• Mutualism - both benefit• Commensalism - one benefits• Parasitism- viruses, bacteria, flatworms,

leeches,

Symbiotic Relationships

Mutualistic relationships

• Zooxanthellae- in coral, anemones, snails, & giant clams

• Corals- crabs, shrimp, fish

• Sponges- nitrogen fixing cyanobacteria

• Anemone fish- anemone

• Obligate symbionts- committed, can’t live without

Relationships between anemone/fishes

Anemone fish Anemone

provide provide

1. Protection- drive 1. Safe place

away other fish 2. Nest/eggs

2. Sometimes will brooded under

feed host anemone

Pearl fish typically, they live inside clams, starfish or sea squirts, and are simply commensal, not harming their hosts. However, some species are known to be parasitic on sea cucumbers, living in their gut and eating their sex organs.

Commensal relationships

Parrot fish

• Are known for their parrot like beaks which they scrape algae from coral. This distributes coral sand, and prevents algae from choking coral. Can produce 90 Kg of sand a year. To keep up teeth grow continuously.

• Maneuver with pectoral fins.• Excrete mucus cocoon at night to hide scent. • Parrot fish must be protected to protect the

reef

Parrotfish

Damsel fish

• Brightly colored, territorial fish which include anemone fish some defend an area that grows a mat of algae, which they feed on. (garden of algae)

Hawaiian Domino Damselfish

Damselfish

Types of reef

• 1. Fringing Reefs

• 2. Barrier Reef

• 3. Atoll

Types of Reefs:

1. Fringing Reefs:

• Simplest kind

• Grow in narrow band/ fringe along shore

• Most vulnerable to pollution runoff

2. Barrier Reef:

• Farther from shore (up to 60 miles)

• Separated from shore by lagoon

• Sand islands form (sand cays)

• Spur and groove (buttresses) coral with sand channels - form in windward side.

• Great Barrier Reef/ Belize

3. Atolls:

• Ring of reef (or cays) surrounding lagoon

3. Atolls:

•Can be far from land and 1,000 meters deep

• Darwin solved the puzzle on how it formed fringing reef growth on a subsiding island (volcano).