Environmental Factors

ENVIRONMENTAL FACTORS

1.      Climatic Factors

A.    Light

a.       Effect of Light on Plants

Light plays a vital role directly or indirectly in regulating the growth, metabolism, development and distribution of plants.

·         Effect on chlorophyll synthesis

·         Effect on number and position of chloroplasts

·         Effect on photosynthesis

·         Effect on respiration

·         Effect on transpiration

·         Effect on production of hormone

·         Effect on development of flowers, fruits and vegetative parts

·         Effect on formation of Anthocyanin pigments

·         Effect on movement

·         Effect on photoperiodism

·         Effect on seed germination

·         Effect on distribution of plants

·         Effect on photo-morphogenesis

b.      Effect of Light on Animals

·         Effect on reproduction

·         Effect on metabolism

·         Effect on development

·         Effect on pigmentation

·         Effect on locomotion

·         Photoperiodism

·         Effect on eyes

B.     Temperature (measurement of the degree of heat)

Heat is a form of energy.

a.       Effect of Temperature on Plants and Animals

In affecting the structure physiology, growth and distribution of plants and animals, temperature plays am important role.

·         Effect on cell and protoplasm

·         Effect on metabolism

·         Effect on respiration

·         Effect on development

·         Effect on growth

·         Effect on transpiration in plants

·         Effect on  Reproduction

·         Effect on sex-ratio

·         Effect on morphology

·         Effect on colouration

C.     Water

Water is an indispensable parts of land and soil productivity. The misuse of water leads to soil degradation and erosion. All the physiological processes take place in the medium of water. Protoplasm,  the very basis of life, is madeup mostly of water.

D.    Rainfall

The rainfall occurs due to interchange of water between earth’s surface and the atmosphere. This is known as the hydrologic cycle. In this cycle two important things are precipitation and evapo-transpiration. Annual rainfall determines the types of vegetation in any region. Vegetation causes changes in the types of forest, animal and birds.

E.     Wind

It affects plants, and other organisms. It modifies the water relation and light conditions of a particular region. The wind accelerates transpiration, removes solid moisture and at high velocities causes soil erosion.

F.      Humidity

Humidity is greathly influenced by intensity of solar radiation, temperature, altitude, water status of soil, etc. Low temperature causes higher relative humidity by decreasing the capacity of air for moisture. Processes as transpiration, absorption of water, etc. are influenced by atmospheric humidity. Humidity, thus plays an important part in the life of plants and animals.

G.    Atmospheric Gases

Some principal gases like nitrogen, oxygen, methane, etc. are found in atmosphere. In addition to these gases, there are water vapours. Industrial gases, dust, smoke particles, micro-organism, etc. are present in the atmosphere.

2.      Edaphic Factors

Edaphic factors deals with different aspects of soil, such as the structure and composition of soil, its physical and chemical fetaures.

A.    Definition

The soil is a result of the actions and reciprocal influences of parent rocks, climate, topography, plants, animals and age of the land. The interactions among climatic, topography and biological factors save the process of transformation and modification of mineral matter into soil. Mainly components of soil are mineral matter, humus, soil water, soil atmosphere and biological system.

B.     Formation of Soil

The soil development may be classified into two major phases :

1.      Weathering of parents rock

2.      Maturation and profile development

C.     Soil Erosion

The nutrients required by plants are present in the top layer of the soil. It is very fertile and usually lies at a depth of 15-20 cm over the face of land. Soil erosion is the results of deforestation, flood, over grazing, etc.

D.    Soil Consevation

·         Protection of soil from the severity of rain drops.

·         To prevent water from concentrating and passing through the slopes

·         To slow down the momentum of water flow through various scientific techniques

·         To plan out methods by which water can adequately enter into soil

·         Growing vegetation cover and thereby to minimize the wind velocity

·         Soil binders like growth of grasses can prevent soil erosion etc.

3.      Topographic Factors

These factors influence vegetation which causes variation in climate of a geographic region, ultimately give rise to a characteristic microclimate. The different topographic factors are :

1.      Altitude of the place

2.      Steepness and exposure of the slope

3.      Direction of the mountain chains

4.      Biotic Factors

The biotic factors constitude the living organisms of the environment and definitely they have their interactions. Symbiosis means interaction of living organisms which are naturally beneficial. There are many kind of symbiosis.

5.      Limiting Factors

A limiting factor is that substance of quality in the environment, j the supply of which is least abundant or over abundant in relation to the need of the living organism concerned. Limiting factors are of two types on the basis of their correlation with population density :

A.    The Density Dependent Limiting Factor

The effect of such type of limiting factor has direct correlation with population density.

B.     The Density Independent Limiting Factors

The effect of such type of limiting factor is limited to many or few individuals without reference to the population level.

           The effect of some important limiting factors on living organisms are discussed below :

1.      Climatic and atmospheric factors

2.      Soils

3.      Water

4.      Biotic factors

Every environmental factors has to zone :

a.       Zone of tolerance

This zone is favourable for the growth and development of the organisms which may be further subdivided into three sub-zones :

1.      Optimum zone

2.      Critical minimum zone

3.      Critical maximum zone

b.      Zone of intolerance

It is the zone below the critical minimum and above critical maximum. This zone is unfavourable for the survival of the organism for a longer period of time.

Thus, in the environment, the organisms are controlled by :

1.      The quantity variability of materials for which there is a minimum requirement

2.      The physical factors which are critical

3.      The limits of tolerance of the organisms themselves to these and other components of environment.

Secara garis besar, faktor-faktor lingkungan dapat dibagi menjadi dua jenis, yaitu :

1.      Abiotik

2.      Biotik

References

Campbell, Neil A., dkk. 2012. Biologi Edisi Kedelapan Jilid 3.Jakarta : Penerbit Erlangga.

Pollution, environmental. Environmental Factors. http://www.environmentalpollution.in/environment/5-ecological-factors-that-constitute-the-environmental-of-an-organism/178. Online (diakses tanggal 25 Januari 2017).