The Radiata

Question 0

What are the synapamorphies of Cnidaria?

Answer 0

Radially symmetrical
Diploblastic
Gastrovascular cavity with a single opening
Nerve nets

Question 1

What phyla are within this category?

Answer 1

Cnidaria

Ctenophora

Question 2

What are the three stages of the life cycle?

Answer 2

Sessile polyp stage
Free swimming medusa stage
Adult

Question 3

Describe the nervous system of Cnidaria

Answer 3

They have myofibrils which must be coordinated. The neurons monitor external stimuli which transmit that information as rapid depolarisation l. This exploits the potential of all cells to regulate ion concentrations.

Question 4

What are cnidocytes?

Answer 4

Combined sensory-effector cells, which contain large amounts of calcium ions. These get released into the cytoplasm when triggered. This creates a huge increase in osmotic pressure. They then release a penetrant, glunitant or volvent

Question 5

What are the three main classes of the Cnidaria?

Answer 5

Hydrozoa
Scyphozoa
Anthozoa

Question 6

What are the traits of the class Hydrozoa?

Answer 6

Usually stay as polyps

May be solitary or colonial

Question 7

What class do jellyfish fall into?

Answer 7

Scyphozoa

Question 8

What class does the Portuguese man of war fall into?

Answer 8

Hydrozoa

Question 9

What are the traits of Anthozoa?

Answer 9

Stay as polyps
May be solitary or colonial
Differ from hydrozoans in the gastrovascular cavity

Question 10

What is the key trait of phylum Ctenophora?

Answer 10

First phylum with a full gastrovascular cavity