Biology Flashcards: Relate Variation To Selection Pressure

What this deck covers

This deck focuses on Relate Variation To Selection Pressure, giving you a quick way to review the definitions, rules, and examples that matter most for Biology.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is meant by differential reproductive success?

Answer: Some individuals leave more offspring than others. Fitness differences drive changes in allele frequencies.

Flashcard 2: 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 3: Identify the selection pressure most directly increased by a new predator in the habitat.

Answer: Predation pressure. New predators create immediate survival challenges.

Flashcard 4: What is the difference between genotype and phenotype?

Answer: Genotype is genetic makeup; phenotype is expressed traits. Selection acts on phenotype but changes genotype frequencies.

Flashcard 5: Identify the most likely result if a drought reduces water availability for many years.

Answer: Selection favors traits that improve water conservation. Drought creates strong selection for water-saving adaptations.

Flashcard 6: Identify the selection pressure most directly increased by a new predator in the habitat.

Answer: Predation pressure. New predators create immediate survival challenges.

Flashcard 7: 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 8: Which type of selection is occurring if the population mean shifts toward larger size?

Answer: Directional selection. Population mean shifts toward the favored direction.

Flashcard 9: 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.

Flashcard 10: What is artificial selection?

Answer: Human-directed breeding that changes trait frequencies. Humans act as the selective agent in breeding programs.

Flashcard 11: 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 12: 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 13: What is directional selection?

Answer: Selection that favors one extreme phenotype. The population mean shifts toward the favored extreme.

Flashcard 14: 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 15: Which statement best describes selection when the environment changes rapidly?

Answer: Previously beneficial traits may become neutral or harmful. Environmental change can reverse previous selective advantages.

Flashcard 16: What is the difference between genotype and phenotype?

Answer: Genotype is genetic makeup; phenotype is expressed traits. Selection acts on phenotype but changes genotype frequencies.

Flashcard 17: What is the selective advantage of camouflage in many habitats?

Answer: Reduced detection by predators or prey. Camouflage increases survival by avoiding detection.

Flashcard 18: 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 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: 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 21: 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 22: 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 23: What is gene pool in population genetics?

Answer: All alleles present in a population. The total genetic diversity available for selection.

Flashcard 24: 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 25: Identify the correct statement about mutations and selection.

Answer: Mutations arise randomly; selection is nonrandom. Mutation provides variation; selection filters it non-randomly.

Flashcard 26: What is an example of a biotic selection pressure?

Answer: Predation (an interaction with other organisms). Biological interactions create complex selection pressures.

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: Which type of selection is occurring if extremes are removed and variation decreases?

Answer: Stabilizing selection. Intermediate phenotypes are favored over extremes.

Flashcard 29: 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 30: 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 31: What is adaptation?

Answer: A heritable trait that increases fitness in a given environment. Adaptations evolve through natural selection over time.

Flashcard 32: 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 33: What is pesticide resistance an example of?

Answer: Natural selection favoring resistant pests. Pesticides act as environmental selection pressures.

Flashcard 34: Which trait is most likely favored when food becomes scarce and hard to access?

Answer: Traits that improve foraging efficiency or resource use. Food scarcity selects for improved resource acquisition.

Flashcard 35: Which trait is most likely favored when food becomes scarce and hard to access?

Answer: Traits that improve foraging efficiency or resource use. Food scarcity selects for improved resource acquisition.

Flashcard 36: What is the role of recombination in variation?

Answer: It reshuffles alleles, creating new genotype combinations. Sexual reproduction increases genetic diversity in offspring.

Flashcard 37: What does it mean that selection acts on phenotypes?

Answer: Environment filters expressed traits, not alleles directly. Selection cannot directly see genes, only their expression.

Flashcard 38: 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 39: 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 40: Which type of selection is occurring if the population mean shifts toward larger size?

Answer: Directional selection. Population mean shifts toward the favored direction.

Flashcard 41: 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 42: What is the selective advantage of camouflage in many habitats?

Answer: Reduced detection by predators or prey. Camouflage increases survival by avoiding detection.

Flashcard 43: 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 44: 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 45: Which type of selection is occurring if intermediates are selected against and extremes increase?

Answer: Disruptive selection. Both extremes are favored over intermediate forms.

Flashcard 46: What does it mean that evolution is measured in populations?

Answer: Allele frequencies change across generations in a population. Individuals don't evolve; population gene pools change.

Flashcard 47: What is an example of an abiotic selection pressure?

Answer: Temperature (a nonliving environmental factor). Physical environment creates selection without other organisms.

Flashcard 48: Identify the outcome of strong selection against a harmful phenotype.

Answer: That phenotype becomes less common over generations. Strong selection reduces frequency of disadvantageous traits.

Flashcard 49: What does it mean that selection acts on phenotypes?

Answer: Environment filters expressed traits, not alleles directly. Selection cannot directly see genes, only their expression.

Flashcard 50: 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 51: 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 52: 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 53: What is disruptive selection?

Answer: Selection that favors both extreme phenotypes over intermediates. Can lead to population splitting into two distinct forms.

Flashcard 54: 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 55: 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 56: Which type of selection is occurring if intermediates are selected against and extremes increase?

Answer: Disruptive selection. Both extremes are favored over intermediate forms.

Flashcard 57: Which option best defines "selective agent"?

Answer: The specific factor (for example, predator) causing selection. The specific environmental force driving selection.

Flashcard 58: What is fitness in evolutionary biology?

Answer: Relative reproductive success of an individual or genotype. Higher fitness means more offspring in the next generation.

Flashcard 59: What is pesticide resistance an example of?

Answer: Natural selection favoring resistant pests. Pesticides act as environmental selection pressures.

Flashcard 60: What is adaptation?

Answer: A heritable trait that increases fitness in a given environment. Adaptations evolve through natural selection over time.

Flashcard 61: Which type of selection is occurring if extremes are removed and variation decreases?

Answer: Stabilizing selection. Intermediate phenotypes are favored over extremes.

Flashcard 62: 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 63: What is the role of recombination in variation?

Answer: It reshuffles alleles, creating new genotype combinations. Sexual reproduction increases genetic diversity in offspring.

Flashcard 64: 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 65: Identify the most likely result if a drought reduces water availability for many years.

Answer: Selection favors traits that improve water conservation. Drought creates strong selection for water-saving adaptations.

Flashcard 66: What is meant by differential reproductive success?

Answer: Some individuals leave more offspring than others. Fitness differences drive changes in allele frequencies.

Flashcard 67: What does it mean that evolution is measured in populations?

Answer: Allele frequencies change across generations in a population. Individuals don't evolve; population gene pools change.

Flashcard 68: 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 69: What is gene pool in population genetics?

Answer: All alleles present in a population. The total genetic diversity available for selection.

Flashcard 70: 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.

Flashcard 71: What is stabilizing selection?

Answer: Selection that favors intermediate phenotypes. Reduces variation by eliminating extreme phenotypes.

Flashcard 72: 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 73: Which option best defines "selective agent"?

Answer: The specific factor (for example, predator) causing selection. The specific environmental force driving selection.

Flashcard 74: Identify the outcome of strong selection against a harmful phenotype.

Answer: That phenotype becomes less common over generations. Strong selection reduces frequency of disadvantageous traits.

Flashcard 75: What is antibiotic resistance an example of?

Answer: Natural selection favoring resistant bacterial variants. Antibiotics create strong directional selection pressure.

Flashcard 76: What is natural selection?

Answer: Differential survival and reproduction of heritable variants. This process drives evolutionary change in populations.

Flashcard 77: Identify the correct conclusion if a trait increases survival but reduces mating success.

Answer: Overall fitness may decrease if reproduction drops enough. Fitness depends on both survival and reproductive components.

Flashcard 78: 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 79: What is heritability in the context of selection?

Answer: The degree to which trait differences are genetic and inherited. Only heritable traits can respond to natural selection.

Flashcard 80: Identify the correct conclusion if a trait increases survival but reduces mating success.

Answer: Overall fitness may decrease if reproduction drops enough. Fitness depends on both survival and reproductive components.

Flashcard 81: 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 82: Identify the correct statement about mutations and selection.

Answer: Mutations arise randomly; selection is nonrandom. Mutation provides variation; selection filters it non-randomly.

Flashcard 83: 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 84: Which statement best describes selection when the environment changes rapidly?

Answer: Previously beneficial traits may become neutral or harmful. Environmental change can reverse previous selective advantages.

Flashcard 85: 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 86: What is antibiotic resistance an example of?

Answer: Natural selection favoring resistant bacterial variants. Antibiotics create strong directional selection pressure.