Ch. 12

Question 1

vertebrate

Answer 1

animal with a backbone, only about 3% of animals have backbones

Question 2

invertebrate

Answer 2

animals lacking a backbone, about 97% of animals are invertebrates

Question 3

symmetry

Answer 3

arrangement of the individual body parts of an object, animals with bilateral symmetry have mirror image body parts, radial symmetry have body parts arranged in a circle around a central point, asymmetrical animals have no definite shape

Question 4

cnidarian

Answer 4

phylum of hollow-bodied, water-dwelling animals with stinging cells, radial symmetry, a body two layers thick, and both sexual and asexual reproduction

Question 5

polyp

Answer 5

vase-shaped body plan of a cnidarian, such as a hydra, that allows it to twist to capture pray and to somersault to a new location

Question 6

medusa

Answer 6

free-swimming, bell-shaped body plan of a cnidarian, such as a jellyfish, that allows it to drift with the ocean currents

Question 7

free-living

Answer 7

organism, such as a planarian, that doesn’t depend on one particular organism for food or a place to live

Question 8

parasite

Answer 8

organism, such as a tapeworm, that depends on its host for food and a place to live

Question 9

mollusk

Answer 9

soft-bodied invertebrate that has a mantle, a large muscular foot, a complete digestive system with two openings, and usually has a protective shell

Question 10

mantle

Answer 10

thin tissue layer covering a mollusk’s soft body, secretes the protective shell of those mollusks having a shell

Question 11

gills

Answer 11

organs that exchange oxygen and carbon dioxide with water

Question 12

radula

Answer 12

scratchy tongue-like organ in many mollusks that acts like a file with rows of teeth to break up food into smaller pieces

Question 13

open circulatory system

Answer 13

type of blood-circulation system in which the blood is not contained in vessels but instead surrounds the organs

Question 14

closed circulatory system

Answer 14

type of blood-circulatory system in which blood is carried through blood vessels

Question 15

arthropod

Answer 15

animals that have jointed appendages, such as an insect or a crustacean, that is classified by the number of body segments and appendages, and that has a protective exoskeleton

Question 16

appendage

Answer 16

jointed structures, such as legs, claws, and antennae, that grow from a body

Question 17

exoskeleton

Answer 17

lightweight body covering that protects and supports an arthropod’s body, prevents it from drying out, and is shed by molting

Question 18

metamorphosis

Answer 18

process is which insects change their body form as they mature, can be complete (egg, larva, pupa, and adult) or incomplete (egg, nymph, and adult)