Ch. 27 - Animals

Question 1

When did animals originate?

Answer 1

700 mill years ago

Question 2

edicaran biota

Answer 2

an early group of soft-bodied multicellular eukaryotes that make up the earliest fossils

Question 3

sponges are what phylum?

Answer 3

porifera

Question 4

filter feeders

Answer 4

they filter out food particles suspended in the water as they draw it through their body

Question 5

basal animals

Answer 5

lie near the root of the phylogenetic tree

Question 6

tissues

Answer 6

groups of similar cells that act as a functional unit

Question 7

choanocytes

Answer 7

collar cells, flagellated feeding cells found in sponges

Question 8

amoebocytes

Answer 8

named for the use of pseudopodia, cells that move around the sponge body and transfer food and carry the nutrients to cells

Question 9

cnidarians

Answer 9

jellies, etc

Question 10

eumetazoans

Answer 10

true animals, members of a clade of animals that have tissues

Question 11

gastrovascular cavity

Answer 11

a cavity with a single opening in the body of certain animals that functions in both the digestion and distribution of nutrients, both a mouth and anus

Question 12

bilaterians

Answer 12

an enormous clade whose members have a complete digestive tract and a two-sided bilaterally symmetric form

Question 13

body plan

Answer 13

a particular set of morphological and developmental traits

Question 14

radial symmetry

Answer 14

symmetry in which the body is shaped like a pie or barrel, lacking a left and right side

Question 15

bilateral symmetry

Answer 15

animal has two axes of orientation

Question 16

dorsal

Answer 16

top

Question 17

ventral

Answer 17

bottom

Question 18

anterior

Answer 18

front

Question 19

posterior

Answer 19

back

Question 20

ectoderm

Answer 20

the outermost germ layer that gives rise to the outer covering and sometimes the nervous system, inner ear and lens of the eye

Question 21

endoderm

Answer 21

innermost germ layer, gives rise to the lining of the digestive tract/cavity and organs such as the liver and lungs in vertebrates

Question 22

mesoderm

Answer 22

the middle germ layer, only in bilaterates, forms the muscles and other organs between the digestive tract and outer covering

Question 23

body cavity

Answer 23

a fluid or air filled space located between the digestive tract and outer body wall

Question 24

arthropod

Answer 24

a segmented, molting bilateral animal with a hard exoskeleton and jointed appendages

Question 25

95% of animals are

Answer 25

invertebrates

Question 26

chordates

Answer 26

bilateral animals in Deuterostomia, animals that at some point during their development have a notochord, a dorsal, hollow nerve cord, pharyngeal slits or clefts, and a muscular, post-anal tail

Question 27

notochord

Answer 27

a flexible rod that provides skeletal support

Question 28

dorsal, hollow nerve cord

Answer 28

a structure that develops into the brain and spinal cord

Question 29

pharyngeal slits/clefts

Answer 29

structures that function in filter feeding, like gills or as parts of the head

Question 30

gnathostomes

Answer 30

jawless vertebrates, only two lineages survive today, hagfishes and lampreys

Question 31

chondrichthyans

Answer 31

vertebrates with skeletons made mostly of cartilage, ex. sharks and rays

Question 32

ray-finned fishes

Answer 32

member of the class actinopterygii, aquatic osteichthyans with fins supported by long, flexible rays, ex. tuna/bass/herring

Question 33

lobe-fins

Answer 33

clade osteichthyans, having rod-shaped muscular fins, the group includes coelacanths, lungfishes and tetrapods

Question 34

tetrapods

Answer 34

vertebrates with limbs and digits, once they got on land

Question 35

cuticle

Answer 35

an exoskeleton constructed from layers of protein and chitin, the body is completely covered by this

Question 36

amphibian

Answer 36

member of the tetrapod class amphibia, ex. salamander, frog, etc

Question 37

amniotes

Answer 37

a group of tetrapods whose extant members are reptiles and mammals

Question 38

amniotic egg

Answer 38

an egg that contains specialized membranes that functions in protection, nourishment and gas exchange

Question 39

what are the four membranes of the amniotic egg

Answer 39

amnion, chorion, yolk sac and allantois

Question 40

reptiles

Answer 40

the clade of amniotes that includes lizards, snakes, turtles, birds, etc

Question 41

ectothermic

Answer 41

they absorb external heat as their main source of body heat

Question 42

endothermic

Answer 42

capable of maintaining body temperature through metabolic activity

Question 43

mammals

Answer 43

amniotes that have hair and mammary glands

Question 44

synapsids

Answer 44

a member of an amniote clade distinguished by a single hole on each side of the skull

Question 45

monotremes

Answer 45

egg-laying mammals

Question 46

marsupials

Answer 46

mammals with a pouch

Question 47

eutherians

Answer 47

placental mammals