module 6: recycling in ecosystems

Question 1

stages in the carbon cycle

Answer 1

1- carbon absorbed by plants in photosynthesis
2-carbon passed on to primary consumers when they eat plants and passed to secondary consumers etc
3- organisms die and carbon compounds in dead organisms digested by microorganisms called decomposers
4-carbon returned to air in respiration
5- if dead organic matter not surrounded by decomposers they turn into fossil fuels which releases carbon if burnt- combustion
6- rocks can be made form dead organic matter
7- movement of tectonic plates can release carbon e.g. volcanoes
8- chemical weathering causes ions to be related from ground and rocks which mix with rivers and oceans to form carbon compounds
9- co2 can dissolve into oceans from the atmosphere

Question 2

overview of carbon cycle

Answer 2

1- carbon absorbed by plants
2- passed to consumers
3- carbon digested by decomposers
4- carbon returned to air-repsiartion
5- carbon in fossil fuels released when burnt
6- dead organic matter form rocks
7- rocks weathered chemically and release ions, form c compounds with oceans
8- co2 can dissolve into oceans and transported in deep currents

Question 3

what are the 4 main stages of the nitrogen cycle

Answer 3

1-nitrogen fixation
2-ammonification
3-nitrification
4-deintrification

Question 4

what is nitrogen fixation

Answer 4

nitrogen gas in the atmosphere is turned into ammonia by bacteria such as rhizobium in root nodules and azotobacter in soil

Question 5

what is ammonification

Answer 5

nitrogen compounds from dead organisms turned into ammonia by decomposers which goes onto form ammonium ions

Question 6

what is nitrification

Answer 6

ammonium ions in soil changed into nitrogen compounds that can be used by plants
nitrifying batter nitrosomonas change the ions to nitrates
nitrobater change nitrites into nitrates

Question 7

denitrification

Answer 7

nitrates in soil covered into nitrogen gas by denitrifying bacteria that anaerobically respire to produce nitrogen gas

Question 8

why do we need the nitrogen cycle

Answer 8

converts nitrogen into a useable form and passed between living organisms
plants need nitrogen to make proteins and nucleic acid