RELATIONSHIPS IN MARINE ECOSYSTEMS

Energy Flow• Sunlight – main energy source for life on

Earth.

• Goes through ecosystem in one direction, from sun or inorganic compounds, to autotrophs (producers), and then to various heterotrophs (consumers)

• Producers: autotrophs (plants, some algae, and certain bacteria) capture energy from sunlight or chemicals and make their own food

• Consumer- all heterotrophs: they rely on food containing the sun’s energy (producers)

Trophic Levels

• Each step in a food chain or web

• Producers are on the 1st trophic level and consumers are 2nd or higher levels. Each consumer depends on trophic level below it for energy.

Feeding Relationships• Food Chain: Simple model showing

the steps in which organisms transfer energy by eating and being eaten. Shows only one pathway of energy

• Food Web: All feeding relationships among various organisms in an ecosystem. Form a network of complex interactions and show all pathways of energy

• Predation – one organism captures and feeds on another organism. (predator/prey)• Predator – does the killing • Prey – one that is killed

FOOD WEBS

Type of relationship

Species harmed

Species

benefit

Species neutral

Mutualism

CommensalismParasitism

= 1 species

Symbiosis: Two species live closely together

Mutualism: Beneficial to Both species

• Examples:

• boxing crab and sea anemone

• cleaner shrimp

• lichens on rocks

Commensalism: One benefits and other is not helped nor harmed

• Examples: • Pilot fish and sharks

• Emperor shrimp and sea cucumber

• Polar bears and cyanobacteria

Parasitism: One organisms lives on or inside another and harms it

• Examples: • Lampreys/leaches

• isopods

• trematodes