B17.2 Materials cycling Flashcards
What are decomposers?
Group of organisms such as bacteria which break down waste and dead animals/plants
What are the full steps of the decay cycle?
Decomposers return mineral ions including nitrates to the soil - plants take them up through their roots and used them to make proteins. Decay returns carbon to the atmosphere - carbon dioxide can be used in photosynthesis. Animals eat plants and eventually die then the cycle repeats
What are the main stages of the water cycle?
Water evaporates from the surface of the land and in lakes. It condenses as it rises into cooler air to form clouds. Where then it is precipitated onto the surface of the earth. Passes through animals and the earth. Percolation also happens ( water trickles through gaps in the soil and rocks). Then transpiration and respiration release water again and then it evaporates
Why is water important?
Water major constituent of all living cells,
chemical reactions of life (photosynthesis and respiration) take place in solution in water,
water needed by plants for support
Why is carbon and nitrogen needed?
Carbon is needed as carbon dioxide
for use by producers in photosynthesis.
Nitrogen is needed as nitrate ions
by plants to make proteins and other chemicals.
Carbon and nitrogen are taken up by animals through feeding relationships.
Carbon and nitrogen removed from the environment by plants need to be part of the decay cycle so that they can be recycled and used again by living organisms.
