Energy Flow (4.2)

Question 1

Long Answer (Photosynthesis/Trophic Levels)

Answer 1

Plants absorb light from the sun and undergo photosynthesis, converting this light energy into chemical potential energy. Part of this light energy is also used to make organic compounds from inorganic sources. Consumers feed on these plants to obtain their chemical potential energy, (in other words they use autotrophs as a source of energy).

Question 2

What is the initial energy source for almost all communities?

Answer 2

Light.

Question 3

Biomass

Answer 3

Biomass is the total mass of a group of organisms – consisting of the carbon compounds contained in the cells and tissues. Because carbon compounds store energy, scientists can measure the amount of energy added to organisms as biomass.

Question 4

Food Chains

Answer 4

The transfer of the sun’s energy from producers to consumers as organisms feed on one another.

Question 5

Trophic Level

Answer 5

The position that an organism occupies in a food chain - what it eats, and what eats it.

Question 6

Food Webs

Answer 6

The interconnected pattern of food chains in a community.

Question 7

Pyramids of Energy

Answer 7

A graphical representation of the amount of energy at each trophic level of a food chain. Expressed in energy per unit area per unit time eg. kJ/m²/year

Question 8

Pyramid of Numbers

Answer 8

A pyramid of numbers shows the relative number of organisms at each trophic level in a food chain. However, they are not often useful, pyramids of biomass/energy give a more informative idea of the ecosystem interactions.

Question 9

Position of organisms in Trophic Levels

Answer 9

Producer -> Primary Consumer -> Secondary Consumer
-> Tertiary Consumer

Question 10

How much energy is generally passed between trophic levels?

Answer 10

Approximately 10%