourage desirable phenotypic traits.
What is genetic drift?	A change in the allele frequencies of a population due to chance events.
In what size population does genetic drift have the strongest effect?	Small populations.
What is the bottleneck effect?	A sharp reduction in population size caused by an environmental disaster, randomly altering allele frequencies.
What is the founder effect?	Genetic drift that occurs when a few individuals become isolated from a larger population and establish a new colony.
What is gene flow?	The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes.
In the Hardy–Weinberg equation p + q = 1, what does p represent?	The frequency of the dominant allele.
In the Hardy–Weinberg equation p + q = 1, what does q represent?	The frequency of the recessive allele.
In the Hardy–Weinberg equation p² + 2pq + q² = 1, which term represents the frequency of heterozygous individuals?	2pq
In the Hardy–Weinberg equation p² + 2pq + q² = 1, which term represents the frequency of homozygous dominant individuals?	p²
In the Hardy–Weinberg equation p² + 2pq + q² = 1, which term represents the frequency of homozygous recessive individuals?	q²
Name the five conditions required for a population to maintain Hardy–Weinberg equilibrium.	No mutations, random mating, no natural selection, extremely large population size, and no gene flow.
If allele frequencies in a population change from one generation to the next, the population is violating _____ and undergoing evolution.	Hardy–Weinberg equilibrium
If allele frequencies in a population change from one generation to the next, the population is violating Hardy–Weinberg equilibrium and undergoing _____.	evolution
What are homologous structures?	Anatomical features that share a common evolutionary origin despite differences in current function.
What are analogous structures?	Features that perform similar functions but evolved independently due to convergent evolution, not shared ancestry.
What is convergent evolution?	The independent evolution of similar features in distinct evolutionary lineages due to similar selective pressures.
What is a vestigial structure?	A remnant feature that served an important function in an organism's ancestors but has reduced or no function today.
What provides the most direct and accurate molecular evidence for determining evolutionary relationships among species?	Comparisons of DNA nucleotide sequences or amino acid sequences.
What is a phylogenetic tree?	A diagram that represents a hypothesis about the evolutionary history and relationships of a group of organisms.
On a phylogenetic tree, what does a branch point (node) represent?	The most recent common ancestor of the evolutionary lineages that diverge from that point.
In cladistics, an _____ is a species or group of species that diverged before the lineage containing the group of interest (the ingroup).	outgroup
In cladistics, an outgroup is a species or group of species that diverged before the lineage containing the group of interest (the _____).	ingroup
What is a sister taxon?	A group of organisms that share an immediate common ancestor not shared by any other group.
What is a monophyletic group (clade)?	A group composed of an ancestral species and all of its descendants.
What is a shared derived character?	An evolutionary novelty that is unique to a particular clade and not found in its ancestors.
What does the principle of maximum parsimony state when constructing a phylogenetic tree?	The tree that requires the fewest evolutionary changes (fewest mutations or character transitions) is the most likely.
According to the biological species concept, what defines a species?	A group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.
What is allopatric speciation?	Speciation that occurs when populations are geographically separated from one another.
What is sympatric speciation?	Speciation that occurs in populations that live in the same geographic area.
What is a prezygotic reproductive barrier?	An isolating mechanism that prevents mating or fertilization between different species.
What is temporal isolation?	A prezygotic barrier in which species breed during different seasons, times of day, or years.
What is behavioral isolation?	A prezygotic barrier in which specific courtship rituals or behaviors prevent interbreeding.
What is mechanical isolation?	A prezygotic barrier where morphological differences prevent successful copulation.
What is gametic isolation?	A prezygotic barrier where sperm of one species cannot fertilize the eggs of another species.
What is a postzygotic reproductive barrier?	A mechanism that prevents hybrid zygotes from developing into viable, fertile adults.
What is hybrid sterility?	A postzygotic barrier where the hybrid offspring develops into a viable adult but cannot produce functional gametes.
What is punctuated equilibrium?	A model of evolution where species undergo long periods of apparent stasis interrupted by sudden bursts of rapid change.
What is gradualism in the context of evolutionary tempo?	A model where species diverge slowly and steadily through small morphological changes over long periods.
_____ is the rapid evolution of many diversely adapted species from a common ancestor upon introduction to novel environmental niches.	Adaptive radiation