All flashcards
Flashcard 1: Which condition is violated if every individual has the same phenotype for a trait?
Answer: Variation. No differences means selection has nothing to act upon.
Flashcard 2: Limited application: If a population experiences a sudden drought, what changes first: individuals or allele frequencies?
Answer: Individuals are filtered first; allele frequencies change across generations. Selection acts immediately; evolution requires generational change.
Flashcard 3: What does the term "fitness" mean in evolutionary biology?
Answer: Relative reproductive success in a given environment. Not physical strength, but reproductive output compared to others.
Flashcard 4: What is artificial selection?
Answer: Human-directed breeding that increases desired traits. Demonstrates selection principles through deliberate breeding choices.
Flashcard 5: What is meant by "natural selection is not goal-directed"?
Answer: It has no foresight; it favors traits beneficial in current conditions. Selection responds to current conditions, not future needs.
Flashcard 6: What is the correct sequence of events in natural selection?
Answer: Variation → heritability → competition → differential reproduction → allele change. Standard order from initial variation to evolutionary change.
Flashcard 7: Which condition is violated if a trait difference is purely environmental and not genetic?
Answer: Heritability. Without genetic basis, traits can't be passed to offspring.
Flashcard 8: Which condition is violated if all individuals survive and reproduce equally?
Answer: Differential fitness (differential survival and reproduction). Equal success means no selection pressure exists.
Flashcard 9: What is meant by "relative fitness"?
Answer: Fitness compared with other individuals in the same population. Fitness is always measured relative to population members.
Flashcard 10: Which condition is violated if all individuals survive and reproduce equally?
Answer: Differential fitness (differential survival and reproduction). Equal success means no selection pressure exists.
Flashcard 11: What is differential reproduction in the context of natural selection?
Answer: Individuals with advantageous traits produce more surviving offspring. Favorable traits lead to more offspring reaching reproductive age.
Flashcard 12: What is meant by "selection acts on phenotypes"?
Answer: The environment favors observable traits, not alleles directly. Environment selects based on what organisms look/act like.
Flashcard 13: What is the environment's role in natural selection?
Answer: It determines which phenotypes have higher fitness. Environmental conditions determine which traits are advantageous.
Flashcard 14: Limited application: If a trait is advantageous but not heritable, will natural selection cause evolution of that trait?
Answer: No, because allele frequencies will not change. Without heritability, beneficial traits can't increase in frequency.
Flashcard 15: Limited application: If a trait increases survival but reduces mating success, what determines its net selection?
Answer: Overall effect on total reproductive success (fitness). Trade-offs require evaluating overall reproductive success.
Flashcard 16: What is the key difference between natural selection and genetic drift?
Answer: Selection is nonrandom; drift is random change in allele frequencies. Selection has direction; drift is random sampling error.
Flashcard 17: What does "survival of the fittest" mean in precise biological terms?
Answer: Those with higher fitness leave more surviving offspring. Fitness measures reproductive success, not physical prowess.
Flashcard 18: Which outcome defines evolution by natural selection over time?
Answer: Increased frequency of alleles that improve fitness in that environment. Beneficial alleles become more common over successive generations.
Flashcard 19: What is meant by "natural selection is not goal-directed"?
Answer: It has no foresight; it favors traits beneficial in current conditions. Selection responds to current conditions, not future needs.
Flashcard 20: What is the difference between adaptation and acclimation?
Answer: Adaptation is genetic across generations; acclimation is within-lifetime change. Adaptation requires genetic change; acclimation is physiological adjustment.
Flashcard 21: What does the term "fitness" mean in evolutionary biology?
Answer: Relative reproductive success in a given environment. Not physical strength, but reproductive output compared to others.
Flashcard 22: What is meant by "heritable variation"?
Answer: Trait differences caused by genes that can be passed to offspring. Genetic basis ensures traits can be transmitted to next generation.
Flashcard 23: What is a common misconception about need and evolution that you must avoid?
Answer: Individuals do not evolve traits because they need them. Traits don't evolve because organisms want them.
Flashcard 24: What is the correct sequence of events in natural selection?
Answer: Variation → heritability → competition → differential reproduction → allele change. Standard order from initial variation to evolutionary change.
Flashcard 25: Identify the correct statement: selection creates variation or selection sorts existing variation?
Answer: Selection sorts existing heritable variation. Selection filters existing traits; mutation creates new variation.
Flashcard 26: What is a selective advantage?
Answer: A trait that increases fitness relative to other variants. Beneficial trait compared to alternatives in same environment.
Flashcard 27: What is meant by "relative fitness"?
Answer: Fitness compared with other individuals in the same population. Fitness is always measured relative to population members.
Flashcard 28: What is a selection coefficient in general terms?
Answer: A measure of the strength of selection against a genotype. Quantifies how strongly selection acts against certain genotypes.
Flashcard 29: Which condition is violated if a trait difference is purely environmental and not genetic?
Answer: Heritability. Without genetic basis, traits can't be passed to offspring.
Flashcard 30: What is the role of overproduction of offspring in natural selection?
Answer: Creates competition because not all offspring can survive and reproduce. Limited resources force competition, enabling selection to act.