Chapter 33 - Introduction to Invertebrates

Question 1

What are invertebrates?

Answer 1

animals that lack a backbone

Question 2

What phylum are sponges in?

Answer 2

Porifera

Question 3

What are filter feeders?

Answer 3

aquatic animals that capture food particles suspended in the water that passes through their body

Question 4

What is the cavity where water is drawn through pores in filter feeders?

Answer 4

spongocoel

Question 5

What is the opening to the spongocoel that water flows out of?

Answer 5

osculum

Question 6

What characteristic of most animals do sponges lack?

Answer 6

tissues

Question 7

What are choanocytes?

Answer 7

flagellated collar cells in sponges that generate a water current and ingest suspended food

Question 8

What is the mesohyl layer?

Answer 8

a gelatinous noncellular layer between two cell layers of a sponge

Question 9

What are amoebocytes?

Answer 9

totipotent cells found in the mesohyl that play roles in digestion and manufacture of skeletal fibers

Question 10

What does totipotent mean?

Answer 10

Totipotent cells can become any cell at any time.

Question 11

What are hermaphrodites?

Answer 11

each individual functions as both male and female; ex. sponges

Question 12

What clade are animals with true tissues in?

Answer 12

Eumetazoa

Question 13

Name the characteristics of Cnidarians.

Answer 13

sessile and motile; diploblastic; radial; sac-like with gastrovascular cavity; single opening; carnivores that use tentacles to capture prey

Question 14

What the gastrovascular cavity?

Answer 14

a central digestive compartment

Question 15

What is a polyp?

Answer 15

a sessile Cnidarian that adheres to the substrate by the aboral end of its body

Question 16

What is a medusa?

Answer 16

a motile, free-swimming Cnidarian that has a bell-shaped body with its mouth on the underside

Question 17

What are cnidocytes?

Answer 17

cells unique to Cnidarians that function in defense and capture of prey; have nematocysts

Question 18

What are nematocysts?

Answer 18

organelles of cnidocytes that eject a stinging thread

Question 19

What part of the cnidarians act as a hydrostatic skeleton?

Answer 19

the gastrovascular cavity

Question 20

What do hydrostatic skeletons do?

Answer 20

allow contractile fibers to move against

Question 21

What two clades did Phylum Cnidaria diverge into?

Answer 21

Medusozoa and Anthozoa

Question 22

What do Medusozoans include?

Answer 22

all cnidarians that produce a medusa including scyphozoans, cubozoans, and hydrozoans

Question 23

What are hydras?

Answer 23

freshwater cnidarians that exist only in polyp form and reproduce asexually by budding