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Chapter 14 of 15
Revision Notes

Ecosystems and Energy Flow

Maharashtra Board · Class 12 · Biology

Quick revision notes for Ecosystems and Energy Flow — Maharashtra Board Class 12 Biology. Key concepts, formulas, and definitions for last-minute revision.

45 questions25 flashcards5 concepts

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Key Topics to Revise

1

14.1 Ecosystem Structure and Function

  • Ecosystem coined by Tansley (1935) - includes biotic and abiotic components in interaction
  • Classification: Natural ecosystems (self-sustaining) vs Artificial ecosystems (require human input)
  • Terrestrial ecosystems: Forest, grassland, desert
2

14.2 Energy Flow in Ecosystems

  • Sun is the ultimate source of energy for all ecosystems (except deep-sea ecosystems)
  • Only <50% of solar radiation is Photosynthetically Active Radiation (PAR)
  • Plants capture only 2-10% of PAR - this sustains the entire living world
3

14.3 Ecological Pyramids

  • Ecological pyramids represent relationships between organisms at different trophic levels
  • Concept developed by Charles Elton (1927)
  • Three types: Pyramid of Numbers, Pyramid of Biomass, Pyramid of Energy
4

14.4 Biogeochemical Cycles

  • Nutrients are recycled indefinitely in ecosystems - never lost
  • Two types: Gaseous cycles (reservoir = atmosphere) and Sedimentary cycles (reservoir = Earth's crust)
  • Carbon Cycle: 71% of global carbon in oceans, 49% of organism dry weight is carbon

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Full Notes

Key Concepts

Ecosystems show spatial patterns like stratificationPrimary productivity measures the rateDecomposition breaks down dead organic matterEnergy flows unidirectionally from sunEcological pyramids represent trophic relationships graph...

Frequently Asked Questions

What are the important topics in Ecosystems and Energy Flow for Maharashtra Board Class 12 Biology?
Ecosystems and Energy Flow covers several key topics that are frequently asked in Maharashtra Board Class 12 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in Ecosystems and Energy Flow — Maharashtra Board Class 12 Biology?
Understand the core concepts first, then work through the 45 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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