Food Chains and Food Webs Energy Flow in
Food Chains and Food Webs: Energy Flow in Nature
The source of energy in EVERY ecosystem= THE SUN!
Trophic Levels • The number of steps from the start of a food chain. • -troph=“nutrient”
Producers • makes its own food energy from sunlight is a producer. (Photosynthesis) • Also called Autotrophs (self feeders) • Source of all food in an ecosystem.
Consumers • Consumers are heterotrophs. They must eat things to get energy. • Herbivore, carnivores, omnivores
Consumer Trophic Levels • Primary (1°) consumers eat producers (herbivores) • Secondary (2°) consumers eat primary consumers (carnivores) • Tertiary (3°) consumers eat secondary consumers (carnivores) • Scavengers are carnivores that feed on the bodies of dead organisms. • Omnivores eat plants and animals
Decomposers • Break down wastes and dead organisms and return the raw materials to SOIL • Bacteria and fungi and scavengers
Food Chains • Series of events where one organism eats another and obtains energy. • First organism in chain is always a producer.
Plankton Crab Seal Orca This is only one possible chain in a marine ecosystem.
Come up with an example to fill in the blocks of a food chain in two different ecosytems.
Food Webs • Consists of many overlapping food chains • Some organisms may play more than one role by changing trophic levels.
What happens in a food web if one or more of the organisms disappear?
Energy Pyramid • A diagram that shows the amount of energy that moves from one feeding level to another in a food web. • Most energy at the producer level. (bottom)
Energy Loss and Use • 10% of energy transferred to next higher level. • 90% of energy is used by organisms’ life processes. • Due to energy loss, ecosystem cannot support many feeding levels. • Number of organisms at each level gets MUCH smalller
Biological Magnification. Pollutants become MORE concentrated as they move up the food chain. (example- why eagles have thin egg shells and shark meat can be unsafe to eat)
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