Top 5 Factors of Biosphere | Environment | Environmental Engineering

Following factors of the biosphere are included in the non-living environment: 1. Soil 2. Water 3. Air 4. Temperature 5. Light.

Factor # 1. Soil:

(A) Soil Formation and Composition:

Soil is formed by gradual weathering of various types of rocks. Under the soil lies the hard rocky crust, which is the parent material from which it is formed. The thickness of the soil varies from few centimetres to several meters.

The soil is made up of the:

(i) Mineral matter,

(ii) Organic matters and soil organisms,

(iii) Soil water, and

(iv) Soil-air.

Some part of the mineral matters derived from the parent rocks is soluble in water and the remaining is insoluble in water.

The soil may be classified as:

(i) Sandy soil,

(ii) Clayey soil,

(iii) Loamy soil.

Organic matters formed by the decomposition of plant and animal remains are also found in the soil. Various types of living organisms known as soil-organisms are also found in the soil. These are known as micro-organism, microflora and microfauna.

(B) Organic Matters in Soil:

The soil fungi are mostly found in acidic soils. It may be parasitic, saprophytic or symbiotic type. The parasitic type fungi produce toxins, which cause various types of plant diseases. The saprophytic type fungi derive nourishment from the dead and decaying organisms by decomposing them. The symbiotic type fungi live on the roots of certain plants and benefit them.

The actionomycetes fungi are mostly found in saline soils. These feed on the dead and decaying organisms by decomposing them and produce various types of antibiotics during the process.

The algae add up to the organic matter of soil. The macro-organism eat the micro­organisms and maintain their balance. The earth worms make the soil porous by boring through it, consuming organic matters and large quantity of soil.

(C) Soil Water:

The quantity of water retained in the soil depends upon countless interspaces of varying shapes and sizes of the soil particles. The narrow spaces are known as capillary interspaces, whereas the large ones are known as non-capillary interspaces.

The water retained in the soil, can be classified as follows:

(i) Gravitational Water, which moves down in the soil, due to gravitational force.

(ii) Capillary Water, which remains in the capillary interspaces of the soil particles. This water is always available to the plant life.

(iii) Water Vapour, are available in the shape of moisture in the soil atmosphere.

(iv) Hygroscopic Water is thin film on the soil particles, which is not available to the plants.

(v) Combined Water, is the quantity of water chemically bound with the soil minerals.

(D) Soil Air:

Gases remain in the soil particles. Air spaces found in between the soil particles, hold the gaseous system of the soil, which is continuous with the outer atmosphere. For the plant growth, soil air is necessary because oxygen contained in the air breaks down insoluble soil minerals into soluble salts, which are used by the plants. Presence of soil-air is necessary for the respiration of soil micro-organisms.

When the soil air quantity is less, it results in accumulation of carbon-dioxide causing formation of hydrogen sulphide, formic acetic, oxalic and some toxic acids. These toxic substances kill the soil organisms. Excessive carbon- dioxide is also responsible for the development of low pH-value, which prevents nutrients from reaching the plants.

Factor # 2. Water:

(A) Water Importance to Organism:

Water plays very important role in the life process such as:

(i) Transportation of materials in the body tissues,

(ii) Removal of excretory wastes from the body,

(iii) Exchanges of gases etc.

As the specific heat of the water is high, it gets heated and cooled slowly. It can easily receive or give off a large amount of heat without considerable change in its temperature. This quality of water regulates the temperature of plants, animals and human beings.

Water has good solvent power, which plays very important role. Most of the nourishment reaches in solution form with the water in animals, plants and human beings. The digested food is absorbed by blood and tissues in the dissolved state.

Water also has highest heat conductivity. It uniformly distributes the heat over the entire body, thus keeping constant temperature of the body. The heat produced by the cell is conducted immediately by the water and evenly distributed to the entire body.

As the viscosity of water is higher than other solvents, therefore it protects aquatic animals against mechanical disturbances. At 4°C, density of water is highest. Below 0°C, water becomes ice (in solid form). Between 0°C and 100°C it remains in liquid form and above 100°C, it becomes vapour/steam.

The freezing point of fresh water is 0°C and that of sea water is -2.5°C. The density of ice being lower, it float on the surface of water, thereby the aquatic life at deeper depths of the water remains undisturbed.

The water has good transparency, which facilitates the passage of light to greater depths. It increases visibility for aquatic animals.

(B) Water Influence on Organism:

Rain water is the main source of water. The nature of vegetation mainly depends on the amount of rain fall in a particular area. In dry countries like Africa with the advance of summer the water dries up leaving small number of ponds and lakes. The wild life migrates around these water sources.

With the rains the grass appears at the surface of the soil. All ponds are filled up with water, so the wild life, birds, animals etc. start spreading around them. Without water no one can survive.

(C) Water Adaptations by Organisms:

Water available in the nature may be fresh water, esturine and marine or sea water. Contents of the dissolved materials vary in the water from place to place and make water isotonic, hypertonic or hypotonic to the body fluids of the animals.

The animals have to maintain water balance in various ways. When the osmotic pressure of the body fluid is equal to that of water in which it lives (isotonic medium), there is no difficulty in maintaining the water balance.

The salinity of sea water is about 3.5%, therefore the osmotic pressure of water is more than that of the body fluids of the animals (hypertonic medium). Animals living in such water have loose water from their body for maintaining water balance. Therefore, such animals have to drink water in order to make up the loss of water.

In the case of fresh water the salinity varies from place to place, but the osmotic pressure remains always less than that of the body fluids of the organisms. Such animals also take water. In salt lakes, where salinity reaches 25% to 30%, all lives are killed. Due to the above reasons there are great variations in the marine and fresh water organisms.

(D) Water Adaptations of Terrestrial by Animals:

All the organisms living on land maintain a proper water balance between themselves and the environment. As the quantity of the water available on the land is not plenty, the animals are in constant danger of dessication. For this reason water is conserved by them. Certain desert animals develop a thick horny skin, which is impermeable to water and prevent water loss by evaporation.

Some animals like rodents and antelopes nearly or completely lack sweat glands. Some animals burrow deep into the moist soil to avoid water loss.

There is no loss of water by evaporation through the body surfaces of exoskeleton of insects, spiders and the shells of molluscs, because it is impermeable to water. The carnivora of desert get their requirement of water from the blood of their prey. Some insects get water from the plant food only.

Rats of the desert depend upon metabolic water. The camel gets metabolic water by oxidation of fat of its hump and it stores water in special compartments in its stomach. Some desert animals conserve body water by excreting their nitrogenous waste as solid uric acid; their faecal waste is also dry. It has been seen that some animals produce resistant eggs, which have egg cases impervious to water.

(E) Destructive Effects of Water:

Floods, erosion of soils and submergence of lands are some of the destructive effects of water. When large quantity of soil is removed during construction of tube-wells and tunnels without proper protections, it makes the surface soil unstable.

Similarly too much removal of water by tube-well or during dewatering for making of dam foundation or other irrigation structures, make the area unstable, thereby endangering life and property. Floods cause loss of life and properly every year in India.

Stagnant water around localities breed mosquitoes, which endanger the health of peoples living in the area. During rains, snow, hail and sleet may cause damage to the crops and vegetation and may hurt the peoples and animals. Heavy sleet and snow may cause heavy damage to buildings, trees, shrubs and grass. In this way, it will be important to note that water has also vast destructive effects.

Factor # 3. Air:

Air around the earth mainly consists of oxygen, nitrogen and carbon dioxide. In addition to these gases some amount of water vapour, inert gases and small percentage of hydrogen, helium, hydrogen sulphide, sulphur-dioxide etc. are also present in the atmosphere. All these gases are present in the atmosphere simply as mixture of gases. These are not chemically combined.

Weight of earth’s atmosphere is about 60,000 billion tons. It constantly exerts pressure on each and every organism, animals, human, creatures etc. At mean sea-level its pressure is about 1.0 kg/sq.cm. As the air molecules are under gravitational force, therefore more molecules are held near the earth than at higher altitude. Practically, 90% of the weight of the atmosphere is contained in first few kilometres and remaining 10% in the balance atmosphere.

As we move higher up from the earth’s surface, density of the atmosphere decreases. At 5500 meters above the mean sea level the atmospheric pressure become half which is at sea-level i.e., 0.5 kg/sq.cm. If a man reaches to a much higher altitude, say 20,000 metres, without any protection, his blood will start boiling (because at lower pressure, the boiling point is also low).

At higher altitudes the amount of oxygen is also low, which is not sufficient to satisfy the man’s requirement. Therefore, at higher altitudes, oxygen gas cylinders are necessary. Keeping in view, this problem, the jet planes and space suits are made air-tight and the air pressure inside is always kept constant so that passengers remain under natural conditions. The above problem at higher altitudes make animals and people sparser and sparser as they go higher and higher.

At higher altitudes the height of the plants and trees become low, because at higher altitude concentration of oxygen and carbon-dioxide become low. This reduces the photo­synthesis and metabolic activity. At higher altitudes the intensity of ultra-violet rays also increases, which makes unfavourable environment for living purposes. At Mount Everest, there is only snow because at such heights nothing grows.

For the variety of vegetation’s and trees, wind and air currents are also responsible. In the areas where wind velocity is high, strong rooted trees and vegetation grows. In the areas with low velocity winds, vegetation with moderate roots grows. The distribution of seeds and spores also depends upon the velocity of the wind.

The water vapour contents in the air are known as humidity. At a particular temperature the total amount of invisible water vapour present in the air is known as absolute humidity. Relative humidity is the ratio between absolute humidity to the amount of invisible water vapour required to saturate it at the same temperature.

Humidity plays very important role in the atmosphere. Clouds are formed when the water around the dust particles condense, releasing, the heat energy. When further heat is released, the condensed water is converted into droplets and form dew causing rain falls.

Humidity also influence the rate at which evaporate from the bodies of the organisms. Thus, the efficiency of the organisms greatly depends on the humidity of the atmosphere.

Factor # 4. Temperature:

The biochemical processes of the organisms can occur efficiently only under small variation of temperature suiting the organisms. Temperature is very important factor of environment. Under different climatic conditions, temperature has wide fluctuations.

The fluctuation of temperature is comparatively less in water than on the land. The temperature variation on land may vary up to 45°C. The temperature of the water bodies vary up to 22°C in surface and only up to 5°C in the bottom layers.

The optimum range of temperature, which is comfortable to man is around 15°C to 25°C, when there is no moderate humidity.

The tolerance limit of most of the organisms is between 0°C to 50°C. Most organisms cannot survive below and above these temperature limits.

The man has natural physiological devices to maintain a constant body temperature. In winter when the atmospheric temperature falls below the body temperature, man loose heat to the atmosphere by radiation.

This loss of heat is gained by metabolic activities, which go high to produce more heat. In summer, when the temperature of the environment is high, the heat enters in the body. To get rid of this excessive heat, man starts sweating and its subsequent evaporation.

Following are the various climatic zones on the earth depending on the temperature:

(i) Tropical areas, which do not have winter in any part of the year.

(ii) Sub-tropical area, have hot zones as well as cool winter in the year.

(iii) Temperature areas, have warm summer and good winter.

(iv) Alpine zone areas have smaller summer but long severe winter.

In India all the above four climate zones are available. The western Ghats and Assam has Sub-tropical climate. In Himalayas climate is between temperature to sub-temperate. Upper portions of Himalayas have alpine climate.

Influence of Temperature:

Temperature influences the organisms in the following ways:

(i) Influence on Biochemical Process:

It has been noted that, when temperature exceeds within certain limits, bio-chemical process of the body also exceeds. In some cases the biochemical process doubles, when the temperature exceeds 10°C within limits.

(ii) Influence on Humidity:

In moderate humidity and cool temperature the efficiency of the man increases. The vegetation in particular region is controlled by the combined effect of temperature and humidity.

(iii) Influence on Distribution of Plants and Animals:

Nature and type of vegetation changes from place to place, under different conditions of temperature. Sal wood is mostly found in tropical and subtropical zones at about 1525 meters. Above this altitudes from 1525 to 3660 metres. Sal wood trees become scarce and conifer trees like Chir, Pinus, Deodar, Silver fir.

Spruce and broad leave trees like Oak, Cornus, Chest-nut, elm, poplar etc. are found. The type of vegetation’s between 3660 m to 4750 m, are different. Between 4750 to 8000 m small number of vegetation’s is found. Above 8000 m altitude.

Banana tree is tropical tree and it gives fruit in warm climate only. If it is grown in cold climate, it will produce very small fruits or may not produce fruits. Guava trees cannot live at freezing point temperature.

Below 25°C, the material parasite bacteria do not live on the body mosquitoes. Thus it will be seen that malaria disease is common in tropical marshy regions where the temperature is above 25°C.

(iv) Influence in Reproductions and Growth:

At optimum temperature range, there is maximum reproduction and growth. In temperature regions, growth of terrestrial animals starts during the spring and reaches climax in summer. In case of tropical regions, the growth is maximum in spring and reduces in summer.

Some cold blooded animals like insects, spiders, molluscs including some plants undergo a dorment stage, known as aestivation or summer sleep. Some animals migrate to other places in order to have the optimum range of temperature. Some fishes migrates to the cooler deep waters during summer. Some desert animals live in burrows during day to avoid the hot sun and come out in the night for feed.

Factor # 5. Light:

Light is luminous energy which is visible part of the spectrum of electro-magnetic radiation. It varies from 400 m to 760 m. Sun’s light or solar energy is trapped by the plants during photosynthesis and is converted into chemical energy. When these plants are eaten by the animals, insects and men, this energy goes in them. Thus without light there is no plant, animal or man.

Light influence the organisms in various ways, which are as follow:

(i) Daily cycle of light and darkness exerts a profound influence on the animals. The response of organ isms to environmental rhythms of light and darkness is known as photoperiodism. The time between the sunrise and sunset is known as photoperiod. The photoperiods vary in different regions. It provides the information’s to animals, birds and man regarding the duration and intensities of natural light.

(ii) Light greatly influences the development of animals and man. The natural development of the animal and man take place in better way in light. Body structure also becomes good in the presence of sun’s light. Sun light also greatly influences the pigmentation. The animals living in caves lack pigmentation.

When aquatic animals are removed from light, they loose their colouration. The colourless animals develop pigmentations when exposed to light. Many insects and small aquatic life more fast in high intensity of light and move slow in low intensity light. Locusts stop their flight, even when sun gets hidden by the clouds.