9.12, 9.13, 9.14 - Cycling of Materials, The Carbon Cycle, The Water Cycle Flashcards
What are the vital cycles for life on Earth?
The carbon and water cycles.
How is CO₂ removed from the air in the carbon cycle?
CO2 is removed by green plants and algae during photosynthesis.
What do plants and algae use carbon for?
They use carbon to make carbohydrates, proteins, and fats.
How is CO₂ returned to the air?
CO2 is returned when plants, algae, and animals respire.
What role do decomposers play in the carbon cycle?
Decomposers respire while breaking down dead organisms and waste, returning mineral ions to the soil.
What is combustion in the context of the carbon cycle?
Combustion is the burning of wood and fossil fuels, returning CO2 to the air.
What is compost?
Compost is produced when biological material decays and is used as a natural fertilizer.
What conditions are needed for optimal decay in composting?
Optimum conditions include sufficient oxygen for aerobic respiration, which produces heat.
What is produced when microorganisms decompose waste anaerobically?
Methane gas.
How can methane gas be used?
Methane can be burnt as a fuel.
What are biogas generators used for?
Biogas generators produce methane and require a constant temperature of 30 degrees.
What causes water to evaporate in the water cycle?
The sun’s energy causes water to evaporate from seas and lakes.
What is transpiration in plants?
Transpiration is the process that forms water vapour as water is released from plants.
What happens to water vapour in the water cycle?
Water vapour rises, condenses to form clouds, and is returned to the land by precipitation.
What is precipitation?
Precipitation includes rain, snow, or hail that returns water to the land.
How can we produce potable water in drought areas?
We can harness the water cycle, for example, through desalination.
What is desalination?
Desalination is the process of removing salt and other impurities from water.
What causes water to evaporate from the sea and lakes?
The sun’s energy causes water to evaporate from the sea and lakes, forming water vapour.
How is water vapour formed in plants?
Water vapour is also formed as a result of transpiration in plants.
What happens to water vapour in the atmosphere?
Water vapour rises and then condenses to form clouds.
How is water returned to the land?
Water is returned to the land by precipitation (rain, snow or hail).
What happens to precipitation after it falls?
It runs into lakes to provide water for plants and animals.
What is the process that begins the water cycle again?
This then runs into seas and the cycle begins again.
How can we harness the water cycle in areas of drought?
We can harness the water cycle to produce potable (drinkable) water.
