Topic 19 Introduction to Animals

Question 1

What are animals

Answer 1

Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers

Question 2

radial symmetry

Answer 2

no front and back, or left and

right

Question 3

Radial animals are often

Answer 3

sessile or planktonic (drifting or weakly swimming)

Question 4

Cephalization

Answer 4

the development of a head with sensory organs

Question 5

Bilateral symmetry is associated with

Answer 5

cephalization, specialized appendages for directional movement, more active and have a central nervous system

Question 6

Bilaterally symmetrical animals have a

Answer 6

− Right and left side

Question 7

During development, embryonic (germ) cell layers give rise to these tissues

Answer 7

Ectoderm endotherm

Question 8

Ectoderm

Answer 8

is the germ layer covering the embryo’s surface (gives rise to skin and nerves)

Question 9

Endoderm

Answer 9

the innermost germ layer and lines the developing digestive tube, the archenteron

Question 10

Diploblastic animals have

Answer 10

two embryonic cell layers (ectoderm and

endoderm)

Question 11

Triploblastic animals have

Answer 11

an additional intervening mesoderm (meso = middle) layer that gives rise to muscles and other organs

Question 12

Bilateral animals are _blastic

Answer 12

triblastic

Question 13

coelom

Answer 13

arises during embryonic development of the mesoderm and contain coelomic fluid

Question 14

Most triploblastic animals possess a _____ body cavity

Answer 14

fluid-filled body cavity

Question 15

body cavity

Answer 15

a fluid-filled space or compartment in an animal body where internal organs develop

Question 16

hemocoel.

Answer 16

forms between the mesoderm and the endoderm