Chap. 32

Question 1

tissues

Answer 1

groups of similar cells that act as a functional unit

Question 2

cleavage

Answer 2

after fertilization forms a zygote, a succession of mitotic cell divisions without cell growth between the divisions
-animal sexual reproduction

Question 3

blastula

Answer 3

cleavage leads to the formation of a multicellular embryonic stage called a blastula, which in many animals takes the form of a hollow ball

Question 4

gastrulation

Answer 4

the layers of embryonic tissues that will develop into adult body parts are produced creating a Gastrula
- after blastula

Question 5

larva

Answer 5

a sexually immature form of an animal that is morphologically distinct from the adult, usually eats different food, and may even have a different habitat than the adult

Question 6

metamorphosis

Answer 6

Animal larvae eventually undergo metamorphosis, a developmental transformation that turns the animal into a juvenile that resembles an adult but is not yet sexually mature.

Question 7

defining characteristics of animals

Answer 7

muscle and nerve cells are central to the animal lifestyle.

Question 8

collagen

Answer 8

proteins external to the cell membrane that provide structural support to animal cells and connect them to one another

Question 9

Hox genes

Answer 9

regulate the development of
body form
-make sure right body parts form in the right places

Question 10

choanoflagellates

Answer 10

the closest living relatives of animals

Question 11

Ediacaran

Answer 11

early group of mostly soft-bodied multicellular eukaryotes
-early animal fossil record

Question 12

Cambrian explosion

Answer 12

(535–525 million years ago) marks the earliest fossil appearance of many major groups of living animals
-Ediacaran life-forms declined

Question 13

bilaterians

Answer 13

most of the fossils from the Cambrian explosion are of bilaterians
-have the following
traits:
* Bilaterally symmetric form
* Complete digestive tract
* One-way digestive system

Question 14

Arthropods

Answer 14

were the first animals to adapt to terrestrial habitats

Question 15

Paleozoic Era (541–252 Million Years Ago)

Answer 15

cambrian explosion

Question 16

Mesozoic Era (252–66 Million Years Ago)

Answer 16

Coral reefs emerged, dinosaurs were the dominant terrestrial
vertebrates, The first mammals emerged, Flowering plants and insects diversified

Question 17

Cenozoic Era (66 Million Years Ago to the Present)

Answer 17

mass extinctions of both
terrestrial and marine animals, rise of large mammalian herbivores

Question 18

body plan

Answer 18

a particular set of morphological and developmental traits that are integrated into a functional whole

Question 19

radial symmetry

Answer 19

the type of symmetry found in a
flowerpot
- have not and bottom but no front, back, left, or right.

Question 20

bilateral symmetry

Answer 20

The two-sided symmetry of a shovel
-humans

Question 21

bilateral symmetry different sides

Answer 21

dorsal (top) side and a ventral (bottom) side
* A right and left side
* Anterior (front) and posterior (back) ends

Question 22

whatre the germ layers

Answer 22

Ectoderm, Endoderm,

Question 23

Ectoderm

Answer 23

the germ layer covering the embryo’s surface

Question 24

Endoderm

Answer 24

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

Question 25

Diploblastic animals

Answer 25

have only ectoderm and endoderm * These include cnidarians and a few other groups

Question 26

Triploblastic animals

Answer 26

have ectoderm and endoderm and also have an intermediate tissue layer called mesoderm

Question 27

mesoderm

Answer 27

fills much of the space between the ectoderm and endoderm

Question 28

All bilaterally symmetrical animals have.... and are called....

Answer 28

- a mesoderm - triploblastic

Question 29

body cavity

Answer 29

a fluid- or air-filled space located between the digestive tract (endoderm) and the outer body wall (ectoderm)

Question 30

coelom

Answer 30

a body cavity that forms from tissue derived from mesoderm

Question 31

coelomates

Answer 31

Animals possessing coeloms are sometimes called coelomates

Question 32

hemocoel

Answer 32

a body cavity that forms between the mesoderm and endoderm

Question 33

pseudocoelomates

Answer 33

Animals with only a hemocoel once were called pseudocoelomates

Question 34

acoelomates

Answer 34

triploblastic animals lack a body cavity altogether

Question 35

Protostome development

Answer 35

develop mouth first then anus -spiral and determinate development

Question 36

Deuterostome development

Answer 36

develop anus first then mouth -humans -radial and indeterminate development

Question 37

body cavity functions

Answer 37

* Fluid cushions the suspended organs * Fluid acts like a skeleton against which muscles can work * The cavity enables internal organs to grow and move independently of the outer body wall

Question 38

determinate cleavage

Answer 38

development rigidly casts (“determines”) the developmental fate of each embryonic cell very early

Question 39

indeterminate cleavage

Answer 39

meaning that each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo

Question 40

archenteron

Answer 40

During gastrulation, an embryo’s developing digestive tube initially forms as a blind pouch, the archenteron, which becomes the gut

Question 41

deuterostome coelom development

Answer 41

the mesoderm buds from the wall of the archenteron to form the coelom

Question 42

protostome coelom development

Answer 42

the splitting of solid masses of mesoderm forms the coelom

Question 43

blastopore

Answer 43

forms during gastrulation and connects the archenteron to the exterior of the gastrula

Question 44

what does the blastopore become in protostome vs deuterostome

Answer 44

- In protostome development, the blastopore becomes the mouth - In deuterostome development, the blastopore

Question 45

Five important points about the relationships among living animals are....

Answer 45

* All animals share a common ancestor * Sponges are the sister group to all other animals * Eumetazoa (“true animals”) is a clade of animals with tissues * Most animal phyla belong to the clade Bilateria * There are three major clades of bilaterian animals, all of which are invertebrates, animals that lack a backbone, except Chordata, which includes vertebrates, animals with a backbone