Basal Animal Phyla

Quiz 2

characteristic of a sponge

Monoecious, Often has central cavity, Filter Feeders, Diffusion as main gas exchange

The following are statements regarding poriferans. Which of the following are correctly described? Select all that apply. (Wrong selection will incur deductions)

Demospongiae have siliceous spicules.

Hydrozoan

Medusa has a velum

Cubozoan

Has rhopalia in eyes

Staurozoan

True Jellyfish

Anthozoan

Sea anemones, corals, sea pens

Choanocyte

flagellated cells having collar like ring in microvilli along flagellum

Oscula

single external opening of the sponge

Spongocoel

also called paragaster; central cavity of sponges

Pinacocyte

thin flat cells of the pinacoderm

Mesohyl

collagenous substance under pinacoderm providing supportive matrix

Luecon

dermal pore - incurrent pathways - flagellated choanocytes - excurrent canals - spongocoel - osculum

Ascon

ostia - choanocytes - spongocoel - osculum

Sycon

ostia - incurrent canal - radial pathway - spongocoel - osculum

In cnidarians, the stationary phase is referred to as

POLYP

In cnidarians, the moving ones are deems as

MEDUSAS

Spirocyst

Used to coil and stick around prey or objects.

Ptychocyst

Used to cover itself from predators

Nematocyst

Used to penetrate and inject venom into prey or predators

Cnidarians

Anthozoans possess a primitive nervous system. Cubozoans exhibit diplobasticity