Natural Selection Flashcards
What is natural selection?
favors individuals with traits that increase fitness. Over time, beneficial traits become more common.
What is fitness?
how long an individual can survive and how much they can reproduce.
What is stabilizing selection?
favors the average traits, reducing extremes.
What is Directional selection?
favors one extreme phenotype over others.
What is disruptive selection?
favors both extremes, selecting against intermediate traits.
What is balancing selection?
selection that maintains variation in a population.
What is heterozygote advantage?
individuals with two different alleles have survival advantage
What is negative frequency dependent selection?
rare traits are favored
What is spatial variation?
different environments favor different traits across locations. This maintains diversity since what works well in one place might not in another.
What is temporal variation?
the environment changes over time, so different traits are favored at different times. This preserves variation in the population.
What are some constraints of natural selection?
Trade-offs, environmental variability, history (evolution over time)
What is natural selection?
a mechanism of evolution where individuals with advantageous traits are more likely to survive, reproduce, and pass on those traits to offspring.
What is adaptation?
a trait or behavior that improves an organism’s ability to survive and reproduce in its environments. Adaptions arise from natural selection.
What conditions must be met for natural selection?
Variation, heritability, differential reproduction (fitness), and selective pressure.
What is environmental selection?
environmental conditions (climate, food availability) influence which traits are favorable.
what is sexual selection?
traits that improve an individual’s chances of mating are favored, even if they don’t improve survival.
what is intrasexual selection?
competition within the same sex (usually males) for access to mates. Individuals compete through physical fights or displays of dominance.
what is intersexual selection?
one (usually females) chooses mates based on certain desirable traits, like appearance or behavior.
explain kin selection
behaviors that increase the survival of related individuals (kin) are favored, as they still promote the survival of shared genes.
define altruism
a behavior that reduces individual fitness and increases the fitness of other individuals.
