Chapter 33 Vocab

Front 1

Define: alimentary canal

Back 1

A digestive tract consisting of a tube running between a mouth and an anus.

Front 2

Define: ammonite

Back 2

A shelled cephalopod that was the dominant invertebrate predator for millions of years until the end of the Cretaceous period.

Front 3

Define: amoebocyte

Back 3

An amoeba-like cell that moves by pseudopodia, found in most animals; depending on the species, may digest and distribute food, dispose of wastes, form skeletal fibers, fight infections, and change into other cell types.

Front 4

Define: arthropod

Back 4

A segmented coelomate with a chitinous exoskeleton, jointed appendages, and a body formed of distinct groups of segments.

Front 5

Define: book lung

Back 5

An organ of gas exchange in spiders, consisting of stacked plates contained in an internal chamber.

Front 6

Define: chelicera

Back 6

One of a pair of clawlike feeding appendages characteristic of cheliceriforms.

Front 7

Define: cheliceriform

Back 7

An arthropod that has chelicera, and a body divided into a cephalothorax and an abdomen. Living cheliceriforms include sea spiders, horseshoe crabs, scorpions, ticks, and spiders.

Front 8

Define: choanocyte

Back 8

A flagellated feeding cell found in sponges. Also called a collar cell, it has a collar-like ring that traps food particles around the base of its flagellum.

Front 9

Define: closed circulatory system

Back 9

A circulatory system in which blood is confined to vessels and is kept separate from the interstitial fluid.

Front 10

Define: cnidocyte

Back 10

A specialized cell for which the phylum Cnidaria is named; contains a capsule containing a fine coiled thread, which, when discharged, functions in defense and prey capture.

Front 11

Define: complete metamorphosis

Back 11

The transformation of a larva into an adult that looks very different, and often functions very differently in its environment, than the larva.

Front 12

Define: crustacean

Back 12

A member of a subphylum of arthropods that includes lobsters, crayfish, crabs, shrimps, and barnacles.

Front 13

Define: cuticle

Back 13

The exoskeleton of an arthropod, consisting of layers of protein and chitin that are variously modified for different functions... A tough coat that covers the body of a nematode

Front 14

Define: decapod

Back 14

A member of the group of crustaceans that includes lobsters, crayfish, crabs, and shrimp.

Front 15

Define: exoskeleton

Back 15

A hard encasement on the surface of an animal, such as the shell of a mollusc or the cuticle of an arthropod, that provides protection and points of attachment for muscles.

Front 16

Define: foot

Back 16

One of the three main parts of a mollusc; a muscular structure usually used for movement.

Front 17

Define: gastrovascular cavity

Back 17

An extensive pouch that serves as the site of extracellular digestion and a passageway to disperse materials throughout most of an animal’s body.

Front 18

Define: hermaphrodite

Back 18

An individual that functions as both male and female in sexual reproduction by producing both sperm and eggs.

Front 19

Define: hexopod

Back 19

An insect or closely related wingless arthropod.

Front 20

Define: incomplete metamorphosis

Back 20

A type of development in certain insects, such as grasshoppers, in which the young (called nymphs) resemble adults but are smaller and have different body proportions. The nymph goes through a series of molts, each time looking more like an adult, until it reaches full size.

Front 21

Define: invertebrate

Back 21

An animal without a backbone. Invertebrates make up 95% of animal species.

Front 22

Define: mandible

Back 22

One of a pair of jaw-like feeding appendages found in myriapods, hexapods, and crustaceans.

Front 23

Define: mantle

Back 23

A fold of tissue in molluscs that drapes over the visceral mass and may secrete a shell.

Front 24

Define: mantle cavity

Back 24

A water-filled chamber that houses the gills, anus, and excretory pores of a mollusc.

Front 25

Define: medusa

Back 25

The floating, flattened, mouth-down version of the cnidarian body plan. The alternate form is the polyp.

Front 26

Define: mesohyl

Back 26

A gelatinous region between the two layers of cells of a sponge.

Front 27

Define: molting

Back 27

A process in arthropods in which the exoskeleton is shed at intervals, allowing growth by the production of a larger exoskeleton.

Front 28

Define: myriapod

Back 28

A terrestrial arthropod with many body segments and one or two pairs of legs per segment. Millipedes and centipedes comprise the two classes of living myriapods.

Front 29

Define: nematocyst

Back 29

A stinging, capsule-like organelle in a cnidocyte.

Front 30

Define: open circulatory system

Back 30

A circulatory system in which fluid called hemolymph bathes the tissues and organs directly and there is no distinction between the circulating fluid and the interstitial fluid.

Front 31

Define: osculum

Back 31

A large opening in a sponge that connects the spongocoel to the environment.

Front 32

Define: parthenogenesis

Back 32

A type of reproduction in which females produce offspring from unfertilized eggs.

Front 33

Define: phoronids

Back 33

A tube-dwelling marine lophophorate.

Front 34

Define: planarian

Back 34

A free-living flatworm found in unpolluted ponds and streams.

Front 35

Define: polyp

Back 35

The sessile variant of the cnidarian body plan. The alternate form is the medusa.

Front 36

Define: radula

Back 36

A straplike rasping organ used by many molluscs during feeding.

Front 37

Define: spongocoel

Back 37

The central cavity of a sponge.

Front 38

Define: suspension-feeder

Back 38

An aquatic animal, such as a clam or a baleen whale, that sifts small food particles from the water.

Front 39

Define: trochophore larva

Back 39

Distinctive larval stage observed in annelids and molluscs.

Front 40

Define: tube foot

Back 40

One of numerous extensions of an echinoderm’s water vascular system. Tube feet function in locomotion, feeding, and gas exchange.

Front 41

Define: visceral mass

Back 41

One of the three main parts of a mollusc, containing most of the internal organs.

Front 42

Define: water vascular system

Back 42

A network of hydraulic canals unique to echinoderms that branches into extensions called tube feet, which function in locomotion, feeding, and gas exchange.