Q₁₀. Temperature coefficient. The increase in the rate of a process (expressed as a multiple of initial rate) produced by raising temperature of 10°C. Often between two and three for biological, as for many chemical processes.

Qo₂. Term used for measurement of respiration. Oxygen uptake in microlitres (μl) per milligram dry weight per hour.

Quadrat. Square of vegetation (standard size is one metre square) chosen at random for study of composition of vegetation in a selected area.

Quadrate. A paired bone in the upper jaw of bony fishes, amphibians, reptiles, and birds that articulates with the lower jawbone. It is absent in mammals, being reduced to a small bone (the incus) in middle ear.

Qualitative inheritance. A type of inheritance in which expression of a particular character differs sharply amongst individuals of a species (discontinuous variation), e.g. sex. Depends on action of a few genes of major effect.