NCERT Solutions for Class 12 Biology Chapter 14
NCERT Solutions for Class 12 Biology Chapter 14 Ecosystem to Study Online or download in PDF file format updated for new academic session 2020-21 following the latest CBSE Curriculum 2020-2021.
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NCERT Solutions for Class 12 Biology Chapter 14
Class: | 12 |
Subject: | Biology |
Chapter 14: | Ecosystem |
Class 12 Biology Chapter 14 Solutions in English
NCERT Solutions for Class 12 Biology Chapter 14 is given here to download in PDF format free. NCERT Solutions 2020-21 and Offline Apps based on these solutions are updated for new academic session 2020-21. Download NCERT Books 2020-21 based on latest CBSE Syllabus 2020-2021. Ask your doubts through Discussion Forum and answer the questions asked by other users.
Important Terms related to Chapter 14
1. Ecosystem: It is the basic functional unit of biosphere in which living organisms interact among themselves and with their surrounding physical environment.
2. Detritus: Dead leaves, twigs, animal remains etc. constitute detritus.
Ecological succession: The successive and orderly replacement of one community by the other community in an area, over a period of time.
Stratification
Vertical distribution of different species occupying different levels in an ecosystem. Trees occupy top vertical strata, shrubs the second layer and herbs the third layer and herbs/grasses occupy the bottom layers.
1. Primary Production: Amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis.
2. Detritus: Dead leaves, twigs, animal remains etc. constitute detritus.
3. Detrivore: Organisms who break down detritus into smaller particles, e.g., earthworm.
4. Process of Decomposition: The decomposers break down complex organic matter into inorganic substances like carbon dioxide, water and nutrients. This process is called decomposition.
Productivity
1. Gross Primary Productivity: Rate of production of organic matter during photosynthesis.
2. Net Primary Productivity: NPP = GPP-R (Gross primary productivity minus the respiration losses).
3. Secondary Productivity: Rate of formation of new organic matter by consumers.
4. Climax community: The stable and final biotic community that develops at the end of ecological succession and is in perfect harmony with its physical environment.
5. Food Web: A number of food chains interconnected with each other forming a web-like pattern.
10 % Law of Energy Transfer
Ten percent law of energy transfer proposed by Lindeman. At each step of food chain, when energy is transferred from one tropic level to the next tropic level, only 10 percent of energy is passed on to the next trophic level.
Factors affecting decomposition
Decomposition is controlled by:
Chemical composition of detritus: The decomposition will slower if detritus is rich in lignin and chitin and will faster if detritus is rich in nitrogen and water soluble substance (sugar).
Climatic factors: In warm and moist environment, the process of decomposition increases whereas low temperature and anaerobiosis inhibit the decomposition.
Important Questions on 12th Biology Chapter 14
The two components of an ecosystem are:
Biotic component: It is the living component of an ecosystem that includes biotic factors such as producers, consumers, decomposers, etc. Producers include plants and algae. They contain chlorophyll pigment, which helps them carry out the process of photosynthesis in the presence of light. Thus, they are also called converters or transducers. Consumers or heterotrophs are organisms that are directly (primary consumers) or indirectly (secondary and tertiary consumers) dependent on producers for their food.
Decomposers include micro-organisms such as bacteria and fungi. They form the largest population in a food chain and obtain nutrients by breaking down the remains of dead plants and animals.
There are three types of pyramids:
Pyramid of numbers
Pyramid of energy
Pyramid of biomass
Primary productivity of an ecosystem depends on the variety of environmental factors such as light, temperature, water, precipitation, etc. It also depends on the availability of nutrients and the availability of plants to carry out photosynthesis.
Sedimentary cycles are very slow. They take a long time to complete their circulation and are considered as less perfect cycles. This is because during recycling, nutrient elements may get locked in the reservoir pool, thereby taking a very long time to come out and continue circulation. Thus, it usually goes out of circulation for a long time.