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15 terms

Animals: Invertebrates

Biology Terms for invertebrates.
no definite shape; cannot be divided into equal parts
radial symmetry
have body parts arranged around a central axis; round
bilateral symmetry
body design in which there are equal right & left halves
sensory organs & nerves located near the front or head region
thin projections of tissue that are rich n blood vessels that allow for gas exchange
closed circulation
heart pumps blood throughout the body through a series of blood vessels
open circulation
heart pumps blood into a body cavity without the use of vessels
hydrostatic skeleton
cavity is filled with water to act as a support system
rigid external skeleton on the outside of an animals body
skeleton composed of a hard material such as bone that helps support an animals body
animal that possesses both male & female reproductive parts
external fertilization
egg & sperm unite outside the female's body
internal fertilization
egg & sperm unite inside the female's body
animal that does not possess a backbone
organism that does not move throughout its life & stays in one place