Evolutionary Agents
Often called "survival of the fittest", where individuals with advantageous traits reproduce more successfully.
Natural Selection
The process by which humans, rather than the environment, select for desirable traits in plants or animals.
Artificial Selection
This mode favors the average phenotype, such as human birth weights that are neither too high nor too low.
Stabilizing Selection
This agent increases genetic variety through random changes in DNA and is the only source of entirely new phenotypes.
Mutation
These four principles—Variation, Competition, Adaptation, and Selection—were proposed by this famous scientist.
Charles Darwin
This mode favors one extreme phenotype, causing the bell curve to shift in one direction.
Directional Selection
This occurs when the individuals move into or out of population, bringing or taking their alleles with them
Gene Flow
This occurs when more offspring are produced than the environment can support, leading to competition for resources.
Overpopulation
What is the major difference between Natural and Artificial selection?
In natural selection, the environment determines which traits are best for survival and reproduction. In artificial selection, humans intentionally choose and breed organisms for specific desirable traits.
Random fluctuations in allele frequencies that have a much larger impact on small populations than large ones.
Genetic Drift
An environmental factor, such as a predator or a change in climate, that determines which phenotypes are successful.
Selecting Agent
Why does competition occurs within population?
Competition occurs because of overpopulation, where more organisms are born than the environment has resources (like food and shelter) to support.
A specific type of genetic drift that occurs when a population's size is drastically reduced by a disaster like a flood or fire.
Bottleneck Effect
A biological phenomenon where a palatable (edible) species evolves to look like an unpalatable one to avoid predators.
Mimicry
What is the term for the environmental factors that determine which individuals survive?
The term for these environmental factors is selecting agents.