1. Today…
Bellringer: Are animals autotrophs or heterotrophs? Explain your answer.
Review Section 1 – What is an animal?
Notes on Sponges and Cnidarians

2. Sponges
-and-
Cnidarians
Science 6

3. Today’s Goal…
I can describe the characteristics of sponges and cnidarians.

4. 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

5. 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

6. 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

7. 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

8. Sponges
Let’s see more about sponges!

9. 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

10. 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

11. Cnidarians Produce sexually and asexually Figure 6
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

12. Cnidarians
Learn more about Cnidarians!

13. Real Pics
Sponges

14. Real Pics
Cnidarians