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How Nature Works in Harmony - How Do Interactions Maintain Balance in Nature?

Grade 8CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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An ecosystem consists of biotic (living) and abiotic (non-living) components that interact to maintain a balance, known as ecological equilibrium.

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Food Chains and Food Webs describe the flow of energy and nutrients. A food chain follows a single path: Producer→Primary Consumer→Secondary Consumer→Tertiary Consumer\text{Producer} \rightarrow \text{Primary Consumer} \rightarrow \text{Secondary Consumer} \rightarrow \text{Tertiary Consumer}.

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Trophic Levels: Each step in a food chain is called a trophic level (T1,T2,T3,T4T_1, T_2, T_3, T_4).

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The 10% Rule: Only 10%10\% of the energy available at one trophic level is transferred to the next level; the rest is lost as heat or used for metabolic processes.

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Balance of Gases: Nature maintains the levels of O2O_2 and CO2CO_2 through the processes of photosynthesis and respiration.

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Symbiosis: Interactions like mutualism (both benefit), commensalism (one benefits, other is unaffected), and parasitism (one benefits, other is harmed) help regulate population sizes.

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Decomposition: Decomposers like bacteria and fungi break down dead matter, returning nutrients like nitrogen and phosphorus back to the soil, completing the nutrient cycle.

📐Formulae

6CO2+6H2O→ChlorophyllSunlightC6H12O6+6O26CO_2 + 6H_2O \xrightarrow[Chlorophyll]{Sunlight} C_6H_{12}O_6 + 6O_2

Enext=Ecurrent×10100E_{next} = E_{current} \times \frac{10}{100}

Biomass Transfer Efficiency=(Energy at trophic level nEnergy at trophic level n−1)×100\text{Biomass Transfer Efficiency} = \left( \frac{\text{Energy at trophic level } n}{\text{Energy at trophic level } n-1} \right) \times 100

💡Examples

Problem 1:

In a grassland ecosystem, the plants (producers) capture 20,000 J20,000\text{ J} of solar energy. Calculate the energy available to the snakes (tertiary consumers) in the following food chain: Plant→Grasshopper→Frog→Snake\text{Plant} \rightarrow \text{Grasshopper} \rightarrow \text{Frog} \rightarrow \text{Snake}.

Solution:

  1. Energy at Plant level (T1T_1) = 20,000 J20,000\text{ J}.
  2. Energy at Grasshopper level (T2T_2) = 10% of 20,000=2,000 J10\% \text{ of } 20,000 = 2,000\text{ J}.
  3. Energy at Frog level (T3T_3) = 10% of 2,000=200 J10\% \text{ of } 2,000 = 200\text{ J}.
  4. Energy at Snake level (T4T_4) = 10% of 200=20 J10\% \text{ of } 200 = 20\text{ J}.

Explanation:

According to the 10% Law of energy transfer, only one-tenth of the energy from the previous level is passed to the next level.

Problem 2:

A forest area was originally 850,000 hectares850,000\text{ hectares}. Due to deforestation for urbanization, 123,450 hectares123,450\text{ hectares} were cleared. Calculate the remaining forest area to understand the impact on the local habitat.

Solution:

850000−123450726550\begin{array}{r} 850000 \\ - 123450 \\ \hline 726550 \end{array}

Explanation:

By subtracting the cleared land from the total area, we find the remaining forest is 726,550 hectares726,550\text{ hectares}. Such large-scale reductions disrupt the natural balance and biodiversity.