The environment is the natural component in which biotic (living) and abiotic (nonliving) factors interact with each other. This interaction between biotic and abiotic components of the environment shapes the habitat and ecosystem of an organism.
Components of an Ecosystem
There are two main components of an ecosystem which are in constant communication with each other. They are the biotic and abiotic components.
The components of the ecosystem are categorized into abiotic or non-living and biotic or living components. Both the biotic and abiotic components of the ecosystem and environment are the same.
Biotic and abiotic components of the ecosystem
Abiotic components are the inorganic and non-living parts which act as major limiting factors.
- a lot of factors determine the survival of an organism. One single factor can limit the range of an organism. This single factor is called as a limiting factor.
- For example, seeds don’t germinate quickly in evergreen rainforests in spite of good rains and vegetation as the surface soil is heavily leached (nutrients washed away by running water). Here, poor soil is the limiting factor.
- Likewise, germinated saplings may not survive due to lack of light because of the dense canopy. Here, light [shade of the forest] is the limiting factor.
- Light: The spectral quality of solar radiation is important for life. The UV component of the spectrum is harmful to many organisms.
- Rainfall: Majority of biochemical reactions take place in an aqueous medium. These biochemical reactions are important for the survival of an organism. So rainfall is an important limiting factor.
- Temperature: Latitudinal insolation decides the temperature range of a region. A few organisms can tolerate and thrive in a wide range of temperatures (they are called eurythermal), but, a vast majority of them are restricted to a narrow range of temperatures (such organisms are called stenothermal).
- Atmosphere: 21% oxygen helps in the survival of many organisms, 78% nitrogen prevents spontaneous combustion and 0.038% carbon dioxide helps primary producers in the synthesis of carbohydrates.
- Organic compounds: Proteins, carbohydrates, lipids etc. are essential for energy transfer in the living world.
- Inorganic compound: Carbon, carbon dioxide, water, sulfur, nitrates, phosphates, and ions of various metals are essential for organisms to survive.
- Altitude: Vertical zonation of vegetation is caused due to altitude. Change in temperature with altitude is the limiting factor.
- Buffering capacity of the earth: The most unique feature of the earth is its buffering action due to which a neutral pH (pH- 7) is maintained in the soil and water bodies.
- The neutral pH is conducive for the survival and sustenance of living organisms.
- Salinity: Some organisms are tolerant of a wide range of salinities (euryhaline) but others are restricted to a narrow range (stenohaline). So salinity is a limiting factor.
Effect Of Abiotic Components On Terrestrial Primary Producers – Plants
Plants are the reason that the other animals are able to survive on land. So the effect of abiotic factors on plants is crucial.
- Extremely high intensity favors root growth than shoot growth which results in increased transpiration, short stem, smaller thicker leaves.
- On the other hand low intensity of light retards growth, flowering and fruiting.
- When the Intensity of light is less than the minimum, the plants cease to grow due to the accumulation of CO2 and finally dies. Out of 7 colours in the visible part of the spectrum, only red and blue are effective in photosynthesis.
- Plant grown in blue light are small, red light results in elongation of cells result in etiolated plants. Plants grown in ultraviolet and violet light are dwarf.
- Frost results in freezing the soil moisture. The plants growing in such soil, get exposed to direct sunlight in the morning, they are killed due to increased transpiration when their roots are unable to supply moisture. This is the main reason for innumerable death of sal seedlings.
- As a result of frost, water in the intercellular spaces of the plant gets frozen into ice which withdraws water from the interior of the cells. This results in increasing concentration of salts and dehydration of cells.
- Thus coagulation and precipitation of the cell colloid result in the death of a plant. Also, frost leads to the formation of canker.
- Snow acts as a blanket, prevents a further drop in temperature and protects seedlings from excessive cold and frost.
- Accumulation of snow on tree parts can break the branches or even uproot the tree. Snow shortens the period of vegetative growth.
- High-temperature results in the death of plant due to coagulation of protoplasmic proteins [Some bacteria can survive high temperatures because of their protoplasmic proteins that don’t coagulate at normally high temperatures].
- High temperature disturbs the balance between respiration and photo synthesis thereby causes depletion of food resulting in greater susceptibility to fungal and bacterial attack.
- It also results in desiccation of plant tissues and depletion of moisture.
components which are the living things that shape an ecosystem called biotic component. Examples of biotic components include animals, plants, fungi and bacteria.
Primary producers – Autotrophs (self-nourishing)
Primary producers are basically green plants, certain bacteria and algae that carry out photosynthesis.
In the terrestrial ecosystem, grasses, plants and trees are the primary producers while in the aquatic ecosystem, microscopic algae [plankton] are the primary producers.
Consumers — Heterotrophs or Phagotrophs (other nourishing)
Consumers are incapable of producing their own food. They depend on organic food derived from plants, animals or both.
Heterotrophs or Phagotrophs can be divided into two broad groups namely micro and macro consumers.
Herbivores are primary consumers which feed mainly on plants e.g. cow.
Secondary consumers feed on primary consumers e.g. wolves, dogs, etc.
Carnivores which feed on both primary and secondary consumers are called tertiary consumers e.g. lion which can eat wolves, snakes etc.
Omnivores are organisms which consume both plants and animals e.g. man, bear, etc.
Micro consumers – Saprotrophs (decomposers or osmotrophs)
They are bacteria and fungi which obtain energy and nutrients from dead organic substances (detritus) of plant and animals.
The products of decomposition such as inorganic nutrients which are released in the ecosystem are reused by producers and thus recycled.
Earthworm and certain soil organisms (such as nematodes, and arthropods) are detritus feeders and help in the decomposition of organic matter and are called detrivores.