Sponges, Cnidarians, Flatworms, & Roundworms Chapter 6 Section 2
Sponges • Fun Fact: For a long time, scientists thought sponges were plants, not animals. • Adult sponges are sessile- remain attached to one place
Sponges- Filter Feeders • Most sponges live in oceans, but some live in freshwater. • Filter food out of water that flows through body • Microscopic organisms and oxygen are carried into central cavity through pores of sponge • Flagella keep water moving though sponge
Sponges- Body Support & Defense • Soft bodies supported by sharp, glasslike structures called spicules • Some have material called spongin- similar to foam rubber, making bodies elastic and soft • Some have both.
Cnidarians • Have tentacles surrounding mouth (ex. Jellyfish, coral, sea anemones) • Tentacles shoot out stinging cells, called, nematocysts, to catch prey • Have radial symmetry, can locate food that floats by from any direction
Cnidarians- Body Forms • 2 different body forms • Vase-shaped called polyp • bell-shaped body called medusa
Flatworms • Search for food • Invertebrates with long, flattened bodies • Bilateral symmetry • Soft bodies with 3 layers of tissue • Plnaraians- free-living flatworms with digestive system with one opening • Parasites- live in or on their hosts
Roundworms • Most widespread animal on Earth • Body like a tube within a tube, with a fluid-filled cavity between two tubes • Digestive tract has two openings • Some are decomposers, some predators
Exit Ticket • Pick one question and answer in a complete sentence. • Why would spongin and spicules discourage predators from eating sponges? • What are three characteristics of flatworms and roundworms.