dominant

dominant
1. (in genetics) Describing the allele that is expressed in the phenotype when two different alleles of a gene are present in the cells of an organism. For example, the height of garden peas is controlled by two alleles, ‘tall’ (T) and ‘dwarf’ (t). When both are present (Tt), i.e. when the cells are heterozygous, the plant is tall since T is dominant and t is recessive. See also codominance; incomplete dominance.

2. (in ecology) Describing the most conspicuously abundant and characteristic species in a community. The term is usually used of a plant species in plant ecology; for example, pine trees in a pine forest.

3. (in animal behaviour) Describing an animal that is allowed priority in access to food, mates, etc., by others of its species because of its success in previous aggressive encounters. Less dominant animals frequently show appeasement behaviour towards a more dominant individual, so overt aggression is minimized. In a stable group there may be a linear dominance hierarchy or peck order (so called because it was first observed in domestic fowl), with each animal being subservient to those above it in the hierarchy and taking precedence over those below it.