Nutrient Cycling

EVM Nutrient Cycling 

•A nutrient cycle (or ecological recycling) is the movement and exchange of organic and inorganic matter back into the production of living matter.

•A nutrient cycle (or ecological recycling) is the movement and exchange of organic and inorganic matter back into the production of living matter.


•The process is regulated by food web pathways that decompose matter into mineral nutrients.


Carbon cycle-
•Most of the chemicals that make up living tissue contain carbon. When organisms die the carbon is recycled so that it can be used by future generations. The model that describes the processes involved is called the carbon cycle.


Nitrogen cycle-
•Nitrogen is essential for the formation of amino acids in proteins.
•There's lot of nitrogen in air – about 78 percent of the air is nitrogen.
•Because nitrogen is so unreactive, it cannot be used directly by plants to make protein.
•Only nitrates are useful to plants,
•so we are dependent on other processes to convert nitrogen to nitrates in the soil.

Steps in Nitrogen Cycle
•Nitrogen gas is converted to nitrate compounds by nitrogen-fixing bacteria in soil or root nodules. Lightning also converts nitrogen gas to nitrate compounds. The Haber process converts nitrogen gas into ammonia used in fertilizers. Ammonia is converted to nitrates by nitrifying bacteria in the soil.
•Plants absorb nitrates from the soil and use these to build up proteins. The plant may be eaten by an animal, and its biomass used to produce animal protein.
•Urea and egested material is broken down by decomposers. This results in nitrogen being returned to the soil as ammonia.
•Decomposers also break down the bodies of dead organisms resulting in nitrogen being returned to the soil as ammonia.
•In some conditions denitrifying bacteria in the soil break down nitrates and return nitrogen to the air. This is usually in waterlogged soil. Improving drainage reduces this effect, making the soil more fertile.




RESOURCE POTENTIAL OF BIOMES

Is the total weight of all organisms in a population, community or habitat.
Pyramids
The width of the horizontal bands is proportional to the masses at each level. The pyramid shape is always produced because one trophic level can only support a smaller biomass above it because of E losses at each level.
Size
Is a reflection of the productivity of the ecosystem. The productivity
is the range at which E is absorbed by plants.
Net primary productivity:
the growth rate of vegetation measured by the increase in the biomass over 4 years.
Greatest productivity:
when all the requirements for growth, water, light, temperature, and nutrient availability are in abundant supply.





What is biodiversity?
•Biodiversity means having as wide a range of different species as possible.
•Maintaining biodiversity is an important part of using the environment in a sustainable way.
•Indiscriminate use of the environment, for example cutting down large areas of the rain forest to grow crops such as soya, results in a large number of species becoming extinct and reduces biodiversity.
•It is only now that we are beginning to realize the potential medicines and crops that we can obtain from a wide range of different organisms.


• Only by maintaining biodiversity can we be sure that these benefits will be available for future generations.




Biodiversity as a genetic resource
•Cultivation began when humans learnt to plant the seeds from wild plants in a field.
•At first crop yield was low.
•Over time, we started using selective breeding-seeds from the larger and more successful crops.
•Later,with improvement in technology-genetic engineering was used –introducing hybrid variety of seeds and crops.

Wild species are getting diminished

Posted in: Biology,EVM