Question

food webs & energy pyramids

1. what does an energy pyramid represent?
2. how much energy is available to the next step of the pyramid?
3. what happens to the energy that is lost? where does it go?
4. in every ecosystem, the energy originally comes from where?
5. using the food web on the previous page, fill in the energy pyramid.
6. why do tertiary consumers have smaller populations than producers or primary consumers?
7. what would happen to this ecosystem if there were a new primary consumer introduced? how would the populations of the other species be affected?

Explanation:

1. An energy pyramid represents the flow of energy through different trophic levels in an ecosystem, with the amount of available energy decreasing as you move up the levels.
2. Typically, only about 10% of the energy from one trophic - level is available to the next step of the pyramid. This is known as the 10% rule.
3. The energy that is lost is dissipated as heat during metabolic processes such as respiration in organisms.
4. In every ecosystem, the energy originally comes from the sun. Producers (like plants) capture solar energy through photosynthesis.
5. Without the food - web details from the previous page, we can't fill in specific energy values, but generally, the producer level (grass/plant) has the most energy, followed by the primary consumer (rabbit), then the secondary consumer (snake), and the tertiary consumer (eagle) has the least energy.
6. Tertiary consumers have smaller populations than producers or primary consumers because there is less energy available at higher trophic levels. A large amount of energy is lost at each transfer, so there isn't enough energy to support a large number of top - level consumers.
7. If a new primary consumer is introduced, it may compete with the existing primary consumer (rabbit) for resources (grass/plants). This could lead to a decrease in the population of the existing primary consumer. It may also affect the populations of secondary and tertiary consumers. If the new primary consumer is prey for the secondary consumer, the secondary consumer population may increase. If the new primary consumer out - competes the existing one, the secondary and tertiary consumers may be negatively affected due to a decrease in their food source.

Answer:

1. The flow of energy through trophic levels with decreasing available energy up the levels.
2. About 10% of the energy from the previous level.
3. Dissipated as heat during metabolic processes.
4. The sun.
5. Producer level has most energy, tertiary consumer level has least (specific values depend on food - web).
6. Less energy available at higher trophic levels.
7. May compete with existing primary consumer, affecting populations of other species depending on predator - prey relationships.