Table 1-4 Quiz

Body symmetry

the arrangement of parts of an organism

asymmetry

lacking regularity or pattern in the arrangement of body parts

bilateral symmetry

having similar body parts divided by an imaginary axis. the right side is similar to the left but top diff. from bottom

radial symmetry

having similar parts radiating from the central axis of the body in a plane or cylinder. top diff. from bottom.

body segmentation

the division of body parts into like units

segmented

having a series of body parts/segments, one following the other (often alike)

nonsegmented

having no repetition of body parts

body location

the orientation of body features

anterior

head end, sensory organs

posterior

hind end, excretory vent

dorsal

upper/back

ventral

lower/front, covering most digestive organs

lateral

side

skeleton

support structure that gives the body shape and place for attaching tissues and organs

exoskeleton

a hard shell outside the epidermis, tissues, and organs are attached to the inner surfaces of the shell

endoskeleton

hard plates or bones inside the epidermis with organs and tissues attached to outer surfaces

hydrostatic skeleton

cavities inside the body which become rigid when filled with fluid under pressure

digestive tract

parts and arrangements of digestive structures

saclike tract

having a digestive pouch, mouth and anus are the same opening

complete digestive tract

having a mouth, digestive tube, an anus

nervous system

parts and arrangements of nerve structures

dorsal nerve cord

runs along the dorsal side of the animal above the digestive tract

ventral nerve cord

runs along ventral side of the animal ventral to the digestive tract

nerve net

runs through the animal (3d spider web)

radial nerve cord

fans out in rays from the center of animal

ganglion,ganglia

small swelling of the nerve cord, may be anywhere on cord

ladderlike nerve cord

may form one row/branch into as many as 3 parts each controlled by ganglia

brain

enlarged anterior part of the nerve cord

respiratory structure

types of body parts where respiration takes place

skin/epidermis

outermost layer of cells, allows oxygen to pass directly into animal (no special organs for respiration)

gills

organs that remove dissolved oxygen from water

lungs

organs that remove oxygen from the air

unique features

features in each phylum not found in any other. often indicated in name of phylum

economic importance

value to humans (money, attitude of people and societies)

environmental niche

place of an organism in relation to other organisms in its environment, including role in food chain and habitat

solitary

living singly

colonial

living in groups/clusters often attached to each other

sessile

attached to the bottom, unable to move around

motile

able to move from place to place by crawling/swimming