What are the shortcomings of ecological pyramids in the study of ecosystem?
Ecological pyramids are the graphical representation of ecological parameter. These are characterised by pyramid of number, pyramid of mass and pyramid of energy in an ecosystems. Assumption of a simple food chain is the major shortcoming of ecological pyramids.
If we do not accomode food web, a clear position of or trophic levels of an organisms cannot be given. Saprophytic organism are not given any place in the ecological pyramid, though they are the important component in an ecosystem.
How do you distinguish between humification and mineralisation?
Humification is the process of decomposition of soil that leads to accumulation of a dark-coloured amorphous substance called humus. Humus are highly resistant to microbial action and under goes dicomposition at a very slow rate.
Mineralisation is the process by which the humus is further degraded by microbes and inorganic nutrients or minerals are released back into the substratum.
Fill in the trophic levels ( $1,2,3$ and 4 ) in the boxes provided in the figure.
(i) First trophic level (producers) - Plants
(ii) Second trophic level (primary consumers) - Herbivores
(iii) Third trophic level (secondary consumers) - Carnivores
(iv) Fourth trophic level (tertiary consumers) - Top carnivores
The rate of decomposition of detritus is affected by the abiotic factors like availability of oxygen, pH of the soil substratum, temperature etc. Discuss.
Decomposition of dead remain or matter of animal and plant is carried out by microorganisms like bacteria, fungi etc. The growth rate of these decomposers is affected by abiotic factors like temperature, humidity, pH of soil and light etc.
The soil pH affect the composition of acidophilic and basophilic microorganisms. In absence or presence of oxygen aerobic and anaerobic processes occurs.
In presence of oxygen, complete degradation of substance occureds while in absence of oxygen, there will be an incomplete degradation. Similarly, at high temperature microbes can not grow optimally but high or low temperature favours the growth of stress tolerant microorganisms.
A farmer harvests his crop and expresses his harvest in three different ways.
(a) I have harvested 10 quintals of wheat.
(b) I have harvested 10 quintals of wheat today in one acre of land.
(c) I have harvested 10 quintals of wheat in one acre of land, 6 months after sowing.
Do the above statements mean one and the same thing. If your answer is 'yes', give reasons. And if your answer is 'no' explain the meaning of each expression.
(a) Farmer's expression for his crop harvestation (a) he has harvested 10 quintal of wheat, (b); He has harvested 10 quintals of wheat in one acre of land (c), six, months after sowing mean one and the same thing. Because crop an artificial ecosystem can be prepared with inclusion of bitoic and abiotic component in a given area.
Here abiotic components like water, is given by the farmer, while climatic factor like light, humidity, air is supplied naturally. The living component is wheat plant, which are obtained on harvestation by farmer.