Glossary

Glossary: G

gallery forest

Luxuriant forest lining the banks of waterways.

gamma diversity

See diversity - gamma.

ganglion

a bundle of nervous tissue containing many synapses and cell-bodies and contained within a sheath of connective tissue. Most ganglia (plural) occur outside of the central nervous system.

gas exchange

the process of exchanging gases from the environment with gases resulting from metabolism inside an animal's body across a gas exchange surface, such as the exchange surfaces of gills and lungs.

gemmule

a dormant, tough-coated cluster of cells produced by freshwater sponges for development in more favorable conditions.

generation (or generation time)

A period of time characteristic of an animal species and/or population that can be calculated as: The average age of parents in the population (used in the criteria for the new (1996) IUCN Red Data List categories), or the average age at first breeding

genitalia

genotype

genotypic

Referring to the genetic make-up of an organism.

See also: phenotype

genus (plural genera)

A taxonomic division that generally refers to a group of animals which are similar in structure and descent but are not all able to breed among themselves. For example, the lion, leopard and tiger all belong to the genus Panthera.

germinate

To begin to grow.

gestation

The process of carrying young inside the body before birth; the period from implantation of the embryo in the uterus to birth.

girdle

pelvic and pectoral girdles are the portion of vertebrate skeletons made up of the pelvic bones (pelvic girdle) and the scapula and clavicle (pectoral girdle).

granivore

an animal that mainly eats seeds

grazer

An herbivore that feeds on grasses (compare browser).

gregarious

Tending to associate with other animals of its kind; habitually living with other animals of its kind.

guano

excrement of seabirds or bats

guard hair

Part of the coat of some animals consisting of longer, stiffer hairs which lie outside and support the warmer, softer underfur.