Class 12 Biology - BIHAR
Ecosystem
The 'Ecosystem' chapter in Class 12 Biology explores the functional units of nature where living organisms interact among themselves and with their physical environment. For Bihar Board (BSEB) students, this chapter is crucial as it forms a major part of the Ecology unit. You will learn about ecosystem structure and function, productivity, decomposition, energy flow through trophic levels, ecological pyramids, and nutrient cycling like carbon and phosphorus cycles. Ecological succession and ecosystem services are also highlighted. Mastering this chapter helps you score high in board exams through conceptual questions, diagram-based problems, and differentiation tasks.
Start Learning FreeKey Concepts
Productivity
The rate of biomass production, divided into Gross Primary Productivity (GPP) and Net Primary Productivity (NPP), which is available to consumers.
Decomposition
The breakdown of complex organic matter into inorganic substances like carbon dioxide, water, and nutrients through steps like fragmentation, leaching, catabolism, humification, and mineralization.
Energy Flow
The unidirectional movement of energy through trophic levels in an ecosystem, governed by the 10% law of energy transfer.
Ecological Pyramids
Graphical representations of trophic structure parameters such as number, biomass, and energy across successive trophic levels.
Ecological Succession
The predictable and gradual change in the species composition of a given area over time, leading to a stable climax community.
Nutrient Cycling
The movement of nutrient elements through the biotic and abiotic components of an ecosystem, also known as biogeochemical cycles.
Important Formulas
Board Exam Info
In the Bihar Board (BSEB) Class 12 Biology exam, the Ecology unit carries around 14-16 marks, with the 'Ecosystem' chapter contributing significantly. Expect 1-2 objective (MCQ) questions, short-answer questions defining ecological terms or pyramids, and occasionally a long-answer question on energy flow or ecological succession.
Frequently Asked Questions
What is the difference between GPP and NPP?
GPP is the total rate of biomass production during photosynthesis, whereas NPP is the remaining biomass after plant respiration losses (NPP = GPP - R).
Why is the pyramid of energy always upright?
The pyramid of energy is always upright because energy is lost as heat at each trophic level during transfer, according to the 10% law.
What is the difference between primary and secondary succession?
Primary succession starts in areas where no living organisms ever existed (like bare rock), while secondary succession begins in areas where natural life was destroyed (like a burnt forest).
Learn Ecosystem with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards