Jellyfish

Question 1

What are the classes of phylum Cnidaria?

Answer 1

• class Hydrozoa
• class Anthozoa
• class Scyphozoa

Question 2

General characteristics of Cnidaria phylum:

Answer 2

• radially symmetrical
• polyp and medusa stage present
• gastrovascular cavity with one opening
• have nematocysts eg. stinging cells
• have nerve net
• planula larva via sexual or asexual reproduction

Question 3

Feeding using nematocysts:

Answer 3

• barbs and filament used to pierce and entangle the prey are called nematocysts
• cnidocyte cell houses the nematocysts
• triggered by chemical and physical stimulus
• cnidocil is trigger in all classes EXCEPT Anthozoa

Question 4

Feeding using tentacles:

Answer 4

• retract and transport the prey to mouth

Question 5

Feeding using gastrovascular cavity:

Answer 5

• gastrovascular cavity is where initial digestion occurs

- digestion occurs intracellularly

Question 6

Feeding using symbiosis:

Answer 6

• can use symbiotic algae cells that grow in endoderm or mesoglea

Question 7

Locomotion in jellyfish:

Answer 7

• some polyps have limited movement

- medusa swim by jet propulsion

Question 8

How do jellies reproduce?

Answer 8

• gametes released into water

- embryo develops into planula larva

Question 9

Characteristics of class Hydrozoa

Answer 9

• most marine or some freshwater
• mostly polyps that are colonial but some are single
• both polyp and medusa stage
• has planula larva

Question 10

Characteristics of class Scyphozoa

Answer 10

• polyp stage reduced eg. called scyphistoma
• goes from scyphistoma to strobilating polyp to ephyra and then medusa
• has planula larva

Question 11

Characteristics of class Anthozoa

Answer 11

• no medusa stage
• may be solitary or colonial
• solitary = sea anemone
• colonial = coral

Question 12

Characteristics of phylum Ctenophora

Answer 12

• biradial symmetry
• diploblastic
• nerve net present
• 8 rows of cilia called comb rows
• have colloblasts, which are specialized adhesive cells for prey capture