BIO LAB Exam 3 Study Terms

protosome

a multicellular organism whose mouth develops first before its anus

deuterostome

a multicellular organsim whos anus develops before its mouth

asymmetry

the lack of symmetry

Radial symmetry

symmetry around a central axis

Bilateral Symmetry

symmetry where the right and left sides of an item are mirror images of each other

diploblast

organsims thatg develop from two primary germ layers, the ectoderm, and the endodoerm. they do not develop organs

Triploblast

organisms that develop from three cell layers, ectoderm, endoderm, and mesoderm,

which animals are triploblasts?

All except for sponges and coelenterates (jellyfish, corals, sea anenomes)

coelomate (coelem)

animals that possess a true coelom, fluid filled body cavity lined by mesoderm

acoelomate

animals that lack a coelom

pseudocoelomate

invertebrates that possess a fluid filled body cavity called a pseudocoelom, that is only partially lined by mesoderm

osculum

the large opening/pore on the body of the sponge in which water exits

spongocoel

the central, water filled cavity within a sponge’s body

gastrodermis

the inner cell layer of the gastrovascular cavity

epidermis

the outermost layer that serves as a protective barrier against the external environment

gasrtrovascular cavity

a simple digestive cavity that functions in both digestion and circulation

polyp

a body form found in phylum cnidaria. They are sessile, typically cylindrical, with one end fixed to a substrate and ther other, free w/ tentacles for feeding that face upwards

medusa

one of the body forms found in the phylum Cnidaria. It’s free swimming with an umbrella shaped body and trailing tentacles.

corona

the cilliated “crown” that is found in rotifers that is crucial for feeding and locomotion

pharynx

aka the throat, is a tube shaped passageway for air and food that connects the nasal cavity to the esophogas

scolex

the head end of a parasitic flatworm.

mantle cavity

acts as a respiratoory chamber and fiilter feeding area. Found in the phylum mollusks

mantle

a soft tissue layer that covers the body and internal organs of mollusks and brachiopods.

visceral mass

a region in mollusks that contains the majority of the animals internal organs. The “body” of the mollusk

radula

a unique feeding organ found in most mollusks (not bivalves) that serves as a tounge like structure for cutting food

metameres

the repeating body segments typically found in annelids

parapodia

paired, unjointed appendages that are used for locomotion, and respiration

Chaetae

briostles primarily used for locomotion that occur on annelid worms

tagmata

specialized groupings of segments in arthropods and some other animals

cephalothorax

the fused head and thorax region of some arthropods and certain crustaceans

spiracles

external openings on the bodies of certain animals (arthropods, insects, and some fish) that facilitate gass exchange

endoskeleton

the internal skeleton sustem that provides support and protection to the body

tube feet

small fluid filled appendages founbd in echinoderms like seastars and sea urchins

notochord

a flexible rod like structure found in the embryonic stages of all chordatea that provides support and is then replaced by the vertabral column

dorsal hollow nerve chord

a hollow tube of nervous tissue located on the dorsal side of the body above the notochord that later develops into the brain and spinal chord

pharyngeal gill slits

openinds in the pharynx, or throat, that connect to the outside