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2. Porifera and cnidaria. - Coggle Diagram
2. Porifera and cnidaria.
Common characteristics:
No organs.
Live in aquatic ecosystems.
Simplest groups.
Porifera
Habitat and nutrition
Some live in freshwater.
As adults, are sessile and live attached to rocks or coral.
Marine.
Filter feeders (feed on small particles of nutrients suspended in water)
Body
Sac - shaped.
Skeleton made up of...
Soft, flexible
fibres
.
A combination of both.
Hard
spicules
or
spikes
No
symmetry
.
Consist of sponges
Water enters through the
central cavity
.
Deposits nutrients, and leaves through an opening called the
osculum
.
Filter feeders
Body wall full of
pores
and channels.
Cnidarians
Habitat and nutrition
Jellyfish float.
Corals and sea anemones live attached to the ocean floor.
Often lives in colonies.
Carnivorous predators.
Most live in the ocean.
Body
Soft.
One opening surrounded by
tentacles
with stinging cells to paralyse prey.
Radial symmetry
.
Gastrovascular cavity
(stomach), connected to the mouth.
They have cnidoblasts, stinging cells, that give the group its name.
Three groups
Corals.
Sea anemones.
Jellyfish.
Two stages
Polyp stage
Hard skeleton of calcium carbonate.
Over time, skeletons form coral reefs.
Sac - shaped.
Medusa stage
Opening bottom.
Move by contracting their bodies or being pushed by ocean currents.
Umbrella - shaped.
