Trophic Levels
Producers, Consumers, and Decomposers
Food Web Components
• Producer
(ex. plankton)
• Consumer
(ex. fish)
• Decomposer
(ex. bacteria)
Food Chain vs. Food Web
• Food Chain: path
of energy from
one organism to
the next
• Food Web:
interconnected
food chains
Producers
• A photosynthetic plant
(use sun) or chemosynthetic bacterium (use
chemical reactions)
• Constituting the first
trophic level in a food
chain
• An autotrophic organism
(can produce its own
food)
Producers
• Most producers use water, carbon dioxide, and
sunlight to produce food for themselves and oxygen
for other marine life.
Ocean Plants: Producers
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Producers make up the largest biomass of the ocean
Producers help sustain marine ecosystems by providing
oxygen and food for marine life
Includes: phytoplankton, diatoms, and dinoflagellates,
algal films, and seaweed
What is a Consumer?
• A heterotrophic
organism that ingests
other organisms or
organic matter in a food
chain.
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–
–
–
Herbivore
Carnivore
Omnivore
Detritivore
Consumers - Herbivores
• Animals that feeds
mainly on plants/plankton
Consumers - Carnivores
• Flesh eating animals.
Consumers - Omnivores
• Organisms that eats
both plants and animals
Consumers - Detritovores
• Organisms that feeds on
dead plant or animal
matter
Consumer Levels
Marine Primary Consumers
• Filter Feeders
• Grazers
• Browsers
Filter Feeders
• Eat diatoms
• Convert plant
material into animal
tissue
• Ex. Barnaclesextend feathers
into water
Grazers
• Eat algal films on rocks and surfaces
• Most grazers are classified as Molluscs
• Ex. Sea Slugs, Snails, Limpids
Browsers
• Eat algae
• Browsers are an important element of coral
reef ecology
Marine Secondary Consumers
• Cnidarians
• Comb Jellyfish
• Echinoderms
• Arthropods
• Molluscs
• Vertebrates
Cnidarians
• Great abundance in the
ocean
• Corals, Sea Jellies,
Anemones
• Have stinging tentacles
that stun prey and move
them into the gut of the
cnidarian
• Feed by predation
Comb Sea Jellies
• Classified as Ctenophora
• Hydroid in early stages of
life then grow to become a
free floater
• Use cilia for movement
• Tentacles are used for
capturing food
• Transparency helps with
protection - makes them
nearly invisible
Echinoderm
•
•
•
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Organisms with bilateral symmetry
Spiny skinned and have tube feet
Water Vascular System
Ex. Sea Stars, Sea Cucumbers, Sea Urchin
Arthropod
• Jointed legged
invertebrate
• Segmented body with
hard exoskeleton
• Eat by predation,
browsing seaweed,
scavengers
• Ex. crabs, shrimps,
sea spiders
Molluscs
•
•
•
•
Body without cavity, bilateral symmetry
Wide range of feeding (primary grazers)
Ex. Snails, Slugs, Squid, Bivalves
Largest Mollusc: Octopus
Vertebrates
•
•
•
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Internal skeleton, nerve chord, and backbone
Mostly predators
Largest predatory vertebrate: whale
Ex. dolphins, seals, sea turtles
Decomposers
• An organism, often a bacterium, that feeds on and
breaks down dead plant or animal matter, thus
making organic nutrients available to the ecosystem
• Puts nutrients back into the water in their
elemental form to be used by producers as
fertilizer
Review
• Producers (algae, sea weed, phytoplankton)
• Primary Consumers (grazers, browsers,
filter feeders) eat producers
• Secondary consumers eat primary
consumers
• Scavengers (ex. crabs) eat dead plants and
animals
• Decomposers (ex. bacteria and fungi) eat
the last bit of usable energy for organic
matter