ch. 33 diploblasts

Question 1

phylums of diploblastic animals

Answer 1

• phylum cnidaria
• phylum ctenophora

Question 2

classes of phylum cnidaria

Answer 2

• class hydrozoa
• class scyphozoa
• class anthozoa

Question 3

characteristics of cnidarian animals

Answer 3

• radial symmetry
• ecto and endoderm
• gastrovascular cavity - extracellular digestion, incomplete gut
• single opening for mouth/anus
• true nerve cells arranged in nerve net

Question 4

2 variations in body plan of diploblasts

Answer 4

1. sessile polyp
2. motile medusa

Question 5

sessile polyp

Answer 5

tubular body with tentacles surrounding opening (mouth/anus)

Question 6

motile medusa

Answer 6

umbrella-shaped body with mouth on underside surrounded by tentacles

Question 7

sessile

Answer 7

stuck to one place, attached to substrate

Question 8

polyp

Answer 8

small growth with a stalk

Question 9

motile

Answer 9

moving or movable

Question 10

how do cnidarians eat

Answer 10

• carnivores
• use tentacles to capture prey

Question 11

what do cnidocytes contain?

Answer 11

nematocysts
- have hairlike trigger - cnidocil
- some sticky while others sting

Question 12

gastrovascular cavity of cnidarians

Answer 12

acts as hydrostatic skeleton against which contractile fibers can work to cause movement

Question 13

how are movements coordinated in cnidarians?

Answer 13

a non centralized nerve net

Question 14

class hydrozoa

Answer 14

“water animal”
- obelia

Question 15

class scyphozoa

Answer 15

“cup/can animal”
- jelly fish

Question 16

class anthozoa

Answer 16

“flower animal”
- corals and anemones
- form symbiotic relationships with colorful algae
secrete hard exoskeleton

Question 17

phylum ctenophora

Answer 17

“comb bearer”
- comb jellies

Question 18

characteristics of phylum ctenophora

Answer 18

• 2 long tentacles w/o stinging cells
• colloblasts
• cnidocytes in only one species
• complete gut - mouth and anus
• sensory organ
• hermaphroditic
• bioluminescent

Question 19

colloblasts

Answer 19

secrete sticky substance
- blast - to lay down
- collo - glue

Question 20

how many species of plylum Ctenophora have cnidocytes

Answer 20

one species

Question 21

sensory organ of ctenophora

Answer 21

calcareous particles settle in low points and act as orientation cues