Topic 10.2 The efficiency of ecosystems

Question 1

Define gross primary productivity (GPP)

Answer 1

the rate at which light from the Sun catalyses the production of new plant material, measured as gm-2year-1, gCm-2 or KJm-2year-1 OR the rate at which energy is incorporated into biomass/organic matter by plants

Question 2

Define net primary productivity (NPP)

Answer 2

the material produced by photosynthesis stored as new plant body tissues, NPP=GPP-R

Question 3

Give an equation for NPP

Answer 3

NPP= GPP-R

Question 4

What is a trophic level?

Answer 4

describes the position of an organism in a food chain or web and describes its feeding relationship with other organisms

Question 5

Define producers

Answer 5

make food by photosynthesis or chemosynthesis

Question 6

Define primary consumers

Answer 6

organisms (mainly animals) that eat producers, either plants or algae- they’re herbivores

Question 7

Define secondary consumers

Answer 7

animals that feed on herbivores/primary consumers, carnivores

Question 8

Define tertiary consumers

Answer 8

animals that feed on secondary consumers, usually the top predators in an area

Question 9

Define decomposers

Answer 9

the final trophic level. they’re microorganisms e.g. bacteria or fungi that break down the remains of animals and plants and return mineral nutrients to the soil