Unit 4.2: Energy Flow Flashcards
Define trophic levels.
A trophic level is an organism’s position in a food chain or web.
Explain how energy moves through a food chain.
Chemical energy in carbon flows through a food chain by being eaten by other organisms.
About how much energy is passed between trophic levels? How is this energy available?
Only about 10 - 20% of energy is passed between levels. The energy is only available if it is stored as chemical energy used in the growth of an organism.
How is energy lost between trophic levels?
Energy is lost in three ways:
1) Some organisms are not eaten.
2) Some parts of the animals are eaten but not digested (bones, hair, gristle), so they are lost in waste.
3) Much of what is eaten is used in cellular respiration and lost as heat.
What affect does the amount of energy that is transferred between trophic levels have on food chains?
The significant loss of energy that occurs between trophic levels restricts the length of food chains. The loss of biomass and energy that occurs means there is not enough energy at lower levels to support large numbers at the upper levels. Therefore there are fewer organisms at the top of the pyramid.
*Note; what are the trophic levels?
Be able to draw an accurate trophic pyramid, which does not look like a true pyramid. Instead, each level becomes thinner and thinner due to the significant loss in energy that occurs between tiers. It looks like a skyscraper with a wide base. Consists of primary producers, primary consumers, secondary consumers, tertiary consumers.
In what form does energy leave an ecosystem?
Energy leaves an ecosystem as heat. However, nutrients must be recycled through the carbon and nitrogen cycles.
