Sponges, Corals and Pre-bilaterian life Flashcards
1
Q
Which four taxa are basal to all metazoan
A
- Porifera (sponges)
- Placozoa
- Ctenophora
- Cnidaria
2
Q
Describe the body plan of Porifera.
A
- 2 cell layers
- pore cells
- choanocytes (flagellated feeding cells)
3
Q
What are the four main phyla of Cnidaria
A
- Scyphozoa (true jellyfish)
- Hydrozoa
- Anthozoa (sea anemones & coral)
- Cubozoa (Box Jellies)
4
Q
Describe the body plan of Cnidaria.
A
- Radial symmetry
- 2 cell layers
(epidermis and gastodermis) - single mouth/anus opening (able to close)
- Polyp or Medusa forms
(Polyp = tentacles up, Medusa = tentacles down)
5
Q
Describe the feeding of Cnidaria.
A
- Predatory
- Use of nematocysts
6
Q
Compare the feeding methods of the basal metazoans
A
Porifera → filter feed
Placozoa → Graze
Cnidaria → predators (stinging nematosysts)
Ctenophora → predators (sticky colloblasts)
7
Q
Compare the symmetry of the basal metazoans.
A
Porifera and placozoa have no symmetry
Cnidaria and ctenophora have ~radial symmetry
8
Q
Compare the nervous system of basal metazoans.
A
No centralised nervous system
Porifera and placozoa have no nerves
Cnidaria and ctenophora have a nerve network
