Food Chains & Food Webs Flashcards
Food Chain
Each food chain is a possible pathway that energy and nutrients can follow through the ecosystem. Shows sequence in which organisms are eaten, beginning with a plant, ending with an animal.The arrows on a food chain indicate where energy is being passed.
Trophic Levels
Organisms in food chains are grouped into categories called trophic levels. Roughly speaking, these levels are divided into producers (first trophic level), consumers (second, third, and fourth trophic levels), and decomposers.
Producers
Producers are autotrophs.
An autotroph is an organism that traps energy to produce its own food through photosynthesis.
E.g. Algae, along with plants and some bacteria and fungi, are autotrophs.
Primary Consumers
Herbivores; 1st order consumer; 2nd trophic level.
Feeds on plant material. Herbivores range in size from tiny insects such as aphids to large, lumbering elephants. Herbivores are a major part of the food web, a description of which organisms eat other organisms in the wild.
Deer, turtles, and many types of birds are herbivores.
Secondary Consumers
2nd order consumers, 3rd trophic level.
Secondary consumers are largely carnivores that feed on the primary consumers/herbivores. They are heterotrophs, carnivores or omnivores.
Tertiary Consumers
Carnivores; Third Order consumers; Fourth trophic level
Third-level consumers are any organisms big enough to obtain energy by feeding off lower-level consumers. The tertiary consumer is also referred to as the apex predator. Such consumers typically exist at the very top of every ecological food chain.
Detritivores and Decomposers
Detritivores are organisms that eat nonliving plant and animal remains. E.g. Dung beetles eat animal feces.
Decomposers like fungi and bacteria complete the food chain. They turn organic wastes, such as decaying plants, into inorganic materials, such as nutrient-rich soil. Decomposers complete the cycle of life, returning nutrients to the soil or oceans for use by autotrophs. This starts a whole new food chain.
Removal of organism from the food chain
If an organism is removed from the food chain, it spoils the flow of energy and nutrient in the ecosystem. It disrupts the balance of the food chain. As a result, the organisms which depend on others for food will die due to starvation.
Food Web
A food web consists of all the food chains in a single ecosystem. Each living thing is part of multiple food chains and a possible path that energy and nutrients may take as they move through the ecosystem. All of the interconnected and overlapping food chains in an ecosystem make up a food web.
What happens if an organisms is removed from a food web.
When one species disappears, its predators can no longer eat it and its prey are no longer eaten by it. Changes in these populations affect others. Such impact ‘cascades’ can be unpredictable and sometimes catastrophic. Will have ripple affects across a food web, where food chains are all interconnected.
