Transcript Sponges
Today… • Bellringer: Are animals autotrophs or heterotrophs? Explain your answer. • Review Section 1 – What is an animal? • Notes on Sponges and Cnidarians Science 6 Today’s Goal… • I can describe the characteristics of sponges and cnidarians. Sponges • Plant or animal? • Adult sponges are sessile – remain attached to one place • Sponges can’t make their own food • About 15,000 species of sponges identified Sponges • Most live in oceans, some in freshwater • Bodies made up of two layers of cells • Filter feeders – Filter food out of the water that flows through their body Sponges • Not many animals eat sponges • Their soft bodies are supported by sharp, glass-like structures called spicules • Other sponges have a material called spongin which is similar to foam rubber and makes them soft and flexible • Some have both Sponges • Reproduction – Asexually and sexually – Asexual through budding • A bud on the side of a parent sponge develops into a small sponge or a new sponge grows from pieces of a broken sponge – One sponge can produce both egg and sperm for sexual reproduction – Figure 5 on page 502 Sponges • Let’s see more about sponges! Cnidarians • Jellyfish, sea anemones, hydra, and corals • Have tentacles surrounding their mouth – Tentacles shoot out stinging cells called nematocysts to capture prey • Radial symmetry allows them to locate food in any direction Cnidarians • Hollow bodied animals with cells that are organized into tissues • Two different body forms – – – – Polyp – vase shaped body (sea anemone and hydra) Medusa – free-swimming, bell-shaped body (jellyfish) Some have both these forms Page 503 Cnidarians • Produce sexually and asexually – Polyps reproduce asexually by budding – Some polyps reproduce sexually by releasing egg or sperm into water – Medusa reproduce sexually to produce polyps, then polyps reproduce asexually to form medusa • Figure 6 Cnidarians • Learn more about Cnidarians! Real Pics • Sponges Real Pics • Cnidarians