Relate Variation to Selection Pressure - Biology

Alleles contributing to that phenotype tend to increase over generations. Higher fitness genotypes become more common over time.

Selection acts only on existing heritable variation. Selection cannot create variation; it only filters what exists.

The disease is a selection pressure against that genotype. Disease creates differential survival based on genotype.

A heritable trait becomes more common across generations. Adaptation involves genetic change across generations.

Heritable variation that affects fitness. Without heritable variation affecting fitness, no evolution occurs.

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

They create new alleles that can be acted on by selection. Without mutations, there would be no variation to select from.

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

An environmental factor that affects survival or reproduction. These pressures determine which traits are advantageous.

Heritable differences in DNA/alleles among individuals. This forms the raw material for natural selection to act upon.

A trait increases mating success despite survival costs. Sexual selection can oppose survival-based natural selection.

Traits improving juvenile survival increase in frequency. Early survival strongly impacts lifetime reproductive success.

Alleles contributing to that phenotype tend to increase over generations. Higher fitness genotypes become more common over time.

Selection does not favor either phenotype (no directional change). Equal fitness means no selective advantage for either form.

Offspring resemble parents for the trait across environments. Heritability shows genetic rather than environmental control.

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

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

A trait can be beneficial in one environment and harmful in another. Fitness depends entirely on environmental context.

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

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

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

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

Selection is a mechanism; evolution is allele frequency change. Selection is the cause; evolution is the measured outcome.

A trait increases fitness in one way but decreases it in another. Evolution often involves compromises between competing needs.

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

Selection filters existing heritable variation; it does not create it. Selection sorts existing variation; it doesn't generate novelty.

Antibiotic acts as a selection pressure favoring resistant cells. Antibiotics create directional selection for resistance.

Trait variation must be heritable and affect fitness. Both conditions are necessary for evolutionary change.

Selection favors alleles that increase speed. Speed becomes directly linked to survival and reproduction.