Chapter 33

Question 1

_______ are animals that lack a backbone

Answer 1

Invertebrates

Question 2

Except for sponges (basal organisms in phylum Porifera) and a few other groups, all animals have _______ and belong to the clade ________

Answer 2

tissues, Eumetazoa.

Question 3

Most animals are in the large, diverse clade ______

Answer 3

Bilateria

Question 4

Bilaterians (unlike sponges and cnidarians) have a ________ and a two-sided – bilaterally symmetric – form.

Answer 4

complete digestive tract,

Question 5

Animals in the phylum ______ are known informally as sponges

Answer 5

Porifera

Question 6

Sponges are ___________, capturing food particles suspended in the water that passes through their body

Answer 6

suspension feeders

Question 7

In sponges, water is drawn through pores into a central cavity called the _______ and out the sponge through a large opening called the _________

Answer 7

spongocoel, osculum

Question 8

__________, flagellated collar cells, generate a water current through the sponge and ingest suspended food

Answer 8

Choanocytes

Question 9

Most sponges are _________: Each individual functions as both male and female

Answer 9

hermaphrodites

Question 10

Phylum __________ is one of the oldest groups in the clade Eumetazoa

Answer 10

Cnidaria

Question 11

Cnidarians have diversified into a wide range of both sessile and motile forms including ___, ______, and ______

Answer 11

jellies, corals, and hydras

Question 12

Cnidarians exhibit a relatively simple ______ (have 2 developmental germ layers), radial body plan (exhibit radial symmetry)

Answer 12

diploblastic, radial body plan

Question 13

The basic body plan of a cnidarian is a sac with a central digestive compartment, the ____________. And a single opening functions as mouth and anus

Answer 13

gastrovascular cavity

Question 14

There are two variations on the Cnidarian body plan: the sessile ______ and motile ______

Answer 14

polyp, medusa

Question 15

A _____ adheres to the substrate by the aboral end (the end opposite the mouth) of its body; also extends tentacles waiting for prey (eg., hydras, sea anemones)

Answer 15

polyp, tentacles

Question 16

A _______ has a bell-shaped body with its mouth on the underside

Answer 16

medusa

Question 17

Cnidarians have tentacles are armed with _________, unique cells that function in defense and capture of prey

Answer 17

cnidocytes

Question 18

_________ are specialized organelles within cnidocytes that eject a stinging thread

Answer 18

Nematocysts

Question 19

Most ________(class of Cnidaria) alternate between polyp and medusa forms

Answer 19

hydrozoans

Question 20

The medusa is the predominant stage in the life cycle of most __________, and live among the plankton as jellies.

Answer 20

Scyphozoa

Question 21

Cnidaria class with complex eyes embedded in the fringe of their medusae, also equipped with highly toxic cndocytes.

Answer 21

Cubozoa

Question 22

Cnidaria class \_\_\_\_\_\_\_ includes the corals and sea anemones, and these cnidarians occur only as polyps
Corals often form symbioses with algae and secrete a hard external skeleton of calcium carbonate.

Answer 22

Anthozoa

Question 23

The overwhelming majority of the 1.3 million known animal species are_______, and most (Blank) are _______

Answer 23

bilaterians; invertebrates

Question 24

The clade _________ includes the flatworms, rotifers, ectoprocts, brachiopods, molluscs, and annelids

Answer 24

Lophotrochozoa

Question 25

Members of phylum _________ also called flatworms, are flattened dorsoventrally and have a gastrovascular cavity with one opening

Answer 25

Platyhelminthes

Question 26

Although flatworms undergo triploblastic development, they are _________ (no central cavity)

Answer 26

acoelomates

Question 27

The best-known rhabditophorans (free-living species) are ________ that have light-sensitive eyespots and more complex and cetrilized nerve nets. Hemaphrodies that can repordice sexually or asexually through fission.

Answer 27

planarians

Question 28

Two important groups of parasitic rhabditophorans are the __________ _______________

Answer 28

trematodes and the tapeworms

Question 29

___________ are parasites of vertebrates and lack a digestive system

Answer 29

Tapeworms

Question 30

The_________ (head), on tapeworms, contains suckers and hooks for attaching to the host

Answer 30

scolex

Question 31

______ are units that contain sex organs and form a ribbon behind the scolex

Answer 31

Proglottids

Question 32

Phylum ________ includes snails and slugs, oysters and clams, and octopuses and squids. Soft-bodied animals, but most are protected by hard shell.

Answer 32

Mollusca

Question 33

Many molluscs also have a water-filled________ and feed using a rasplike ________

Answer 33

mantle cavity; radula

Question 34

_________ are oval-shaped marine animals encased in an armor of eight dorsal plates

Answer 34

Chitons

Question 35

The most distinctive characteristic of _________ is torsion, which causes the animal’s anus and mantle to end up above its head; torsion is different from the coiling of a shell

Answer 35

gastropods

Question 36

________ are marine and include many species of clams, oysters, mussels, and scallops

Answer 36

Bivalves

Question 37

The mantle cavity of a bivalve contains ________ that are used for feeding as well as gas exchange

Answer 37

Gills

Question 38

Shelled _________ called ammonites were common but went extinct at the end of the Cretaceous 65.5 mya. The nautiluses survive today.

Answer 38

cephalopods

Question 39

Squids use their ________ to fire a jet of water, which allows them to swim very quickly

Answer 39

siphon

Question 40

________ have bodies composed of a series of fused rings with a true coelom.

Answer 40

Annelids

Question 41

__________ , named for relatively sparse chaetae bristles made of chitin, include earthworms, leeches

Answer 41

Oligochaetes

Question 42

Ecdysozoans are covered by a tough coat called a ________, | is shed or molted through a process called ecdysis

Answer 42

cuticle

Question 43

Nematodes, or __________

Answer 43

roundworms

Question 44

The ________ body plan consists of a segmented body, hard exoskeleton, and jointed appendages

Answer 44

arthropod

Question 45

The body of an arthropod is completely covered by the ______, an ________ made of layers of protein and the polysaccharide chitin

Answer 45

cuticle; exoskeleton

Question 46

Arthropods have an open circulatory system in which _________(body fluid which bathes tissues) is circulated into the spaces surrounding the tissues and organs

Answer 46

hemolymph

Question 47

Horseshoe crabs are surviving members of a rich diversity of _________ that once filled the seas.

Answer 47

chelicerates

Question 48

Most modern cheliceriforms are ________, which include spiders, scorpions, ticks, and mites

Answer 48

arachnids

Question 49

Arachnids have an abdomen and a cephalothorax (head + thorax), which has six pairs of appendages: the_________ (claw-like feeding appendages), the _________ (function in sensing, feeding, or reproduction), and four pairs of walking legs

Answer 49

chelicerae; pedipalps

Question 50

Gas exchange in spiders occurs in respiratory organs called_________(stacked plate-like structures contained in an internal chamber)

Answer 50

book lungs

Question 51

Subphylum__________includes millipedes and centipedes that have jaw-like __________

Answer 51

Myriapoda; mandibles

Question 52

Millipedes have many legs, with______ per trunk segment

Answer 52

two pairs

Question 53

Centipedes are carnivores | Centipedes have ________ of legs per trunk segment

Answer 53

one pair

Question 54

In _________ metamorphosis, the young, called nymphs, resemble adults but are smaller and go through a series of molts until they reach full size

Answer 54

incomplete

Question 55

Insects with _________ metamorphosis have larval stages known by such names as maggot, grub, or caterpillar

Answer 55

complete

Question 56

Isopods include terrestrial, freshwater, and marine species. _________ are all relatively large crustaceans and include lobsters, crabs, crayfish, and shrimp

Answer 56

Decapods

Question 57

Planktonic crustaceans include many species of _______, which are among the most numerous of all animals

Answer 57

copepods

Question 58

Echinoderms (phylum Echinodermata) include_______ and ________

Answer 58

sea stars: sea urchins

Question 59

___________ share developmental characteristics Radial cleavage, Formation of the anus from the blastopore (embryonic developmental germ layer). Also are defined primarily by DNA similarites.

Answer 59

Deuterostomes

Question 60

Echinoderms have a unique _______, a network of hydraulic canals branching into tube feet that function in locomotion and feeding

Answer 60

water vascular system

Question 61

Humans most frequently acquire trichinosis by

Answer 61

eating under cooked pork.

Question 62

Anatomy of a sea star, an echinoderm. Sea stars feed on bivalves by prying them open with their tube feet, ____________, and digesting their prey externally with digestive enzymes

Answer 62

everting their stomach

Question 63

Example of a _________ which has bilaterally symmetrical coelomates with segmented bodies ,is a lancelets

Answer 63

chordate