6.1
what can be said about the flow of nutrients within an ecosystem?

6.1
describe the basic sequence of a nutrient cycle

6.1
give two reasons why the level of atmospheric CO2 has increased

6.1
explain how oceans act as a carbon sink

6.1
explain the role of saprobionts

6.1
how are organisms fossilised?

6.1
how are carbon-containing sedimentary rocks formed? give two examples of sedimentary rocks

6.2
what is the greenhouse effect? explain how it works

6.2
what is the most important greenhouse gas? why? why is it increasing?

6.2
how is methane produced?

6.2
what has the concentration of CO2 risen from?

6.2
what sort of changes has global warming brought about?

6.2
how does climate change affect a community of organisms?

6.2
explain five possible changes if global warming is to continue

6.3
what is nitrogen needed for?

6.3
explain ammonification

6.3
explain nitrification

6.3
explain nitrogen fixation

6.3
explain denitrification

6.4
what is the drawback of intensive food production?

6.4
what happens to the mineral ions in a natural ecosystem?

6.4
what happens to the mineral ions in an artificial ecosystem?

6.4
why is it important to replace mineral ions?

6.4
explain the two different types of fertiliser

6.4
briefly describe how the use of fertilisers increases productivity

6.5
explain how the use of nitrogen fertilisers may lead to reduced species diversity

6.5
explain how use of nitrogen fertilisers may lead to leaching. what are two possible consequences?

6.5
what is eutrophication? explain the process of eutrophication

6.5
what five other things may lead/contribute to eutrophication?