Selection by humans for desired traits. Also called domestication or breeding.
In sexual selection, the competition for attention from the opposite sex.
In sexual selection, fights or aggressive displays between same-sex individuals of the same species; contests usually determine possession of territory or mates.
When selection pressures favor one extreme of the trait distribution.
When the average form of the trait is selected against while either extreme is unaffected.
The probability that an individual will contribute its genes to the next generation.
The different physical forms a trait may have. Long necks and short necks are examples of morphs.
The theory holding that competition exists within species, determining which species live to have offspring, and pass their traits on to those offspring.
A trait that exists in several different morphs is polymorphic.
When selection pressures favor the average form of the trait.
The selection of traits based on their role in courtship and mating.
A particular characteristic of an individual plant or animal.