Class 12 Biology Chapter 25 Notes

• Important class 12 biology chapter 25 mcqs for Intermediate part-II students.
• What is ammonification?
• What are root nodules?
• What is a Mycorrhiza? (OR) What are Mycorrhizae?
• What is grazing? How grazing affect the texture of soil? (OR) Define grazing. How grazers affect the ecosystem?
• Important biology class 12 chapter 25 notes for Intermediate part-II students.
• What is biome? (OR) Differentiate between biome and biosphere?
• Briefly write about secondary succession.
• Define predation. (OR) Give the significance of predation. 
• Define succession and name its types.
• Define biogeochemical cycles. (OR) What are biogeochemical cycles?
• Important biology chapter 25 class 12 notes for Intermediate part-II students.
• Define productivity of an ecosystem.
• Define ecosystem. Write its components. (OR) Define ecosystem.
• Define biosphere. (OR) What is biosphere. (OR) Define biosphere and ecosystem.
• Define and describe biotic components of an ecosystem.
• Define commensalism. Give one example. (OR) Define commensalism with the help of an example.  
• Important chapter 25 biology class 12 short questions for Intermediate part-II students.
• Differentiate between population and community.
• Differentiate between habitat and niche. (OR) Define niche. (OR) Explain ecological niche.
• Differentiate between consumers and decomposers. (OR) What are consumers?
• Differentiate between primary and secondary succession. (OR) How primary succession differ from secondary succession? 
• What is nutrient cycle?
• Important class 12 biology chapter 25 important long questions for Intermediate part-II students.

• Define grazing.  Many animals like rabbits, goat, sheep, cow, buffalo and horses feed on grasses. This mode of feeding is called grazing and these animals are called grazers.
• What is autecology?  When one is studying a single population's relationship to its environment it will be called as autecology. For example, we are studying 50 to 100 plants of soyabean for effect of water pollution on their growth and yield, we are studying the single or one population of soyabean plant, this is autecology.
• Important class 12 biology chapter 11 important questions for Intermediate part-II students.
• Define synecology?  Study of relationship of different communities with environment is called synecology or community ecology.
• Differentiate between food chain and food web?  Food chain is a linear relationship of eating and being eaten while food web is the interaction of many food chains.
• Differentiate between primary and secondary succession?  Primary Succession: Succession at a bare rock, sand or clear glacial pool, where there were no race of previous community. It is slow process as soil conditions are not suitable and little nutrients.  Secondary Succession: Succession at a place where there was a previous community but was disturbed as in case of fire. It is relatively fast process as previous community has left its mark in the form of improved soil and seeds.
• Important Ch 11 Biology Class 12 notes for Intermediate part-II students.
• How a predator is related to its prey?  In predator-prey relation, the populations of both the organisms are interrelated. As the population size of prey increases that can support more predators so population of predators also increases. But when the predators increase in number due to rapid predation the size of prey decreases. In this way ecosystem is kept balanced.
• How nitrogen is lost is atmosphere?  The soil nitrogen is converted into atmospheric gaseous nitrogen by a process known as Denitrification. Some denitrifying bacteria in the absence of oxygen break down nitrates back into the atmosphere and using the oxygen for their own respiration.
• Why the process of assimilation is called reverse of nitrification?  In nitrification, ammonium ion is converted into nitrites and nitrates in soil. When these nitrites and nitrates are taken up by plant for assimilation, they convert them back into ammonium ions for further utilization. So both processes are reverse of each other.