Abiotic factors that affect communities
The abundance of organisms in an ecosystemThe living organisms in a particular area, together with the non-living components of the environment. and their distribution is affected by abioticNon-living elements of an ecosystem, such as climate, temperature, water, and soil type. factors. These are factors that are non-living.
They include:
- light intensity:
- light is required for photosynthesisA chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic., and plant speciesA type of organism that is the basic unit of classification. Individuals of different species are not able to interbreed successfully. have evolved for optimumThe best or most appropriate - for instance, the conditions under which an enzyme works best (eg temperature and pH). growth in the light available in their climate or habitatA place where plants, animals and microorganisms live.
- temperature:
- animals and plants have evolved to grow healthily at their optimum temperatures
- moisture levels:
- animals and plants are adapted to growing at the moisture levels available
- most plants are killed by waterlogging, as they are unable to respirationThe chemical change that takes place inside living cells, which uses glucose and oxygen to release the energy that organisms need to live. Carbon dioxide is a by-product of respiration.
- bog plants will be adapted to growing in these wet conditions
- soil pH and mineral content:
- many plants are sensitive to pH
- plants such as heathers, grow best in acidicHaving a pH lower than 7. soils
- plants such as lavender, prefer alkalineHaving a pH greater than 7. soils
- wind intensity and direction:
- wind can increase the supply of carbon dioxide to plants
- but wind increases the rate of transpirationThe loss of water from leaves by evaporation through the stomata. and therefore water loss
- wind can cause mechanical damage to plants
- carbon dioxide levels for plants:
- carbon dioxide is required for photosynthesis, so increased concentrations will increase growth and crop yieldThe amount of a crop harvested, usually represented as the mass from a certain area.
- some plant growers therefore raise the concentration of carbon dioxide in greenhouses for increased growth
- carbon dioxide is an acidic gas, and because some plants are sensitive to pH, this is not suitable for raising yields of all plants
- oxygen levels for aquatic animals:
- oxygen dissolves in water and is required for the animals' respiration
- moving lakes and rivers have high levels of oxygen
- stagnant and polluted waters often have low levels of oxygen
- animals such as sludgeworms can survive low oxygen levels
- some animals are indicator speciesThe presence, abundance or absence of these organisms provides information such as the level of pollution in the environment. species because their presence or absence informs us about the condition of the habitat
