Kingdom Annimalia: Phylum Cnidaria

Question 1

Definition and 10 characteristics:

Answer 1

• Multicellular, diploblastic with stinging cells ex.jellyfish
  1) marine
  2) have no organs
  3) radially symmetrical
  4) non-motile
  5) Two types: polyp and Medusa
  6) No cephalization or segmentation
  7) nerve net between ectoderm and endoderm
  8) sense organs present are statocysts and occelli
  9) hydrostatic skeleton
  10) sexual reproduction by gametes

Question 2

Difference between polyp and Medusa

Answer 2

Polyp: cylindrical, sessile, attached from foot to rocks or algae. Tentacles surround mouth
Medusa: umbrella-shaped and free-floating. Mouth points downward and tentacles hang around

Question 3

What is a mesoglea?

Answer 3

• Thick layer of gelatinous material between the ectoderm and the endoderm

Question 4

What is a gastrovascular cavity?

Answer 4

• A digestive cavity lined with enzyme producing glandular cells of the endoderm. Extracellular digestion occurs here.

Question 5

What are cnidocytes?

Answer 5

• Cells which may contain poisonous sticky barbed nematocyles are which triggered to discharge by sensitive chidocils. Serve as defense.

Question 6

What are the 2 main classes of phylum Cnidaria?

Answer 6

1) class Hydrozoa ex. hydra
2) class Scyphozoa ex. Jellyfish

Question 7

Class Hydrozoa forms

Answer 7

Most are both polyp and medusa form.

Question 8

Class Scyphozoa forms:

Answer 8

Medusa form is aparent.
Polyp form is only present in larval stage.