Ch 32 Introduction to Animal Evolution

Question 1

Characteristics of animals

Answer 1

1) Multicellular eukaryotes
2) Heterotrophs
3) Cells lack cell walls
4) Bodies held together by structural proteins (collagen)

Question 2

Collagen comprises much of what?

Answer 2

The fibers in connective tissues

Question 3

What is the most abundant protein in the bodies of animals?

Answer 3

Collagen

Question 4

How do most animals reproduce?

Answer 4

Sexually

Question 5

Cleavage

Answer 5

Rapid cell division of the zygote

Question 6

What tissues are unique, defining characteristics of animals?

Answer 6

1) Muscle tissue

2) Nervous tissue

Question 7

Tissue

Answer 7

Groups of cells that have a common structure, function, or both

Question 8

How do animal body plans vary?

Answer 8

According to the organization of the animal’s tissues

Question 9

During development, what gives rise to the tissues and organs of the animal embryo?

Answer 9

Germ layers

Question 10

Blastula

Answer 10

Formed by cell cleavage

Question 11

Ectoderm

Answer 11

The germ layer covering the embryo’s surface

Question 12

Endoderm

Answer 12

The innermost germ layer

Question 13

The endoderm lines what?

Answer 13

The archenteron

Question 14

Archenteron

Answer 14

Developing digestive tube

Question 15

Diploblastic animals

Answer 15

Possess an ectoderm and endoderm

Question 16

Three diploblastic animals

Answer 16

1) Corals
2) Jellyfish
3) Comb jellies

Question 17

Triploblastic animals

Answer 17

Posses an ectoderm, mesoderm, and endoderm

Question 18

Bilaterian

Answer 18

Possess bilateral symmetry

Question 19

Cephalization

Answer 19

Organization of senses and locomotion toward a head region

Question 20

All multicellular animals posses what kind of symmetry?

Answer 20

Bilateral symmetry

Question 21

Larva

Answer 21

Sexually immature and anatomically distinct from the adult

Question 22

Juvenile

Answer 22

Resembles an adult, but is not sexually mature

Question 23

Animal diversity arose from what?

Answer 23

A hypothesized ancestor

Question 24

How long ago did the hypothesized ancestor of animals live?

Answer 24

Between 675 and 800 mya

Question 25

The hypothesized ancestor of animals resemble what?

Answer 25

Modern choanoflagellates

Question 26

Choanoflagellates

Answer 26

Protists that are the closest living relatives of animals

Question 27

Cambrian explosion

Answer 27

Marks the earliest fossil appearance of many major groups (phyla) of living animals

Question 28

How long ago was the Cambrian explosion?

Answer 28

535 to 525 mya

Question 29

Three main hypotheses regarding the cause of the Cambrian explosion:

Answer 29

1) New predator-prey relationships 2) A rise in atmospheric oxygen 3) The evolution of the Hox gene complex

Question 30

What organisms posses Hox genes?

Answer 30

Most animals, and only animals

Question 31

Hog genes

Answer 31

Regulate many other genes and control the development of body form

Question 32

Despite being highly conserved, the Hox family of genes produces what?

Answer 32

A wide variety of animal morphologies

Question 33

Most species are what?

Answer 33

Arthropods

Question 34

How many species of arthropods are there?

Answer 34

Over one million

Question 35

How many of all known animals of arthropods?

Answer 35

About 3/4

Question 36

Protosome cell proliferation

Answer 36

Cell proliferation following fertilization is by spiral cleavage

Question 37

Deuterostome cell proliferation

Answer 37

Cell proliferation following fertilization is by radial cleavage

Question 38

Protostome coelom development

Answer 38

Coelom forms within the middle tissue germ layer

Question 39

Deuterostome coelom development

Answer 39

Coelom forms from outpocketing of the middle tissue germ layer

Question 40

Protostome initial opening

Answer 40

Initial opening into the gut becomes the mouth

Question 41

Deuterostom initial opening

Answer 41

Initial opening into the gut becomes the anus

Question 42

What distinguishes protostomes and deuterostomes?

Answer 42

Embryonic development

Question 43

Coelom

Answer 43

The body cavity surrounding the gut

Question 44

What was previously the basis for major classification within the protostomes?

Answer 44

Coelom

Question 45

Protostome groups previously based on coelom have been shown to be what?

Answer 45

Polyphyletic

Question 46

Phylum Placozoa

Answer 46

Possibly the simplest animals with the smallest genome

Question 47

How many genes are possessed within the genome of placozoans?

Answer 47

11,500 genes

Question 48

How many cell types are possessed by placozoans?

Answer 48

Only four cell types

Question 49

Phylum Placozoa lack what?

Answer 49

1) Symmetry 2) Organs 3) Muscles 4) Nervous system