Corals and Hydroids

1. Corals and Hydroids Chapter 7.3 and 7.4

2. Coral Reefs • Very large structures made from very tiny animals (some are microscopic). • Reefs are named after familiar objects whose shape they resemble: • Hard corals include: elk horn coral, staghorn coral, brain corals • Soft corals include: fan coral, sea whip coral, sea plume coral and sea rod coral

3. Elk Horn Coral

4. Stag Horn Coral

5. Brain Coral

6. Fan Coral

7. Sea Whip Coral

8. Sea Plume Coral

9. Sea Rod Coral

10. Coral Polyp • Life activities like ingestion, digestion, sensitivity, exchange of gases, and reproduction are similar to anemones • Coral polyps are colonial and connected by a membrane (colonial stomach) that allows them to share food

11. Structure of the Polyp • Tiny mound of tissue that sits in a cup-shaped depression that forms in the surface of the reef. • Adds layer after layer of limestone to the reef year after year which adds to the coral reef

12. Symbiosis • Polyp needs tons of energy to build the reef, so it relies on a symbiotic relationship with an algae called zooxanthellae. • Polyp feeds with tentacles and take energy from the algae while giving it a place to live

13. Coral Reef • The reef is made of limestone (CaCO3). The polyps get the ingredients for limestone from the seawater. • Live in tropical water. Needs water to be clear for photosynthesis.

14. Hydroids • Class Hydrozoa • Also colonial and look plantlike • Different members of the colony perform different functions: • Feeding polyp, reproductive polyp, floatation polyp, etc.

15. Hydroid Members Portuguese Man O’War Obelia