AP Biology Flashcards: Variations In Populations

What this deck covers

This deck focuses on Variations In Populations, giving you a quick way to review the definitions, rules, and examples that matter most for AP 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 a polymorphism?

Answer: The presence of two or more variants in a population. Maintained by balancing selection or neutral evolution.

Flashcard 2: What is the main effect of gene flow on populations?

Answer: It reduces genetic differences between populations. Homogenizes allele frequencies across connected populations.

Flashcard 3: Which term describes the movement of alleles between populations?

Answer: Gene flow. Migration introduces new alleles and reduces genetic differences.

Flashcard 4: Which concept describes the survival advantage of certain traits?

Answer: Adaptation. Traits that increase fitness become more common over time.

Flashcard 5: What role does mutation play in evolution?

Answer: It introduces new genetic variations. Without mutations, populations lack raw material for evolution.

Flashcard 6: Which type of selection favors intermediate phenotypes?

Answer: Stabilizing selection. Reduces variation by eliminating extreme phenotypes.

Flashcard 7: Identify a source of genetic variation.

Answer: Mutation. Creates new alleles through DNA sequence changes.

Flashcard 8: Which term refers to the genetic makeup of an organism?

Answer: Genotype. Determines which proteins are produced by an organism.

Flashcard 9: Which term refers to the genetic makeup of an organism?

Answer: Genotype. Determines which proteins are produced by an organism.

Flashcard 10: Identify a condition necessary for Hardy-Weinberg equilibrium.

Answer: No mutation. Also requires large population and random mating.

Flashcard 11: What does it mean for a population to be in Hardy-Weinberg equilibrium?

Answer: Allele frequencies do not change across generations. Indicates no net evolutionary change is occurring.

Flashcard 12: Identify an example of a non-random mating pattern.

Answer: Assortative mating. Individuals mate based on similar traits or characteristics.

Flashcard 13: What is an allele?

Answer: A variant form of a gene. Different versions arise through mutation and recombination.

Flashcard 14: Identify an example of a selective pressure.

Answer: Predators. Environmental factors that affect survival and reproduction.

Flashcard 15: Define the Hardy-Weinberg principle.

Answer: Allele and genotype frequencies remain constant in a population at equilibrium. Assumes no evolution is occurring in the population.

Flashcard 16: Define phenotype.

Answer: Observable characteristics of an organism. Results from interaction between genotype and environment.

Flashcard 17: What process increases genetic variation during meiosis?

Answer: Crossing over. Exchanges chromosome segments between homologs during prophase I.

Flashcard 18: What is a cline?

Answer: A gradual change in a trait across a geographic range. Results from adaptation to varying environmental conditions.

Flashcard 19: Define genetic hitchhiking.

Answer: An allele rises in frequency because it is linked to a beneficial allele. Occurs due to linkage disequilibrium between loci.

Flashcard 20: What role does genetic variation play in a population's adaptability?

Answer: It provides material for natural selection to act upon. Higher variation enables response to environmental challenges.

Flashcard 21: Identify one consequence of genetic drift.

Answer: Loss of genetic diversity. Random changes reduce total genetic variation over time.

Flashcard 22: Identify an example of a selective pressure.

Answer: Predators. Environmental factors that affect survival and reproduction.

Flashcard 23: What is the bottleneck effect?

Answer: Reduction in genetic diversity due to a dramatic population decrease. Survivors carry only a subset of original genetic diversity.

Flashcard 24: Define adaptive radiation.

Answer: The rapid evolution of diversely adapted species from a common ancestor. Often occurs when new habitats become available.

Flashcard 25: What is allele frequency?

Answer: Proportion of an allele in a population's gene pool. Changes over time through evolutionary forces.

Flashcard 26: Define adaptive radiation.

Answer: The rapid evolution of diversely adapted species from a common ancestor. Often occurs when new habitats become available.

Flashcard 27: Identify an example of a non-random mating pattern.

Answer: Assortative mating. Individuals mate based on similar traits or characteristics.

Flashcard 28: Which mechanism of evolution involves differential survival and reproduction?

Answer: Natural selection. Individuals with beneficial traits produce more offspring.

Flashcard 29: Identify a mechanism that can lead to speciation.

Answer: Reproductive isolation. Prevents gene flow between diverging populations.

Flashcard 30: What is a cline?

Answer: A gradual change in a trait across a geographic range. Results from adaptation to varying environmental conditions.

Flashcard 31: What is genetic recombination?

Answer: The exchange of genetic material between different organisms. Produces new allele combinations in offspring.

Flashcard 32: Identify an example of a prezygotic barrier.

Answer: Temporal isolation. Breeding occurs at different times, preventing mating.

Flashcard 33: What is directional selection?

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

Flashcard 34: Identify a condition necessary for Hardy-Weinberg equilibrium.

Answer: No mutation. Also requires large population and random mating.

Flashcard 35: What is a genetic locus?

Answer: The specific location of a gene on a chromosome. Each locus can have multiple allelic variants.

Flashcard 36: What does it mean for a population to be in Hardy-Weinberg equilibrium?

Answer: Allele frequencies do not change across generations. Indicates no net evolutionary change is occurring.

Flashcard 37: What is an allele?

Answer: A variant form of a gene. Different versions arise through mutation and recombination.

Flashcard 38: Identify a source of genetic variation.

Answer: Mutation. Creates new alleles through DNA sequence changes.

Flashcard 39: Which type of selection favors extreme phenotypes?

Answer: Disruptive selection. Eliminates intermediate phenotypes, increasing variation.

Flashcard 40: What process increases genetic variation during meiosis?

Answer: Crossing over. Exchanges chromosome segments between homologs during prophase I.

Flashcard 41: What is genetic variation?

Answer: Differences in DNA sequences among individuals in a population. This diversity enables adaptation to environmental changes.

Flashcard 42: What is the main effect of gene flow on populations?

Answer: It reduces genetic differences between populations. Homogenizes allele frequencies across connected populations.

Flashcard 43: Define genetic hitchhiking.

Answer: An allele rises in frequency because it is linked to a beneficial allele. Occurs due to linkage disequilibrium between loci.

Flashcard 44: What is meant by 'fitness' in an evolutionary context?

Answer: Ability to survive and reproduce in a given environment. Measured by relative reproductive success compared to others.

Flashcard 45: Define punctuated equilibrium.

Answer: Rapid evolutionary change followed by periods of stability. Explains patterns seen in fossil records.

Flashcard 46: Define genetic drift.

Answer: Random changes in allele frequencies in a population. Stronger in small populations due to sampling effects.

Flashcard 47: Identify a factor that can cause allele frequencies to change.

Answer: Natural selection. Drift, gene flow, and mutation also cause changes.

Flashcard 48: What is a genetic locus?

Answer: The specific location of a gene on a chromosome. Each locus can have multiple allelic variants.

Flashcard 49: What is a postzygotic barrier?

Answer: A mechanism that reduces the viability or reproductive capacity of hybrids. Acts after fertilization to reduce hybrid success.

Flashcard 50: Which term describes the movement of alleles between populations?

Answer: Gene flow. Migration introduces new alleles and reduces genetic differences.

Flashcard 51: Identify a factor that can lead to genetic drift.

Answer: Small population size. Fewer individuals mean greater random sampling effects.

Flashcard 52: Define phenotype.

Answer: Observable characteristics of an organism. Results from interaction between genotype and environment.

Flashcard 53: What is genetic variation?

Answer: Differences in DNA sequences among individuals in a population. This diversity enables adaptation to environmental changes.

Flashcard 54: What is a postzygotic barrier?

Answer: A mechanism that reduces the viability or reproductive capacity of hybrids. Acts after fertilization to reduce hybrid success.

Flashcard 55: Identify an example of a prezygotic barrier.

Answer: Temporal isolation. Breeding occurs at different times, preventing mating.

Flashcard 56: What is allele frequency?

Answer: Proportion of an allele in a population's gene pool. Changes over time through evolutionary forces.

Flashcard 57: Which mechanism of evolution involves differential survival and reproduction?

Answer: Natural selection. Individuals with beneficial traits produce more offspring.

Flashcard 58: Identify one consequence of genetic drift.

Answer: Loss of genetic diversity. Random changes reduce total genetic variation over time.

Flashcard 59: What role does mutation play in evolution?

Answer: It introduces new genetic variations. Without mutations, populations lack raw material for evolution.

Flashcard 60: What is the founder effect?

Answer: Loss of genetic variation when a new population is established. Colonizers represent limited genetic sample of source population.

Flashcard 61: Identify a factor that can lead to genetic drift.

Answer: Small population size. Fewer individuals mean greater random sampling effects.

Flashcard 62: Define punctuated equilibrium.

Answer: Rapid evolutionary change followed by periods of stability. Explains patterns seen in fossil records.

Flashcard 63: Which type of natural selection can lead to speciation?

Answer: Disruptive selection. Creates reproductively isolated subpopulations.

Flashcard 64: What is genetic recombination?

Answer: The exchange of genetic material between different organisms. Produces new allele combinations in offspring.

Flashcard 65: Identify a mechanism that can lead to speciation.

Answer: Reproductive isolation. Prevents gene flow between diverging populations.

Flashcard 66: Which type of natural selection can lead to speciation?

Answer: Disruptive selection. Creates reproductively isolated subpopulations.

Flashcard 67: Which type of selection favors intermediate phenotypes?

Answer: Stabilizing selection. Reduces variation by eliminating extreme phenotypes.

Flashcard 68: Identify a factor that can cause allele frequencies to change.

Answer: Natural selection. Drift, gene flow, and mutation also cause changes.

Flashcard 69: What role does genetic variation play in a population's adaptability?

Answer: It provides material for natural selection to act upon. Higher variation enables response to environmental challenges.

Flashcard 70: What is a genetic bottleneck?

Answer: A sharp reduction in the size of a population. Results in loss of rare alleles through random sampling.

Flashcard 71: What is meant by 'fitness' in an evolutionary context?

Answer: Ability to survive and reproduce in a given environment. Measured by relative reproductive success compared to others.

Flashcard 72: What is directional selection?

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

Flashcard 73: Define the Hardy-Weinberg principle.

Answer: Allele and genotype frequencies remain constant in a population at equilibrium. Assumes no evolution is occurring in the population.

Flashcard 74: Which concept describes the survival advantage of certain traits?

Answer: Adaptation. Traits that increase fitness become more common over time.

Flashcard 75: Define genetic drift.

Answer: Random changes in allele frequencies in a population. Stronger in small populations due to sampling effects.