chapter 44

Question 1

Poriferans

Answer 1

an aquatic invertebrate animal of the phylum Porifera; a sponge.

Question 2

Cnidarians

Answer 2

a phylum characterized by radial symmetry, two germ tissues in the embryo, a closed internal gastric cavity, and well-developed tissues but not organs

Question 3

radial symmetry

Answer 3

symmetry around a central axis, as in a starfish or a tulip flower

Question 4

bilateral symmetry

Answer 4

symmetry on both sides of a midline, animals with bilateral symmetry have a distinct head and tail, marking front and back, with a single plane of symmetry running between them at the midline

Question 5

Bilateria

Answer 5

the monophyletic group of animals with bilateral symmetry

Question 6

acoelomates

Answer 6

a bilaterian without a body cavity

Question 7

coelomates

Answer 7

a body cavity surrounding the gut

Question 8

pseudocoelomates

Answer 8

an invertebrate that has a fluid-filled body cavity not lined with mesoderm tissue

Question 9

protostomes

Answer 9

a bilaterians in which the blastopore, the first opening to the internal cavity of the developing embryo, becomes the mouth

Question 10

deuterostomes

Answer 10

a bilaterian in which the blastopore, the first opening to the internal cavity of the developing embryo, becomes the anus

Question 11

lophotrochozoans

Answer 11

are a taxon of protostome animals

Question 12

ecdysozoans

Answer 12

a group of protostome animals

Question 13

choanocytes

Answer 13

a type of cell that lines the interior surface of a sponge

Question 14

Eumetazoa

Answer 14

the monophyletic group of all animals other than sponges

Question 15

gastric cavity

Answer 15

in cnidarians, a closed internal sit where extracellular digestion and excretion take place

Question 16

epidermis

Answer 16

in mammals, the outer layer of skin, which serves as a water-resistant, protective barrier

Question 17

endodermis

Answer 17

the inner lining of the cnidarian body

Question 18

mesoglea

Answer 18

in cnidarians, a gelatinous mass enclosed in by the epidermis and endodermis

Question 19

ctenophores

Answer 19

comb-jellies; species in this phylum have a radial body plan but a flow-through gut

Question 20

Annelida

Answer 20

a phylum of worms that have a cylindrical body with distinct segments and a bilaterian body plan

Question 21

Cambrian explosion

Answer 21

a transition period in geologic time during which the body pans characteristic of most bilaterina phyla developed

Question 22

Mollusca

Answer 22

a monophyletic group distinguished by a mantle, which plays a major role in movement, skeleton-building, breathing, and excretion

Question 23

gastropods

Answer 23

a group of mollusks consisting of snails and slugs

Question 24

cephalopods

Answer 24

a monophyletic group of mollusks, including squid, cuttlefish, octopus, and chambered nautilus, with distinctive adaptations such as well-developed eyes and muscular tentacles that capture prey and sense the environment

Question 25

bivalves

Answer 25

mollusks that includes clams, oysters, and mussels; they have an enclosing skeleton in which two hard shells are connected by a flexible hinge

Question 26

Arthropoda

Answer 26

a monophyletic group of animals that included insects and contains more than half of all known animal species, distinguished by their segmented bodies and jointed legs

Question 27

chelicerates

Answer 27

one of the four main groups of arthropods, including spiders and scorpions, chelicerates have pincer-like claws and are the only arthropods that lack antennae

Question 28

myriapods

Answer 28

one of the four main groups of arthropods, including centipedes and millipedes; distinguished by their many pairs of legs

Question 29

crustaceans

Answer 29

one of the four main groups of arthropods; including lobsters, shrimp, and crabs; distinguished by two pairs of antennae and their branched legs or other appendages

Question 30

metamorphosis

Answer 30

the process in some animals in which the body changes dramatically at key stages in development

Question 31

spiracles

Answer 31

an opening in the exoskeleton on either side of an insect's abdomen through which gases are exchanged

Question 32

tracheae

Answer 32

an internal system of tubes in insects that branch from openings along the abdominal surface into smaller airways, directing oxygen to and removing carbon dioxide form respiring tissues

Question 33

Chordata

Answer 33

one of the three major phyla of deuterostomes, this group included vertebrates and closely related invertebrate animals such as sea squirts

Question 34

Echinodermata

Answer 34

one of the three major phyla of deuterosomes, defined by five-part symmetry; this group includes sea urchins and sea stars

Question 35

pharynx

Answer 35

the region of the throat that connects the nasal and mouth cavities; in hemichordates, a tube that connects the mouth and the digestive tract

Question 36

pharyngeal slits

Answer 36

a vertical opening separated form other slits by stiff rods of protein in the pharynx of hemichordates

Question 37

dorsal nerve cord

Answer 37

a nerve cord that develops in a location dorsal to the notochord, this embryonic feature is unique to chordates

Question 38

water vascular system

Answer 38

a series of fluid-filled canals that permit bulk transport of oxygen and nutrients in echinoderms

Question 39

tube feet

Answer 39

small projections of water vascular system that extend outward from the body surface and facilitate locomotion, sensory perception, food capture, and gas exchange in echinoderms

Question 40

vertebrates

Answer 40

a subphylum of Chordata, distinguished by a bony cranium that protects the grain and (unless lost through evolution), a vertebral column

Question 41

craniates

Answer 41

a subphylum of Chordata, distinguished by a bone cranium that protects the brains

Question 42

notochord

Answer 42

in chordates, a stiff rod of collagen and other proteins that runs along the back and provides support for the axis of the body

Question 43

vertebral column

Answer 43

a skeletal structure in vertebrates that functionally replaces the embryonic notochord that supports the body

Question 44

vertebrae

Answer 44

the series of hard bony segments making up the jointed skeleton that runs along the main axis of the body in vertebrates

Question 45

neural tube

Answer 45

in chordates, a cylinder of embryological tissue that develops into a dorsal nerve cord

Question 46

myotomes

Answer 46

in chordates, any one of a series of segments that organizes the body musculature

Question 47

hagfish

Answer 47

one of the earliest-branching craniates, with a cranium built of cartilage but no jaws; hagfish feed on marine worms and dead and dying sea animals

Question 48

lampreys

Answer 48

one of the earliest-branching craniates, with a cranium and vertebral column built of cartilage but no jaws; many lampreys live parasitically, sucking body fluids from fish prey

Question 49

Chondrichthyes

Answer 49

cartilaginous fish, a monophyletic group that includes about 800 species of sharks, rays and chimaeras

Question 50

Osteichthyes

Answer 50

bony fish that have a cranium, jaws, and mineralized bones, there are about 20,000-25,000 species

Question 51

fleshy-finned fishes

Answer 51

have muscles and Class Sarcopterygii

Question 52

coelacanth

Answer 52

a genus of two species of lobe-finned fish found off the coast of Africa and thought to have been extinct for 80 million years but which is still living today; along with lungfish, he nearest relative of tetrapod

Question 53

lungfish

Answer 53

several species of lobe-finned fish that use a simple lung to survive periods when their watery habitat dries by burying themselves in moist med and breathing air; along with coelacanths, the nearest relative of tetrapods

Question 54

Tetrapoda

Answer 54

a monophyletic group of animals whose last common ancestor had four limbs; this group includes amphibians, lizards, turtles, crocodilians, birds and mammals

Question 55

Amphibians

Answer 55

a monophyletic group of vertebrates, including frogs and salamanders, with an aquatic larval form with gills and an adult terrestrial form that usually has lungs

Question 56

amniotic egg

Answer 56

an egg that can exchange gases while retaining water, permitting amniotes to reproduce in dry terrestrial habitats that amphibian eggs cannot tolerate

Question 57

amniotes

Answer 57

the group of vertebrate animals that produce amniotic eggs, this group includes lizards, snakes, turtles, and crocodilians

Question 58

Mammalia

Answer 58

a class of vertebrates distinguished by body hair and mammary glands from which they feed their young

Question 59

monotremes

Answer 59

are basal mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals

Question 60

marsupials

Answer 60

a group of mammals that includes kangaroos, koalas, and opossums; their young are born at an early stage of development and must crawl to a pouch where mammary glands equipped with nipples provide them with milk

Question 61

placental mammals

Answer 61

a mammal that provides nutrition to the embryo through the placenta, a temporary organ that develops in the uterus; placental mammals include carnivores, primates, hooved mammals, and whales