32

Question 1

what are animals?

Answer 1

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

Question 2

Bodies are held together by structural proteins such as

Answer 2

collagen

Question 3

what is their nutritional mode

Answer 3

Chemoheterotrophs

Question 4

This ancestor may have resembled modern ______ , protists that are the closest living relatives of animals

Answer 4

choanoflagellates

Question 5

At the beginning of the ______ animals underwent a rapid diversification.

Answer 5

Cambrian period (535 to 525 million years ago)

Question 6

bilaterians

Answer 6

organisms that have the following traits:
– Bilaterally symmetric form
– Complete digestive tract
– One-way digestive system

Question 7

Kingdom Animalia is

Answer 7

Monophyletic and very diverse

Question 8

body plan

Answer 8

set of morphological and developmental traits, integrated into a functional whole
– Symmetry: absent, present (radial or bilateral)
– Tissues: collections of specialized cells
– Germ layers: diploblasts or triploblasts
– Body cavities

Question 9

radial symmetry

Answer 9

Parts radiate from the center, so any slice through the central axis divides into mirror images.

Question 10

Bilateral symmetry

Answer 10

Only one slice can divide left and right sides into mirror-image halves

Question 11

Bilaterally symmetrical animals have:

Answer 11

1. Dorsal (top side)
2. Ventral (bottom side)
3. Anterior (head/front)
4. Posterior (tail/back)
5. Cephalization (development of a head)

Question 12

tissues

Answer 12

Tissues are collections of specialized cells isolated from other tissues by membranous layers

Question 13

During development, ______ give rise to the tissues and organs of the animal embryo

Answer 13

three germ layers

Question 14

ectoderm

Answer 14

is the germ layer covering the embryo’s surface, that forms the nervous system and the skin

Question 15

Endoderm

Answer 15

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

Question 16

Mesoderm

Answer 16

is the middle layer that forms the heart, kidneys, and muscles.

Question 17

_____animals have ectoderm and endoderm

Answer 17

Diploblastic

Question 18

_______ animals also have an intervening mesoderm layer; these include all bilaterians

Answer 18

triploblastic

Question 19

Most triploblastic animals possess a

Answer 19

body cavity

Question 20

A true body cavity is called a ______ and is

derived from mesoderm

Answer 20

coelom

Question 21

_____ are animals that possess a true coelom

Answer 21

Coelomates

Question 22

Advantages of a coelom:

Answer 22

• Creates a medium for circulation
• Makes space for internal organs
• A hydrostatic skeleton • fluid-filled chamber
• allows movement

Question 23

pseudocoelomates

Answer 23

animals that have one

have a body cavity lined by tissue from mesoderm and by tissue derived from endoderm

Question 24

acoelomate

Answer 24

lack a body cavity between the digestive cavity and outer body wall

Question 25

protostome development

Answer 25

(examples: molluscs, annelids) eight-cell stage, spiral and determinate mouth develops from blastopore

Question 26

Deuterostome development

Answer 26

(examples: echinoderm, chordates) radial and indeterminate anus develops from blastopore

Question 27

indeterminate

Answer 27

embryo cells retain the capacity to develop into a complete embryo

Question 28

In gastrulation, the developing digestive tube of an embryo initially forms as a blind pouch, the

Answer 28

archenteron

Question 29

Five key points about Animal Phylogenetic Tree:

Answer 29

1. All animals share a common ancestor 2. Sponges are basal animals 3. Eumetazoa (“true animals”) is a clade of animals with true tissues 4. Most animal phyla belong to the clade Bilateria 5. There are three major clades of bilaterian animals, all of which are invertebrates, animals that lack a backbone, except Chordata, which are classified as vertebrates because they have a backbone

Question 30

Ecdysozoa

Answer 30

bilateral invertebrates characteristics shared by nematodes, arthoprods secrete exoskeletons

Question 31

Lophotrochozoa

Answer 31

2 different features observed- lophophore and trochophore

Question 32

lophohpore

Answer 32

a crown of ciliated tentacles that function in feeding

Question 33

trochophore larva

Answer 33

includes molluscs and annelids

Question 34

one of the characteristics unique to animals is

Answer 34

gastrulation

Question 35

the distinction between sponges and other animal phyla is based mainly on the absence vs presence of

Answer 35

tissues

Question 36

which of the following was probably the least important factor in bringing about the cambrian explosion

Answer 36

the movement of animals onto land

Question 37

based on the tree in figure 32.11 which statement in false?

Answer 37

coelomate flatworms are more closely related to the echinoderms than to annelids

Question 38

Animals probably evolved from colonial protists. How do animals differ from these protist ancestors?

Answer 38

Animals have more specialized cells.

Question 39

The animal phylum most like the protists that gave rise to the animals is _____.

Answer 39

Porifera

Question 40

A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A postdoctoral student thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus?

Answer 40

look for cell walls under a microscope

Question 41

Unlike other animals, sponges _____.

Answer 41

lack true tissues

Question 42

Symmetry is one of the most basic characteristics of animals. The phylum that has a different symmetry from the other three phyla listed is the ____________.

Answer 42

Porifera

Question 43

Which of the following is associated with bilateral symmetry?

Answer 43

cephalization

Question 44

"Cephalization" refers to having _____.

Answer 44

a head end

Question 45

cephalization

Answer 45

the concentration of sense organs, nervous control, etc., at the anterior end of the body, forming a head and brain, both during evolution and in the course of an embryo's development.

Question 46

How do cnidarians and ctenophores differ from all other eumetazoans?

Answer 46

Cnidarians and ctenophores are radially symmetrical.

Question 47

All animals with bilateral symmetry have _______ germ tissue layer(s).

Answer 47

three

Question 48

Ectoderm can give rise to _______; mesoderm can give rise to ______; endoderm can give rise to _________.

Answer 48

the central nervous system ... muscle ... the lining of the digestive tube

Question 49

Which of the following is NOT a characteristic of cnidarians?

Answer 49

mesoderm

Question 50

The difference between pseudocoelomates and coelomates is that pseudocoelomates _________, whereas coelomates _________.

Answer 50

have a body cavity partially lined with tissue derived from mesoderm ... have a body cavity completely lined with tissue derived from mesoderm

Question 51

A true coelom is ____________.

Answer 51

a body cavity lined with mesoderm

Question 52

One of the primary developmental/anatomical characteristics distinguishing the major animal phyla is the condition of the body cavity. A pseudocoelomate animal is one in which the body cavity is _____.

Answer 52

bounded partly by mesoderm

Question 53

The presence of a coelom is advantageous because _____.

Answer 53

it allows room for the development and movement of internal organs

Question 54

Coelomates gave rise to _____

Answer 54

protostomes and deuterostomes

Question 55

Coeloms _____.

Answer 55

evolved independently more than once

Question 56

Zoologists place chordates and echinoderms on one major branch of the animal phylogenetic tree, and mollusks, annelids, and arthropods on another major branch. Which of the following is a basis for this separation?

Answer 56

how the body cavity is formed

Question 57

The zygotes of many protostomes undergo ______ and ______ cleavage.

Answer 57

spiral ... determinate

Question 58

Which of the following is NOT a difference between protostomes and deuterostomes?

Answer 58

the presence of a body cavity

Question 59

All of the following are deuterostomes EXCEPT ____________.

Answer 59

mollusks

Question 60

An animal with a true coelom that has ____________ cleavage must be a____________.

Answer 60

indeterminate, radial ... deuterostome

Question 61

Protostomous animals are those in which the _____.

Answer 61

blastopore forms the mouth

Question 62

The phrase "Cambrian explosion" refers to _____.

Answer 62

the rapid adaptive radiation that gave rise to most extant animal phyla

Question 63

Why are echinoderms a model species for studying embryonic development?

Answer 63

1. Has a more rapid development and life history. 2. External fertilization 3. deuterostome development The sea urchin embryo has long been used as a model organism to address many questions in developmental biology. The straightforward artificial spawning, fertilization and rearing, and embryo optical transparency make this organism a great resource. Also, the simple organization. Sea urchins undergo radial, reductive cleavage.