Marine Biology

Invertebrates Slides:

What are Animals?

• animals are multicellular.

• Animal cells are eukaryotic and lack cell walls

• animals cannot produce their own food

• Animals can actively move

Invertebrates: animals that lack a backbone

Vertebrates: animals that have a backbone.

Sponges: simple, asymmetrical, sessile animals

Sessile: permanent attatched to a solid surface.

Ostia: holes in the body of sponges through which water enters.

Spongocoel: cavity in the body of a sponge.

Osculum: opening through which a sponge expels water

Tissues: groups of specialized cells that preform a specific function.

Collar cells: flagellated cells in a sponge that circulates water and traps food.

Pinacocytes: cells that make up the outer covering of a sponge and the line the internal chambers not lined by choanocytes.