All flashcards
Flashcard 1: Which scenario best illustrates sexual selection rather than natural selection for survival?
Answer: A trait increases mating success despite survival costs. Sexual selection can oppose survival-based natural selection.
Flashcard 2: Which statement best predicts allele frequency change if a phenotype has higher fitness?
Answer: Alleles contributing to that phenotype tend to increase over generations. Higher fitness genotypes become more common over time.
Flashcard 3: Which option best explains why selection cannot produce a needed trait on demand?
Answer: Selection acts only on existing heritable variation. Selection cannot create variation; it only filters what exists.
Flashcard 4: Identify the correct interpretation if a new disease increases mortality in one genotype.
Answer: The disease is a selection pressure against that genotype. Disease creates differential survival based on genotype.
Flashcard 5: Which outcome best indicates an adaptation rather than an acclimation?
Answer: A heritable trait becomes more common across generations. Adaptation involves genetic change across generations.
Flashcard 6: What is the main requirement for natural selection to occur?
Answer: Heritable variation that affects fitness. Without heritable variation affecting fitness, no evolution occurs.
Flashcard 7: What is the role of recombination in variation?
Answer: It reshuffles alleles, creating new genotype combinations. Sexual reproduction increases genetic diversity in offspring.
Flashcard 8: What is the role of mutations in natural selection?
Answer: They create new alleles that can be acted on by selection. Without mutations, there would be no variation to select from.
Flashcard 9: What is adaptation?
Answer: A heritable trait that increases fitness in a given environment. Adaptations evolve through natural selection over time.
Flashcard 10: What is a selection pressure in natural selection?
Answer: An environmental factor that affects survival or reproduction. These pressures determine which traits are advantageous.
Flashcard 11: What is genetic variation in a population?
Answer: Heritable differences in DNA/alleles among individuals. This forms the raw material for natural selection to act upon.
Flashcard 12: Which scenario best illustrates sexual selection rather than natural selection for survival?
Answer: A trait increases mating success despite survival costs. Sexual selection can oppose survival-based natural selection.
Flashcard 13: Identify the most likely effect of a selective pressure that targets juveniles only.
Answer: Traits improving juvenile survival increase in frequency. Early survival strongly impacts lifetime reproductive success.
Flashcard 14: Which statement best predicts allele frequency change if a phenotype has higher fitness?
Answer: Alleles contributing to that phenotype tend to increase over generations. Higher fitness genotypes become more common over time.
Flashcard 15: Identify the best conclusion if two phenotypes have equal fitness in an environment.
Answer: Selection does not favor either phenotype (no directional change). Equal fitness means no selective advantage for either form.
Flashcard 16: Which outcome best indicates that a trait is heritable rather than purely environmental?
Answer: Offspring resemble parents for the trait across environments. Heritability shows genetic rather than environmental control.
Flashcard 17: What is antibiotic resistance an example of?
Answer: Natural selection favoring resistant bacterial variants. Antibiotics create strong directional selection pressure.
Flashcard 18: Identify the correct statement about mutations and selection.
Answer: Mutations arise randomly; selection is nonrandom. Mutation provides variation; selection filters it non-randomly.
Flashcard 19: What is meant by "selection is environment-dependent"?
Answer: A trait can be beneficial in one environment and harmful in another. Fitness depends entirely on environmental context.
Flashcard 20: What is the selective advantage of camouflage in many habitats?
Answer: Reduced detection by predators or prey. Camouflage increases survival by avoiding detection.
Flashcard 21: What is an example of a biotic selection pressure?
Answer: Predation (an interaction with other organisms). Biological interactions create complex selection pressures.
Flashcard 22: What is an example of an abiotic selection pressure?
Answer: Temperature (a nonliving environmental factor). Physical environment creates selection without other organisms.
Flashcard 23: What is meant by differential reproductive success?
Answer: Some individuals leave more offspring than others. Fitness differences drive changes in allele frequencies.
Flashcard 24: Which statement best distinguishes natural selection from evolution?
Answer: Selection is a mechanism; evolution is allele frequency change. Selection is the cause; evolution is the measured outcome.
Flashcard 25: What is meant by "trade-off" in adaptations?
Answer: A trait increases fitness in one way but decreases it in another. Evolution often involves compromises between competing needs.
Flashcard 26: Which option best defines "selective agent"?
Answer: The specific factor (for example, predator) causing selection. The specific environmental force driving selection.
Flashcard 27: What is the correct relationship between selection and variation?
Answer: Selection filters existing heritable variation; it does not create it. Selection sorts existing variation; it doesn't generate novelty.
Flashcard 28: Identify the most likely selective force when bacteria are exposed to an antibiotic.
Answer: Antibiotic acts as a selection pressure favoring resistant cells. Antibiotics create directional selection for resistance.
Flashcard 29: Which condition must be true for selection to change allele frequencies?
Answer: Trait variation must be heritable and affect fitness. Both conditions are necessary for evolutionary change.
Flashcard 30: Identify the correct inference if only the fastest prey survive predator attacks.
Answer: Selection favors alleles that increase speed. Speed becomes directly linked to survival and reproduction.