Biology Ch. 24 Vocabulary

Question 1

Animal without a backbone; between 95 and 99 percent of animal species are invertebrates

Answer 1

Invertebrate

Question 2

Hard or tough outer covering of many invertebrates that provides support, protects body tissues, prevents water loss, and protects the organism from predation

Answer 2

Exoskeleton

Question 3

Internal skeleton that protects internal organs, provides support for the organism’s body, and can provide an internal brace for muscles to pull against

Answer 3

Endoskeleton

Question 4

Animal with an endoskeleton and a backbone.

Answer 4

Vertebrate

Question 5

Animal that produces both sperm and eggs in its body; generally at different times.

Answer 5

Hermaphrodite

Question 6

Fertilized egg formed when a sperm cell penetrates an egg

Answer 6

Zygote

Question 7

Type of fertilization that occurs when sperm and egg combine inside an animal’s body.

Answer 7

Internal fertilization

Question 8

Type of fertilization that occurs when sperm and egg combine outside an animal’s body.

Answer 8

External fertilization

Question 9

Fluid-filled ball of cells formed by mitotic cell division of the embryo.

Answer 9

Blastula

Question 10

Two-cell-layer sac with an opening at one end that forms from the blastula during embryonic development

Answer 10

Gastrula

Question 11

Inner layer of cells in the gastrula that develops into digestive organs ad the digestive tract lining

Answer 11

Endoderm

Question 12

Outer layer of cells in the gastrula that develops into nervous tissue and skin.

Answer 12

Ectoderm

Question 13

Layer of cells between the endoderm and the ectoderm that can become muscle tissue and tissue of the circulatory, respiratory, and execretory systems

Answer 13

Mesoderm

Question 14

Balance or similarity in body structures of organisms

Answer 14

Symmetry

Question 15

Body plan that can be divided along any plane, through a central axis, into roughly equal halves

Answer 15

Radial symmetry

Question 16

Body plan that can be divided into mirror images along only one plane through the central axis

Answer 16

Bilateral symmetry

Question 17

Toward the head end of an animal with bilateral symmetry

Answer 17

Anterior

Question 18

Away from the head end of animal with bilateral symmetry

Answer 18

Posterior

Question 19

Tendency to concentrate sensory organs and nervous tissue at an animal’s anterior end.

Answer 19

Cephalization

Question 20

Backside of an animal with bilateral symmetry

Answer 20

Dorsal

Question 21

Underside or belly of an animal with bilateral symmetry

Answer 21

Ventral

Question 22

Fluid-filled body cavity completely surrounded by mesoderm

Answer 22

Coelom

Question 23

Fluid-filled body cavity between the mesoderm and the endoderm

Answer 23

Pseudocoelom

Question 24

Animal with a solid body that lacks a fluid-filled body cavity between the gut and the body wall.

Answer 24

Acoelomate

Question 25

Coelomate animal whose mouth develops from the opening in the gastrula

Answer 25

Protostome

Question 26

Coelomate animal whose anus develops from the opening in the gastrula

Answer 26

Deuterostome

Question 27

Organism that filters small particles from water to get its food

Answer 27

Filter feeder

Question 28

Organism permanently attached to one place

Answer 28

Sessile

Question 29

Nematocyst-containing stinging cell on a cnidarians tentacle

Answer 29

Cnidocyte

Question 30

Capsule whose threadlike tube contains poison and barbs and is discharged when prey touches a cnidarian

Answer 30

Nematocyst

Question 31

In cnidarians, the space surrounded by an inner cell layer, where digestion take place

Answer 31

Gastrovascular cavity

Question 32

Nervous system that conudcts impulses in cnidarians and echinoderms

Answer 32

Nerve net

Question 33

Tube-shaped, sessile body form of cnidarians

Answer 33

Polyp

Question 34

Umbrella-shaped, free-swimming body form of cnidarians.

Answer 34

Medusa