natural cycles and decomposition Flashcards
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boigas
definition
A type of biofuel (methane) derived from the action of bacteria on animal manure or other organic waste.
crop rotation
definition
When fields are used to grow the same crop in alternate years. This helps to maintain soil fertility.
decompose
definition
If a substance decomposes, it breaks down into simpler compounds or elements.
decomposer
definition
An organism which eats dead organisms, fallen leaves, animal droppings, etc, and breaks them down into simpler materials.
decomposition
definiton
The process of breaking down material to release nutrients back into the soil.
desalination
definition
The removal of salt from water. This is an energy-intensive process. Also known as desalinisation.
detrivores
definition
Animals that obtain nutrients by consuming detritus (decomposing plant and animal tissue as well as waste e.g. faeces).
distillation
definition
A separation technique which involves a solution being heated so that the solvent evaporates before being cooled to form a pure liquid.
drought
definiton
A long period of low rainfall that creates a major shortage of water.
eutrophication
definition
‘Hyper-nutrition’ resulting from fertiliser pollution of aquatic ecosystems.
indicator species
definiton
The presence, abundance or absence of these organisms provides information such as the level of pollution in the environment.
nitrate
defintion
The chemical absorbed from the soil by plants to produce their protein.
nitrifying bacteria
definition
The bacteria that produce nitrate which is released into soil.
nitrogen cycle
defintion
The sequence of events or processes involved in the recycling of nitrogen in the environment.
nitrogen-fixing bacteria
definition
The bacteria found free-living in the soil or in the root nodules of some plants such as peas and clover that convert nitrogen gas into nitrate.
potable
definiiton
Safe to drink.
water cycle
definition
The continuous movement of water on, above and below the Earth.
Peat bog
definition
Peat bogs are poorly drained areas made up of partially decomposed organic matter due to waterlogging.
How materials are cycled in an ecosystem
atoms
Carbon and water
Atoms exist in different forms or compounds at different times in history and cycle between them. This cycling can be seen in the element carbon and the compound water.
How materials are cycled in an ecosystem
Living organisms
Other elements and compounds also exist in cycles. Elements pass along food chains when animals eat plants and other animals. Many humans eat protein in the form of meat from other animals. The body breaks this down into amino acids and then uses these to make proteins within the body for growth and repair. When someone dies these building blocks are returned to the environment to be used by other living organisms.
How materials are cycled in an ecosystem
Decomposing bacteria and fungi
Decomposing bacteria and fungi break down dead organisms. They help recycle minerals and nutrients to the environment, which can then be used by other organisms. As they decompose dead matter, the decomposers also respire and so release carbon dioxide to the environment, contributing to the carbon cycle.
How materials are cycled in an ecosystem
biotic and abiotic
Materials cycle through both the non-living abiotic and living biotic factors within the ecosystem.
What is the carbon cycle?
Carbon is passed from the atmosphere, as carbon dioxide, to living things, passed from one organism to the next in complex molecules, and returned to the atmosphere as carbon dioxide again. This is known as the carbon cycle.
The carbon cycle shows how atoms of this element can exist within different compounds at different times.
Which cells contain carbon?
All cells - whether animal, plant or bacteria - contain carbon, because they all contain proteins, fats and carbohydrates. Plant cell walls, for example, are made of cellulose - a carbohydrate.
Importance of carbon
Carbon is an essential element for life on Earth and parts of each of the cells in our bodies are made from it. The carbon cycle shows how atoms of this element can exist within different compounds at different times.
Removing carbon dioxide from the atmosphere
Green plants remove carbon dioxide from the atmosphere by photosynthesis. The carbon becomes part of complex molecules such as proteins, fats and carbohydrates in the plants.
Returning carbon dioxide to the atmosphere
Organisms return carbon dioxide to the atmosphere by respiration. It is not just animals that respire. Plants and microorganisms do, too. Carbon dioxide is also released by combustion. The burning of fossil fuels releases large quantities into the atmosphere.
Passing carbon from one organism to the next
When an animal eats a plant, carbon from the plant becomes part of the fats and proteins in the animal. Decomposers and some animals, called detrivores, feed on waste material from animals, and the remains of dead animals and plants. The carbon then becomes part of these organisms.
Stage one of the carbon cycle
Carbon enters the atmosphere as carbon dioxide from respiration and combustion.
Stage two of the carbon cycle
Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis.
Stage three of the carbon cycle
Animals feed on plants, passing the carbon compounds along the food chain. Most carbon they consume is exhaled as carbon dioxide during respiration. The animals and plants eventually die.
Stage four of the carbon cycle
Dead organisms are eaten by decomposers and carbon in their bodies is returned to the atmosphere as carbon dioxide. In some conditions decomposition is blocked. The plant and animal material may then be available as fossil fuel in the future for combustion.