biology vocab words, 25-29

mesoderm

third cell layer formed in the developing embryo

acoelomate

body plan of an organism that can be divided along any plane, through a central axis, into roughly equal halves

radial symmetry

animal that has three cell layers, with a digestive tract but no body cavities

blastula

single layer of cells that forms a fluid-filled ball during early development

deuterostome

animal in which the mouth does not develop from the opening in the gastrula

ectoderm

layer of cells on the outer surface of the gastrula

bilateral symmetry

body plan of an organism that can be divided down its length into similar right and left halves

coelom

body cavity completely surrounded by mesoderm

sessile

describes organism that dont move from place to place

ectoderm

the embryonic layer that forms the skin and nervous tissue

endoderm

the animals digestive tract forms from the

flatworm

which animal has bilateral symmetry

more muscular control

animals with bilateral symmetry find food and mates and avoid predators more efficiently because they have

filter feeding

sponges get their food by

hematocyst

coiled threadlike tubes that are sticky or barbed or that contain toxins, Cnidarians capture prey this way

Gastrovascular cavity

digestion in cnidarians takes place in the

pharynx

during feeding, planarians extend a tubelike, muscular organ, called the

scolex

a parasitic tapeworm has a knob shaped head called a

external fertilization

in................., fertilization occurs outside the animals body after eggs and sperm are released

internal fertilization

in.................., eggs remain inside the animals body and sperm are carried to the eggs

polyp

is the tube shaped body form with a mouth surrounded by tentacles

medusa

is the sexual form of a cnidarian that has a body for like an umbrella with tentacles hanging down

proglottids

a tapeworm has reproductive organs in segments called

flagellated protists

the collar cells of sponges are similar to

corals

a group of cnidarians that provide food and shelter for many kinds of animals are the

planarian

a...................... has a muscular tube called the pharynx

sponge

which is an acoelomate animal

gizzard

annelids have a digestive organ called a

mantle

in bivalves,the ............... is a membrane that sticks to both shells and forms siphons that are used for drawing in and expelling water

closed circulatory system

an animal whose blood moves throughout its body within blood vessels has a

setae

tiny bristles protruding from each segment of a segmented worm are called

false

in shelled mollusks, the radula secretes the shell

false

bivalves obtain food by predation

true

the excretory structures in mollusks are called nephridia

false

gastropods have two shells

molting

shedding of the old exoskeleton

mandible

jaw of an arthropod

gills

aquatic arthropods exchange gases through

6

how many pairs of jointed appendages do arachnids have