Friday, July 25, 2014

Four basic principles of ecology

The four basic principles of ecology are:
(i) Holism
(ii) Ecosystem
(iii) Succession
(iv) Conversation.
Holism has been considered as the real base of ecology. 

Importance of Environmental Studies

Environment studies enlighten us, about the importance of protection and conservation of our indiscriminate release of pollution into the environment. Environmental issues have grown in size and complexity
day by day, threatening the survival of mankind on earth. We study about these issues besides suggesting effective solutions to these problems.

Environment Issues Being of International Importance
It has been recognized that environment issues like global warming, ozone depletion, acid rain, marine pollution and biodiversity are not merely national issues but are global issues and hence must be tackled with international efforts and cooperation.

Problems Cropped in The Wake of Development
Development, in its wake gave birth to Urbanization, Industrial Growth, Transportation Systems, Agriculture and Housing etc. When the West developed, it ignored of the environmental impact of its activities. Such a path is neither practicable nor desirable.

Increase in Pollution
World census reflects that one in every seven persons in this planet lives in India. With 16 per cent of the world's population and only 2.4 per cent of its land area, there is a heavy pressure on the natural resources including land. Agricultural experts have recognized soils health problems like deficiency of micronutrients and organic matter, soil salinity and damage of soil structure.

 Need for An Alternative Solution
It is essential, for developing countries to find alternative paths. A goal needs to be developed as described below:

  • A goal, which ultimately is the true goal of development an environmentally sound and sustainable development.
  • A goal common to all citizens of our earth.
  • A goal to prevent the developing world from the over-consuming wasteful activities of the “developed” world.

Need To Save Humanity From Extinction
It is necessary for us to save the humanity from extinction. Consequent to our activities constricting the environment and depleting the biosphere, in the name of development.

Need For Wise Planning of Development
Our survival and sustenance depend. Resources withdraw, processing and use of the product have all to by synchronize with the ecological cycles in any plan of development. Our actions should be planned ecologically for the sustenance of the environment and development.

Environmental Studies - Introduction

The word environment is derived from the French word “environner” which means to encircle or surround. Thus our environment can be defined as the physical, chemical and biological world that surround us and the complex social and cultural conditions affecting an individual or community.

This broad definition includes the natural world and the technological environment as well as the cultural and social contexts that shape human lives. It includes all factors living and nonliving that affect an 
individual organism or population at any point in the life cycle.

The three reasons for studying the state of the environment are listed below.
  • There is a need for information that clarifies modern environmental concepts like equitable use of natural resources and a sustainable life style.
  • There is a need to change the way in which we view our environment, using practical approach based on observation and self learning.
  • There is a need to create a concern for our environment that will trigger pro-environmental action including simple activities we can do in our daily life to protect it.
Environmental studies is essentially the application of scientific methods and principles to the study of environmental issues. It is a multidisciplinary subject and its components include Biology, Geology, Chemistry, Physics, Engineering, Sociology, Health Sciences, Anthropology, Economics, Statistics and Philosophy. An Understanding of the working of the environment requires the knowledge from wide ranging fields. Environment is not a single subject, it is an integration of several subjects that include both science and social studies.
Thus, the scope of environmental studies extremely wide and covers some aspects of nearly every major discipline. 

Tuesday, July 1, 2014

ENERGY FLOW IN AN ECOSYSTEM

ENERGY FLOW IN AN ECOSYSTEM

Energy is the capacity to do work. Energy that runs ecosystems ultimately comes from the sun. Green plants trap solar energy through photosynthesis; convert it into chemical energy and store it in the form of chemical energy. The conservation and expenditure of energy is described by the two laws of thermodynamics. The first law states that energy can neither be created nor destroyed but only be converted from one form to another and the other law states that when energy is converted, there is a loss of energy in the form of heat.
In an ecosystem when the energy is transferred from one trophic level to the other, only a part of it is utilized and the rest is wasted or dissipated (in accordance with the second law of thermodynamics).
The energy production in the ecosystem is categorized into primary production and secondary production.

Primary production: Green plants are capable of fixing only 1.5% of the solar energy reaching the earth. This level is called primary trophic level. The plant tissues convert this solar (radiant) energy to chemical energy.

6CO2     +             6H2O                     hυ                           C6H12O6              +             6O2

Only a part of this chemical energy is utilized by plants for their metabolic activities and the rest is taken up by heterotrophs or consumers belonging to the next trophic level. As a result the energy is transferred from one trophic level to the second trophic level.

The glucose produced in the plant cell is either stored in the form of starch or combined with other sugar molecules forming specialized carbohydrates like cellulose. It may also combine with Nitrogen, Phosphorus and Sulfur which help in synthesis of complex molecules like proteins, nucleic acids, pigments and hormones. All these are necessary for the normal growth of the plant, maintenance of body tissues and carrying out various physiological activities. Carbohydrates are oxidized to give Carbondioxide, water and chemical energy.

C6H12O6              +             6O2                                       6CO2     +             6H2O     +             Energy

The total amount of energy converted into sugar by a plant (by photosynthesis) is called ‘Gross primary production’ or ‘Gross productivity’. Some of this energy is lost through respiration and when it is deducted from gross primary production the remaining energy is known as ‘Net primary production

Secondary production: In an ecosystem, the potential energy derived from the primary production meets the energy demands of the other trophic levels. Some of the primary production is consumed by herbivores and omnivores in the form of food. These consumers are in-turn eaten by carnivores of higher trophic levels. No animal can digest or assimilate all the food it has eaten. For example, a herbivore can assimilate only 10% of the food it ingests and in the case of carnivores it may go up to 20%. The energy thus assimilated is retained in the body of consumers in different forms. The food that cannot be digested leaves the animal bodies as feces which is an important source of energy for detritus feeders and saprotrophs.

A part of the energy assimilated by the herbivores is utilized in various metabolic activities like respiration, excretion, secretion, locomotion and reproduction. The remaining is stored in their tissues. This energy is called ‘Net secondary production’. The ‘Gross secondary production’ is equivalent to the total plant material ingested by herbivores minus the matter lost as feces.

The energy flow through different stages of an ecosystem occurs as shown below:

Solar energy                       Producers                           Primary consumers                         Secondary consumers  
                                                (Green Plants)                  (Herbivores)                                      (Primary carnivores)
 


Tertiary consumers

(Secondary carnivores)