section 2 science

sponges have little in common with other animals

most sponges are asymmetrical

sponges are sessile which means they attach to one surface and stay there

a sponge body is a hollow tube with and opening at the top and pores along the body

they often have spicuoles for protection

they eat and get oxygen from pores and wastes are removed from the opening at the top

most sponges are hermaphrodites that produce both sperm and eggs

some can reproduce by budding

cnidarians are invertebrates

most live in salt water

some live alone and some live in colonies

polyp is vase shaped and sessile

medusa is bell shaped and free swimming

cnidarians have one body opening and its radial symmetry

2 cell layers are arranged into tissues

a nerve net carries impulses and carries all the parts

most have tentacles with stringing cells to help capture food

cnidarians are predators

coral reefs and diverse ecosystems that protect shorelines from erosion

coral reefs supply resources such as shells, pearls, and chemicals for human medical uses