BCA Study Material Notes Of Environment Studies Unit 3

BCA Study Material Notes Of Environment Studies Unit 3

BCA Study Material Notes Of Environment Studies Unit 3

BCA Study Material Notes Of Environment Studies Unit 3

In a deciduous forest, biome spring brings release form dormancy & a resurgence of vegetative activity culmination in leafing out in deciduous trees. Leaf fall brings the onset of dormancy & curtailment of activity manifested in leaf colour  change & fall. The natural geophysical phenomenon reach at different interval & as different species respond deferentially to such stimuli, different rhythms would be expected, a prior, among different communities. Photoperiods have major effect on plant behavior. ccsusmaplepapers is that site students will easy to learn our syllabus and get great marks in examination we will provide for you like Sample papers, Modal paper, also have Examination paper, Mock papers, students there is confuse how exam paper is come in examination we also provide Important question, Previous papers, Bca study Material, Study guide ect here is all solution of your problem you have if you like my site them you also share this to your friends classmate.  

BCA Study Material Notes Unit 3 Ecosystem
BCA Study Material Notes Unit 3 Ecosystem


The term ecosystem was coined by Tinsley (1935). Ecosystme is the structural & functional unit of biosphere, comparing living beings & their non-living environments. The ecosystem may be temporary (rainfed pond) or ocean (macro-ecosystem).

Function of Ecosystem

  1. Production of food by autographs, chemo autographs.
  2. Use of solar energy by green plants.
  3. Recycling of minerals.
  4. Helps in maintaining CO2/O2 ratio in atmosphere.
  5. To maintain flow of energy.
  6. Ecosystem is a discrete structural, functional & life sustaining environmental system.

Photoperiodism & Ecotypes

The species has a specific physiological, response to photoperiodism as it has a specific morphological adaptation to another environmental parameter. Charis Olmsted demonstrated that different population of a common prairie grass known as side-oats grama (Bouteloua curtipendula did not have identical response to give photoperiods. Long day plants demonstrate normal vegetative & flowering behavior only with photoperiods of 14 hours or longer. Short day plants, functions normally under 13 hours of light but failing to bear flower on photoperiods longer than 14 hours. Alpine sorrel (Oxyria digyna) requires 15 light for flowering. There is physiological difference in population at different latitudes. Northern populations have more chlorophyll, higher respiratory rates at the same temperature & an attainment of peak photosynthesis at lower temperatures.

Flow of energy in the Living World

The radiant energy that originates in thermonuclear reactions in the sum reaches to earth in the form of light ( & other forms of radiation ) & sustains all living organism. Over the entire globe about 25% of the incoming solar radiation is scattered or reflected by the atmosphere back into the space. This fraction of arriving solar energy is lost to thee earth. Another 25% is absorbed by the atmosphere. The remaining 50% that manages to reach the earth. Surface. Some 45% of he total is absorbed as heat by lands or oceans; 5% (of the total) is reflected back into space; 24% is consumed in promoting water evaporation & related meteorological (weather) phenomena. A very small fraction drivers the winds & waves. An even smaller fraction is captured by the leaves of green plants. Indeed, the total solar energy reaching on earth per year is said to equal 1,73,000*1012  watts. Of this, only 40*1012  Watts is used in photosynthesis.

Distribution of the radiation reaching on earth
Distribution of the radiation reaching on earth

Flow of Energy though Different Trophic Levels

  1. Sunlight is trapped by autotrophs which prepares food through photosynthesis.
  2. This energy is taken by herbivores, then carnivores & top carnivores.
  3. Large amount of energy is lost at each trophic level. Only 10% of energy is passed form one trophic level to other, i.e. (Lindmann)

Autotrophs               Herbivores                   Carnivores                Top Carnivores

   100%                                10%                                1%                             0.1%

  1. Energy lost due to heat or respiration cannot be transferred to any organism.
  2. Decomposition due to heat or respiration cannot be transferred to any organism.
  3. In shorter food chain, more energy is available in comparison to longer food chain.
  4. The energy always flows unidirectional i.e from autotrophs to herbivores & then to carnivores.
Flow of energy
Flow of energy

Marine Ecosystem

Seas & oceans have high concentration of salt (3.5%) & minerals. The main minerals are sodium, chloride, sulphur, calcium & magnesium.

Features Of Ocean

  1. Continental Shelf : It is a zone with a depth of 8-200 mts.
  2. Continental Slope : The shelf drops off abruptly. It usually has ridges, basin, trenches, formed of mud & sand. It may extend from 200-300 mts.
  3. Ocean Floor : The slops levels off into a more or less horizontal area forming the ocean floor. The depth may be 7000 mts or more.
  4. Trench : It is a narrow deep region. It can be as deep as 10,000 mts.

Vertical Zones

  1. Euphotic Zone (Photic zone) : It extends to 200 mts. From the surface. It is a thin zone through which light can pass.
  2. Aphotic Zone : It ranges form 200-2000 mts. Gets less light comparatively but photosynthesis is possible.
  3. Abyssal Zone : It is a dark region lying below 2000 mts.


  1. The Littoral Zone : It represents an area form shore to edge of continental shelf. It is euphotic zone.
  2. Benthic Zone : It is formed by continental slope extending into the ocean floor. It includes aphotic & abyssal zone.
  3. The Pelagic Zone : It constitutes the open sea & has variety of flora & fauna. It has euphotic, aphotic & abyssal zone.
Different Zones in ocean
Different Zones in ocean

Sulphur cycle

Sulphur is an important part of some amino acids. It is aborted by plants as sulfates.Its main sources is earth’s crust.

The sulphur is released back to soil by decomposition. Microbes convert sulphur to sulphates. In marshes un

der anaerobic conditions. Sulphur may be converted to sulphides by bacteria. Sulphides may be oxidized to sulphates. Sulphur may be added to atmosphere as oxides (SO2) due to the burning of fossil flues or by volcanic activities or smelting of Sulphur ores & factories.  

Sulphur cycle
Sulphur cycle

Oxygen Cycle

Oxygen is an essential elements. It is found as O2 in atmosphere & as compound like H2O & CO2

Oxgen cycle
Oxgen cycle

Water cycle

Water is important constituent of living cells. Water may exist in gaseous, liquid or solid state.

In global water cycle, water evaporates form water bodies (oceans, rivers, lakes) & forms clouds. The water vapor in clouds cools condenses to form rain snow.

The water may fall directly into oceans or may flow to ocean through rivers or underground water. Some water of landmass may seep in as ground water. Some water may remain as perennial snow on mountain peaks or in polar regions.

In smaller cycle, the environmental water moves in living organism & back to environment. Aquatic animals take water directly & give it back through excretion etc. Land animals take water directly or as food form plants or other animals. In case of plants, water is absorbed by roots and returned to atmosphere through transpiration.

Water cycle
Water cycle

Forest & Grassland Ecosystem 

Forest & Grassland Ecosystem
Forest & Grassland Ecosystem

Short note on “Efforts of eco-development is Indian”

In Indian context, the exclusivity of Protected Areas (PA). as envisaged in the developed countries is not possible, due to human dominated landscape in & around them. The population is largely rural that draws on the resources of the PA for subsistence. A participatory management strategy of protected areas, eco-development aims at conserving the bio-diversity by addressing both the impact of local people on the protected areas & the impact of the protected areas on local people, In response to the changed paradigm of partnership, Eco-development Committees (EDCs) emerged around many. Pas. Te National Afforestation & Eco-development Board (NAEB), set up in August 1992, is responsible for promoting afforestation, tree planting, ecological restoration & eco-development activates in the country, with special attention to degraded  forest areas & lands adjoining the forest areas, national parks, sanctuaries & other protected protected areas & as well  as the ecological fragile areas like the Western Himalayas; Aravallis, Western Hgats etc. The detailed role & function of the NEAB are given below.

Periyar Tiger Reserve (PTR) in Kerala is one among the seven Pas in Indian selected for the implementation of IEP. In accordance with the tripartite agreement signed between the external donor agencies (World Bank & IDA). Government of India (GOI) & Government of Kerala (GOK). Eco-development Committees were constituted.

Goal : The goal of the project is conservation of bio-deversity through people’s participation.

Objective :

  1. To improve capacity of PA management in conserve bio-diversity & increase opportunities for local participation in PA management.
  2. To reduce negative impact of local local people on biodiversity, reduce negative impact of PA on local people, & increase collaboration of local people in conservation efforts.
  3. To develop more effective & extensive support for community development activities.
  4. Evolve mechanisms for ecological restoration of degraded forest areas & adjoining lands through systematic planning & implementation, in a cost effective manner.
  5. Restore through natural regeneration or appropriate intervention the forest cover in the country for ecological security & to meet the fuel wood, fodder & other needs of the rural communities.
  6. Restore fuel wood, fodder, timber & other forest produce on the degraded forest & adjoining lands in order to meet the demands for these items.

Previous Post-

BCA Natural Resources Study Material Notes Unit 2

Also Follow me :-




Leave a Reply

Your email address will not be published. Required fields are marked *