Energy Flow in Ecosystems
All energy on Earth depends on the Sun All energy on Earth depends on the Sun. Organisms capable of using the sun’s energy directly are called Producers. Plants & Algae are Producers.
Producers make their own food; they are autotrophs. They do this through Photosynthesis: Water + Carbon Dioxide Glucose + Oxygen
Photosynthesis needs: Sunlight Water Carbon Dioxide And, inside plant cells: Chlorophyll Chloroplasts
These are the Consumers Producers support the animals that can’t make their own food – heterotrophs. These are the Consumers Animals that eat the producers are Primary 1o Consumers.
1o Consumers = Herbivores
In turn, they support the next level, the Tertiary 3o Consumer. These 1o Consumers are the food source for other heterotrophs, the Secondary 2o Consumers. In turn, they support the next level, the Tertiary 3o Consumer. These organisms can be carnivores or omnivores.
Carnivore or Omnivore?
There are some consumers which are only predators, and never prey. These are the Top Consumers, and they are usually strict carnivores, although some are omnivores.
Top Consumers
Whether an organism is a producer or consumer is part of defining its Trophic Level. Trophic Levels are categories of organisms based on how they get their energy.
If we link organisms by the rank of their Trophic Level, we get a Food Chain:
If we link several Food Chains, we get a Food Web:
If we link several Food Chains, we get a Food Web:
Food webs include specialist consumers, such as: Decomposers Scavengers Symbionts
With every step in a food chain, some energy is lost. This is often as body heat, so in a way, it’s not ‘lost’… it’s helpful But that energy can’t provide nutrition to others, so that way, it’s ‘lost’ Food Pyramids illustrate this
Food Pyramids
Food Pyramids measure T.E.
In any ecosystem, many producers support only a few top consumers.
Bioaccumulation or Biomagnification is a problem in ecosystems because of energy flow. Lower level consumers get amounts of a pollutant that is not toxic, but top consumers get very toxic effects.
Bioaccumulation: Arctic Food Chain
Bioaccumulation: Great Lakes Food Chain
Bioaccumulation: Bald Eagle & Peregrine Falcon