Glossary

Glossary: R

radial

1. Arranged like rays. 2. Radiating from or converging to a common center. 3. Moving or directed along a radius. 4. Near the radius (a bone) of the forearm. 5. Developing symmetrically around a central point.

radial symmetry

a kind of body symmetry where the animal is arranged around a central axis, examples are jellyfish and anemones.

radius

In anatomy: a long, slightly curved bone of the forearm of tetrapods. It is one of two bones found in tetrapod forearms and is located alongside the ulna, which is the other forearm bone.

radula

the rasping tongue found in most molluscs (Phylum Mollusca, snails, bivalves, and cephalopods).

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Climbing plants are also abundant. There is plenty of moisture and rain, but may be somewhat seasonal.

range

The geographical area over which an animal is distributed.

reef

structure produced by the piled-up skeletons of corals (animals in the Class Anthozoa). Coral reefs are found in warm, shallow oceans with few nutrients in the water. They form the basis for rich communities of other invertebrates, plants, and fish.

regenerate

to replace a lost or damaged organ or part through formation of new tissues.

relict

A persistent remnant of an otherwise extinct flora or fauna.

reproduction

the process of producing offspring.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

river

a large, natural body of running water

roe

the eggs or egg mass of fish or crustaceans.

ruminant

An animal with a specialized digestive system which includes chewing the cud.