Cnidarians - Jelly fish Flashcards
What are the 4 layers in the diploblastic cnidarian
Epidermis
Mesogeal
Gastrodermis
Gastrovascular cavity
How many openings does the cnidarian have
1
What are the 2 differences between the polyp stage and the medusa stage
The mesoglea is thicker and the gastrovascular cavity is reduced in the medusa stage
Symmetry, blastia and coelom
Radial + Diploblastic + Acoelomate
Where are cnidocytes and how do they work
On the tentacles of cnidarians
Contain nematocytes and cnidocils
When food is detected the cnidocil triggers the nematocyte which will evert and inject a toxin
Where does digestion occur in cnidarians
In the gastrodermal cells in the gastrovascular cavity
How do cniardians move
Gastrovascular cavity acts as a hydrostatic skeleton against which contractile cells can work
What do cniardians have instead of a brain
Non-centralised nervous net distributed radially
Where does fertilisation take place in cnidarians
Externally
Which is the asexual and sexual phase and what does each one produce
Sexual - Medusa producing gametes
Asexual - Polyp producing medusae
Give the stages of the cnidarian Obelia
- Fertilisation to form zygote
- Mitotic divisions to form planula larvae that develop into a mature polyp
- Budding forms a medusa bud
- Medusa bud forms into a adult medusa
Give 1 example for each of the 4 major classes of Cnidarians - Hydrozoan, Scyphozoan, Cubozoan and Anthozoan
H - Portuguese man-of-war
S - Sea nettles
C - Box jellies
A - Sea anemones - NOT medusozoan
What is the function of the statocysts
Organs of equilibrium that cause muscle contractions to right the Medusa
What is the function of the statocysts
Organs of equilibrium that cause muscle contractions to right the Medusa
