Glossary | H

Habitat
environment in which a plant or animal lives; its home
Halophytes
plants that can grow in soils with a high salt content
Haustoria
slender portion of leaf or stem modified for twinning; a tendril
Hectocotylus
one of arms of most male cephalopods such as an octopus that is modified to transfer spermatophores from a male to a reproductive female
Hemoglobin
iron-containing pigment in red blood cells that conveys oxygen to tissues
Herbivore
animal adapted to subsist solely or mainly on plant food
Home range
area in which an animal lives
Homoeothermic
warm-blooded; body temperature controlled internally and maintained at a constant level; endothermic
Hydra
small jelly animals with a polyp form that are found only in fresh water; colonies are shaped like feathers or very small trees
Hydrodynamics
branch of physics that studies fluids in motion and the forces that affect motion
Hydroid
colony of polyps growing on a common stalk; found only in salt water; form colonies shaped like feathers or very small areas
Hydromedusae
small jellies usually less than 25mm (1 in)
Hydrophone
microphone submerged in water
Hydrozoan
class of Phylum Cnideria that includes hydroids, hydra, and the Portuguese man-of-war