Food Chain, Ecological Relationships

food chain

feeding relationship between the different organisms that make up our ecosystem

primary producers

capable of producing their own food from such substance as carbon dioxide and turning it into energy with the help of sunlight

• plants and algae

primary consumers

those who feed on the first trophic level, the autotroph biomass, from the second trophic level

secondary consumers

animals that eat herbivores (an organism that mostly feeds on plants)

• snake eating rabbits

tertiary consumers

carnivores that consume other carnivores

• e.g., killer whales hunt seals and lions

• kill fish, squid, and octopus

quaternary consumers

typically carnivorous animals that eat tertiary consumers

• aka apex predator or alpha predator or apical predator

• predators residing at the top of the food chain upon which no other creatures prey

decomposers

break down dead plants and animals

• break down the waste of other organisms

• keep up continuous flow of nutrients for the primary producers

mutualism

• Both organisms are benefitted

• Exhibits positive-positive relationship

commensalism

• One organism is benefitted while other is unaffected or unharmed

• Positive-neutral

parasitism

• One is benefitted, one is affected and harmed

• Positive-negative

• Benefiter: parasite (usually smaller)

predation

• One organism is benefitted, one is killed and eaten

• Predator: benefits

• Prey: killed and eaten 

competition

• Organisms compete for limited resources (e.g., space, food)

• Both are harmed or affected negatively

• Negative-negative