1. Animals that Eat Live Organisms
2. Carnivores
3. Herbivores
4. Animals that Eat Dead Organisms
5. Scavengers
6. Detritivores

Predators

1. Predators are animals which capture, kill and consume other organisms which are called prey.
2. The prey organism can be of any type. Predators are classified by the type of prey they consume.

Carnivores

1. Predators that eat other animals are called carnivores.

Herbivores

1. Predators that eat plants, seaweeds and algae are called herbivores.

Types of Carnivores

1. Carnivores are classified by the way they capture prey.
2. There are four types of carnivores: attackers, ambushers, filter feeders, and grazers.

Attackers

1. Pursuing carnivores that "run down" their prey.
2. They are highly active with acute senses.
3. Ex: Barracuda are rapid swimmers with long jaws and large teeth.

Ambushers

1. Remain in one place and wait for prey to come to them.
2. They must remain perfectly still and are often camlouflaged so that prey animals will not see them until it is to late.

Types Ambushers

1. Some rush out of hiding to grab their prey.
2. Some lure their prey to them.
3. Some are attached to the bottom and their prey must blunder into them.

Sit-and-wait Ambushers

1. Accelerate quickly and have large or specialized mouths to dispatch prey quickly.
2. Ex: Trumpetfish hide among soft corals, dart out and slurp up prey with their long tubular snouts.

Anglers

1. Have a modified body part that mimics the food of their prey luring them close to a large upturned mouth.
2. Ex: Frogfish perch on the bottom and lure prey by wiggling a modified dorsal spine.

Attached Ambushers

1. Slow to move and lack sense organs.
2. Ex: Sea Anemones creep slowly along on their pedal discs & eat prey that swim or crawl into them unsuspectingly.

Filter Feeding Carnivores

1. Filter Feeding carnivores are capable of processing large quantities of water.
2. Eat zooplankton & small fish.
3. Ex: Baleen Whales scoop up zooplankton & filter them with their baleen.

Grazing Carnivores

1. Grazing carnivores consume prey that cannot escape.
2. Eat animal colonys or portions of colonies.
3. Ex: Nudibranchs tear off portions of hydroid colonies with their radulas.

Types of Herbivores

1. Herbivores are classified by the size of the plant-like prey they eat.
2. There are two types of herbivores: macrophagous and microphagous.

Macrophagous Herbivores

1. Macrophagous herbivores eat large plants and seaweeds.
2. Some scrape off small portions.
3. Some chew off large chunks or consume the whole prey item.

Kelp Eating Urchins

1. Sea Urchins will grab pieces of detached kelp that drift by.
2. They can also attack standing kelp chewing through the stipes and detaching whole portions.
3. The devour the kelp with their five jawed Aristotle's lantern.

Microphagous Herbivores

1. Microphagous herbivores eat small algae and seaweeds which they must gather in large numbers.
2. Some are grazers that scrape algal films from surfaces.
3. Some are filter feeders that filter it out of the water.

Grazing Herbivores

1. Limpets use their radulas to scrape low growing algal turfs (about 1mm in height) from the surfaces of rocks.
2. The limpets leave behind what appears to be bare rock but the turf can regrow to be grazed again.

Filter Feeding Herbivores

1. Acorn Barnacles collect their food by filtering it out of the water using their cirri (legs).
2. Mussels collect their food by filtering it out of the water using their gills.

Legs as Filters

1. Barnacle cirri are held together in the shape of a basket as they are swept through the water.
2. Algal cells are captured on the cirri and are transferred to the mouth at the base of the basket.

Gills as a Pump

1. The mussel pumps water by the beating of many tiny, hair-like cilia on the gills and the thin, fleshy mantle that lines the shell.
2. The water enters the shell cavity, passes through the gills and then exits.

Gills as a Filter

1. Algae is filtered from the water by the mussel gill and is conducted by cilia along the gill toward the mouth.
2. At the top of the gill a set of small labial palps pass the food from the gill to the mouth.

Saprophages

1. Saprophages are organisms which consume dead and decaying organic matter.
2. The source of the organic matter is the bodies or parts of previously living organisms.

Types of Saprophages

1. Saprophages are classified by the types of organic matter they consume.
2. There are two types of saprophages: scavengers and detritivores,

Scavengers

1. Scavengers are animals that eat the corpses of animals or plants.
2. They are active animals with acute senses.
3. To find the rare corpse a scavenger must search over relatively large areas and detect their food from a distance.
4. They must locate their food quickly before other scavengers beat them to it.

Isopod Scavengers

1. Isopods are small crustaceans that are excellent swimmers and walkers.
2. They have compound eyes and sensitive antennae.
3. They can be found swarming on and devouring dead plant or animal tissues.

Detritivores

1. Detritivores are animals that eat organic fragments called detritus.
2. Detritus is formed when dead plants and animals are broken down into tiny bits.

Detritus

1. Detrital particles are covered with bacteria which are often the most nutritous part of the particles.
2. Detrital particles are often mixed with sediments and must be collected by the detritivore.

Types of Detritivores

1. Detritivores are classified by the way they gather detrital particles.
2. There are two types of detritivores: deposit feeders and suspension feeders.

Deposit Feeders

1. Many deposit feeders swallow sediments, digest the organics and pass the undigestible sediment as feces.
2. Some deposit feeders are more descriminating, selecting and swallowing edible particles only.

Selective Deposit Feeders

1. Selective deposit feeders pick the detritus out of the sediments and eat it.
2. Ex: Spagetti Worms have many long tentacles that convey detrital particles to the mouth. Particles of sediment are rejected prior to swallowing.

Suspension Feeders

1. Suspension feeders filter suspended detritus out of the water.
2. They operate in much the same way as predatory filter feeders.
3. Ex: Fan Worms have feathery tentacles that produce a current. Detritus filtered by the tentacles is conducted to the mouth.