Ground tissue system or fundamental tissue
A tissue of mostly parenchyma cells that makes up the bulk of a young plant and fills the
space between the dermal and vascular tissue systems.
Growth factors
A protein that must be present in the extracellular environment (culture medium or animal
body) for the growth and normal development of certain types of cells.
Guard cell
A specialized epidermal plant cell that forms the boundaries of the stomata.
Guttation
The exudation of water droplets caused by root pressure in certain plants.
Gymnosperms
A vascular plant that bears naked seeds not enclosed in any specialized chambers.
Gynoecium
The female reproductive organs of a flower; the pistil or pistils considered as a group.
Gynoecia
The female reproductive organs of a flower considered as a group; the pistil or pistils.
Compare androecium.
H
Habitat
The place in which individuals of a particular species can usually be found.
Habituation
A simple kind of learning involving a loss of sensitivity to unimportant stimuli, allowing an
animal to conserve time and energy.
Half chordate
Hemichordates ("half chordates") have some features similar to those of chordates.
Half-life
The average time required for the disappearance or decay of one-half of any amount of a
given substance.