Food Chains and Food Webs Energy Flow in

Food Chains and Food Webs Energy Flow in Nature

Energy Roles • An organism’s energy role in an ecosystem may be that of a producer, consumer, or decomposer.

Producers • An organism that can make its own food is a producer. • Autotroph • Source of all food in an ecosystem. • Capture energy from sunlight and stores it as food energy.

Consumers • Consumers are heterotrophs, or living things that cannot make food for themselves. • A food chain contains several kinds of consumers, each of which occupies a different trophic level. • Herbivore, carnivores, omnivores

Niche-A niche is an organism’s way of making a living that includes choices of habitat, food and behavior. No two species within a community may share the same niche. This eliminates competition.

Example of Ecological Niche: basically how an animal/plant lives day to day. • • Oak Tree: Oak trees: absorb sunlight by photosynthesis; absorb water and mineral salts from the soil; provide shelter for many animals and other plants; act as a support for creeping plants; serve as a source of food for animals; cover the ground with their dead leaves in the autumn.

Hedgehogs • Hedgehogs in a garden also have an ecological niche. They rummage about in the flowerbeds eating a variety of insects and other invertebrates which live underneath the dead leaves and twigs in the flowerbeds. That is their profession. • They are covered in sharp spines which protect them from predators, so being caught and eaten is not a part of their job description. • However, hedgehogs cannot groom themselves properly. All those spines on their backs make a superb environment or microhabitat for fleas and ticks. • Hedgehogs put nitrogen back into the soil when they urinate! • They eat slugs, so that reduces the effect which slugs have on the flowers.

Consumer Tropic Levels • Primary consumers eat producers (herbivores) • Secondary consumers eat primary consumers (carnivores) • Tertiary consumers eat secondary consumers (carnivores) • Scavengers are carnivores that feed on the bodies of dead organisms.

Decomposers • Help break down wastes and dead organisms and return the raw materials to the environment • Bacteria and fungi

Food Chains • Series of events where one organism eats another and obtains energy. • First organism in chain is the producer. • The second organism is the consumer that eats the 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 in an ecosystem. • Some organisms may play more than one role by changing consumer levels.

What happens in a food web if one or more of the organisms disappear?

Which animals are carnivores and herbivores?

Energy Pyramids • A diagram that shows the amount of energy that moves from one feeding level to another in a food web. • Represented in a triangle with the most energy at the producer level.

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.

Energy Pyramid