Few problems along with their solutions from this chapter are given follows:
Q. An inverted pyramid of biomass can be found in which ecosystem?
(a) Forest (b) Marine (c) Grass land (d) Tundra
Ans. (b) Marine
In case of aquatic ecosystem like pond ecosystem, marine ecosystem, pyramid of biomass is inverted because the biomass of fishes exceeds than that of phytoplanktons which make the small standing crop of aquatic ecosystems.
In aquatic ecosystem biomass of trophic level depends upon reproductive potential and longevity of its members
Q. Primary productivity varies from ecosystem to ecosystem. Explain?
Ans. Primary productivity is the rate at which primary producers (plants) capture and store solar radiation to form chemical energy. Primary production depends upon producers (green plant) which are variable in different ecosystems. So, primary productivity varies from ecosystem to ecosystem.
Q. How do you distinguish between humification and mineralisation?
Ans. Humification is the process of decomposition of soil that leads to accumulation of a dark-coloured amorphous substance called humus. Humus is 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.
Q. What will happen to an ecosystem if
(a) All producers are removed?
(b) All organisms of herbivore Level are eliminated and?
(c) All top carnivore population is removed?
Ans. (a) Removal of all producers reduces primary production in the ecosystem. Hence, no biomass will be available to the successive/higher trophic level or heterotrophic organisms.
(b) Elimination of all organisms of herbivore level results into an increase in primary productivity and biomass of producer and carnivorous animal will not survive due to unavailability of food herbivores.
(c) Removal of top carnivores also disturb the ecosystem as it will result in huge increase in number of herbivores which will finish plants (producers) creating desertification.
Class 12 Biology NCERT Exemplar Problems:
The NCERT Exemplar problems are considered to be the most applicative kind of problems which help to enhance a student’s critical thinking and problem solving ability. These problems form the best practice source to prepare effectively for board exams and the medical entrance tests. So, it’s very important for students to practice the NCERT exemplar problems to prepare well for the boards and the competitive exams.
Here, we are providing the NCERT Exemplar Problems for Class 12 Biology chapter - Ecosystem, in the PDF form which students may download and solve them to analyse their preparedness for the exams.
Main topics discussed in Class 12 Biology, Chapter 14- Ecosystem, are:
- Ecosystem–Structure and Function
- Productivity
- Decomposition
- Energy Flow
- Ecological Pyramids
- Ecological Succession
- Nutrient Cycling
- Ecosystem Services