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) Pioneer species is the species of organism that invades the bare area. Lichens usually are the pioneer species on a bare rock. They secrete acids which dissolve rocks, thereby leading to weathering of rocks and soil formation. This paves the way for small plants like bryophytes which are able to take hold in the small amount of soil. They are succeeded by bigger plants, several more stages, and ultimately by a stable climax forest community which remains stable as long as the environment remains unchanged.
(b) Algal bloom is the excessive growth of the free-floating (planktonic ) in the water bodies , due to the presence of large amount of nutrients in the water. Water bodies in the industrial area have excess of nutrients which in turn promotes algal bloom. The algal bloom imparts a distinct colour to the water bodies and also robs the water of dissolved oxygen that is vital to aquatic organisms. They cause deterioration of the water quality and also produce toxins which are harmful to other organisms. The other pollutants flowing into the lake further decrease the oxygen levels in the water and poison the lake. Thus algal bloom can literally choke the lake to death.
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.
(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.
Discuss the role of healthy ecosystem services as a prerequisite for a wide range of economic, environmental and aesthetic goods and services.