Ch.23 Animals 1: Major Invertebrate Groups

Front 1

Muticelled heterotroph with unwalled cells. Most ingest food and are motile during at least part of the life cycle.

Back 1

Animal

Front 2

Having paired structures so the right and left halves are mirror images.

Back 2

Bilateral Symmetry

Front 3

Evolutionary trend toward having a concentration of nerve and sensory cells at the head end.

Back 3

Cephalization

Front 4

Body cavity lined with tissue derived from mesoderm.

Back 4

Coelom

Front 5

Lineage of bilateral animals in which the second opening on the embryo surface develops into a mouth.

Back 5

Deuterostomes

Front 6

Outermost tissue layer of an animal embryo.

Back 6

Ectoderm

Front 7

Innermost tissue layer of an animal embryo.

Back 7

Endoderm

Front 8

Animal that does not have a backbone.

Back 8

Invertebrate

Front 9

Middle tissue layer of a three-layered animal embryo.

Back 9

Mesoderm

Front 10

Lineage of bilateral animals in which the first opening on the embryo surface develops into a mouth.

Back 10

Protostomes

Front 11

Unlined body cavity around the gut.

Back 11

Pseudocoelom

Front 12

Having parts arranged around a central axis, like the spokes of a wheel.

Back 12

Radial Symmetry

Front 13

Having a body composed of similar units that repeat along its length.

Back 13

Segmentation

Front 14

Hypothesis that the first animals evolved from a colonial protist.

Back 14

Colonial Theory of Animal Origins

Front 15

Group of tiny marine animals having a simple asymmetrical body and a small genome; considered an ancient lineage.

Back 15

Placozoans

Front 16

Animal that makes both eggs and sperm.

Back 16

Hermaphrodite

Front 17

Sexually immature stage in some animal life cycles.

Back 17

Larva

Front 18

Aquatic invertebrate that has no tissues or organs and filters food from the water.

Back 18

Sponge

Front 19

Animal that filters food from water around it.

Back 19

Suspension feeders

Front 20

Radially symmetrical invertebrate with two tissue layers; uses tentacles with stinging cells to capture food.

Back 20

Cnidarian

Front 21

Stinging cell unique to cnidarians

Back 21

Cnidocyte

Front 22

A saclike gut that also functions in gas exchange

Back 22

Gastrovascular Cavity

Front 23

Of soft-bodied invertebrates, a fluid-filled chamber that contractile cells exert force on.

Back 23

Hydrostatic Skeleton

Front 24

Decentralized mesh of nerve cells that allows movement in cnidarians.

Back 24

Nerve Net

Front 25

Bilaterally symmetrical invertebrate with organs but no body cavity; for example, a planarian or tapeworm.

Back 25

Flatworm (Phylum Platyhelminthes)

Front 26

Segmented worm with a coelom, complete digestive system and closed circulatory system.

Back 26

Annelid (Phylum Annelida)

Front 27

Circulatory system in which blood flows through a continous network of vessels; all materials are exchanged across the walls of those vessels.

Back 27

Closed circulatory system

Front 28

Mollusk with a hinged two-part shell.

Back 28

Bivalve

Front 29

Predatory mollusk with a closed circulatory system; moves by jet propulsion.

Back 29

Cephalopod

Front 30

Mollusk in which the lower body is a broad "foot". Include the only terrestrial mollusks.

Back 30

Gastropod

Front 31

Invertebrate with a reduced coelom and a mantle.

Back 31

Mollusk (Phylum Mollusca)

Front 32

System in which hemolymph leaves vessels and seeps through tissues before retuning to the heart.

Back 32

Open Circulatory System

Front 33

Of some arthropods, sensory structure on the head that detects touch and odors.

Back 33

Antenna

Front 34

Invertebrate with jointed legs and a hard exoskeleton that is periodically molted.

Back 34

Arthropod (Phylum Arthropoda)

Front 35

Periodic shedding of an outer body layer or part.

Back 35

Molting

Front 36

Cylindrical worm with a pseudocoelom. Has a cuticle that they periodically molt.

Back 36

Roundworm (Phylum Nematoda)

Front 37

Of some arthropods, a motion-sensitive eye made up of many image-forming units.

Back 37

Compound Eye

Front 38

Hard external parts that muscles attach to and move.

Back 38

Exoskeleton

Front 39

Dramatic remodeling of body form during the transition from larva to adult.

Back 39

Metamorphosis

Front 40

Land-dwelling arthropods with no antennae and four pairs of walking legs; spiders, scorpions, mites, and ticks.

Back 40

Arachnids

Front 41

Arthropod group with specialized feeding structures (chelicerae) and no antennae; arachnids and horseshoe crabs.

Back 41

Chelicerates

Front 42

Mostly marine arthropods with a calcium-hardened cuticle and two pairs of antennae; for example lobsters, crabs, krill, and barnacles.

Back 42

Crustaceans

Front 43

Long-bodied terrestrial arthropods with one pair of antennae and many similar segments; centipedes and millipedes.

Back 43

Myriapods

Front 44

Most diverse arthropod group; members have six legs, two antennae, and, in some groups, one or two pairs of wings.

Back 44

Insects

Front 45

Invertebrates with a water-vascular system and hardened plates and spines embedded in the skin or body.

Back 45

Echinoderms

Front 46

Of echinoderms, a system of fluid-filled tubes and tube feet that function in locomotion.

Back 46

Water-Vascular System

Front 47

No body cavity

Back 47

Acoelomate

Front 48

Cavity fully lined by mesoderm. True body cavity.

Back 48

Coelomate

Front 49

Describes an animal that only contains a two layered body.

Back 49

Diploblastic

Front 50

Describes an animal that contains a three layered body.

Back 50

Triploblastic

Front 51

The body plan of a cnidarian where the gastrovascular and tentacles cavity faces up.

Back 51

Polyp

Front 52

In mollusks, a tough tongue hardened by chitin (the material it's based of)

Back 52

Radula

Front 53

The collar cells that line the inner surface of porifera/sponges.

Back 53

Choanocytes

Front 54

In mollusks, the area between the shell where material that creates the shell is secreted.

Back 54

Mantle

Front 55

The anterior end of certain flatworms, bearing suckers and hooks for attachment.

Back 55

Scolex

Front 56

Secreted covering at a body surface in some animals.

Back 56

Cuticle

Hint 56

Crustaceans and roundworms contain this covering which they molt.

Front 57

A cnidarian body plan in which the gastrovascular cavity faces down.

Back 57

Medusa

Hint 57

Example: the body plan of a jellyfish.

Front 58

Fixed in one place, immobile.

Back 58

Sessile