Discuss the role of healthy ecosystem services as a prerequisite for a wide range of economic, environmental and aesthetic goods and services.
Ecosystem services are the products of ecosystem processes. Forests are the major source of ecosystem services and are
prerequisite for environmental, aesthetic goods and indirect economic values in the following ways:
1. Environmental Values
(i) Carbon-fixation Huge amount of CO2 in the atmosphere is removed naturally and fixed by plants into organic
molecules and energy through photosynthesis. All the other trophic levels, i.e. consumers depend upon this
energy produced by them.
(ii) Release of oxygen by the producers as a byproduct in the process of photosynthesis, improves the air quality
and supports life on earth.
(iii) Soil Soil formation and soil protection are the major ecosystem services accounting for nearly 50% of their total
worth. Plant cover protects the soil from drastic changes in temperature. There is little wind or water erosion as
soil particles are not exposed to them. The soil remains spongy and fertile. There are not landslides and no floods.
(iv) Nutrient cycling There is no depletion of nutrients, but the same are repeatedly circulated.
2. Economic Value
(i) Ecosystem services provide certain economical important products also. These include timber, paper, rubber,
wax, medicines, cosmetics, resins, etc.
(ii) Ecosystem also provides other benefits such as aid in pollination. Bees and other insects of natural ecosystem visit
nearby farmlands to pollinate crops.
3. Other aesthetic values Natural ecosystems are a source of spiritual, cultural and aesthetic values.
1. Plants are called as .......................because it fixes carbon dioxide.
2. In ecosystem, dominated by trees, the pyramid is.......................type.
3. In aquatic ecosystems, the limiting factor for the productivity is.......................
4. Common detritivores in our ecosystem are.......................
5. The major reservoir of carbon is.......................
Define ecological pyramids and describe with examples, pyramids of number and biomass.
Give an account of energy flow in an ecosystem.
(a) Grazing food chain and detritus food chain
(b) Production and decomposition
(c) Upright and inverted pyramid.
(d) Food chain and food web
(e) Litter and detritus
(f) Primary and secondary productivity.
Describe the advantages for keeping the ecosystems healthy.
Explain the carbon cycle with the help of a simplified model.
Explain how does:
(a) a primary succession start on a bare rock and reach a climax community?
(b) the algal bloom eventually choke the water body in an industrial area?(a) Explain primary productivity and the factors that influence it.
(b) Describe how do oxygen and chemical composition of detritus control decomposition?
It is often said that the pyramid of energy is always upright. On the other hand, the pyramid of biomass can be both upright and inverted. Explain with the help of examples and sketches.
(a) Explain the significance of ecological pyramids with the help of an example.
(b) Why are the pyramids referred to as upright or inverted?(a) Taking an example of a small pond explain how the four components of an ecosystem function as a unit.
(b) Name the type of food chain that exists in a pond.