B4.1.6 Nutrient Cycling

Question 1

What is nutrient cycling?

Answer 1

Materials passed between biotic and abiotic components of an ecosystem
Plants get their nutrients from the soil, leaves fall/plant decomposes, decomposers release nutrients back into soil, nutrients reabsorbed by plants

Question 2

Carbon’s uses

Answer 2

Used to make carbohydrates, fats, proteins, DNA
cycles between atmosphere, living organisms, fossil fuels
Can be trapped in oceans and rocks

Question 3

Nitrogen’s uses

Answer 3

Makes us 80% of atmosphere
Organisms use to make DNA and proteins
Most organisms can only use nitrogen as part of compound, like nitrate

Question 4

Nitrogen cycle

Answer 4

Nitrate dissolved in water existing in soil, taken up by roots, plant uses nitrates to create proteins, plant eaten, nitrogen compounds passed to animal, nitrogen released into soil as faeces and urea, plant/animal dies, compounds broken down and released into soil as ammonia
Some plants form mutualistic relationships w nitrogen-fixing bacteria: bacteria live in roots as combine nitrogen from air to oxygen making nitrates, used by plant

Question 5

Water cycle

Answer 5

Evaporation- sun heats Earth’s surface, liquid -> vapour
Condensation-water vapour rises in air, higher up=colder, gas-> liquid, producing clouds
Precipitation-water droplets in clouds get heavier and fall as rain
Percolation- water trickles through gaps in soils and rocks
Transpiration- loss of water vapour from plants directly into atmosphere