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How Nature Works in Harmony - What Are the Different Types of Interactions in Nature?

Grade 8CBSE

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

🔑Concepts

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Ecosystem: A functional unit of nature where living organisms (biotic factors) interact among themselves and with the physical environment (abiotic factors like sunlight, H2OH_{2}O, and soil).

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Mutualism: A type of interaction where both species benefit from each other (+/+)(+/+). Example: Lichens, where fungi provide shelter and algae provide food.

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Commensalism: An interaction where one species benefits while the other is neither harmed nor benefited (+/0)(+/0). Example: An orchid growing on a mango branch.

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Parasitism: A relationship where one species (parasite) benefits by living on or inside another species (host), usually harming the host (+/−)(+/-). Example: Cuscuta (Amarbel) on garden plants.

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Predation: A biological interaction where one organism, the predator, kills and eats another organism, its prey. This helps in maintaining the population balance.

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Competition: An interaction where both species are harmed (−/−)(-/-) as they compete for the same limited resources like food, water, or territory.

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The 10% Law of Energy Transfer: In a food chain, only 10%10\% of the energy available at a trophic level is transferred to the next higher level.

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Photosynthesis: The process by which green plants (producers) convert light energy into chemical energy, represented by the chemical equation 6CO2+6H2O→C6H12O6+6O26CO_{2} + 6H_{2}O \rightarrow C_{6}H_{12}O_{6} + 6O_{2}.

📐Formulae

Energyavailable to next level=10%×Energycurrent levelEnergy_{available\ to\ next\ level} = 10\% \times Energy_{current\ level}

6CO2+6H2O→Sunlight/ChlorophyllC6H12O6+6O26CO_{2} + 6H_{2}O \xrightarrow{Sunlight/Chlorophyll} C_{6}H_{12}O_{6} + 6O_{2}

Net Primary Productivity=Gross Primary Productivity−Respiration lossesNet\ Primary\ Productivity = Gross\ Primary\ Productivity - Respiration\ losses

💡Examples

Problem 1:

In a food chain consisting of Grass →\rightarrow Deer →\rightarrow Lion, if the Grass produces 20,000 J20,000\text{ J} of energy, calculate the energy available to the Lion.

Solution:

  1. Energy at Producer level (Grass) = 20,000 J20,000\text{ J}.
  2. Energy at Primary Consumer level (Deer) = 10% of 20,000=2,000 J10\% \text{ of } 20,000 = 2,000\text{ J}.
  3. Energy at Secondary Consumer level (Lion) = 10% of 2,000=200 J10\% \text{ of } 2,000 = 200\text{ J}.

20000×0.102000\begin{array}{r} 20000 \\ \times 0.10 \\ \hline 2000 \end{array} 2000×0.10200\begin{array}{r} 2000 \\ \times 0.10 \\ \hline 200 \end{array}

Explanation:

According to the 10% Law, only one-tenth of the energy is transferred to each subsequent trophic level, while the rest is lost as heat to the environment during metabolic activities.

Problem 2:

Identify the type of interaction: A tick living on the skin of a dog and sucking its blood.

Solution:

This is an example of Parasitism (+/−)(+/-).

Explanation:

In this interaction, the tick (parasite) derives nutrition and benefit, whereas the dog (host) is harmed by the loss of blood and potential diseases.