One of several variants that can occupy a locus on a chromosome 

An organism that regulates the concentration of dissolved ions in its body fluids irrespective of changes in the external medium

Refers to a group of species that do not have one common ancestor species

The deep ocean floor, an expanse of low relief at depths of 4,000 to 6,000 meters

The 4,000 to 6,000 meter depth zone, seaward of the shelf-slope break

Given a change of a single parameter, a readjustment of the physiology of an organism reaching a new steady state 

Is the correctness of a measure when comparing to a known standard

The relative abundance of different age classes in a population

Non-reef-building (referring to scleractinian corals)

A variant of an enzyme type. These may be variants of a specific enzyme (e.g., cytochrome c) that are the products of a single genetic locus.