Activity 12.3: Pond A vs. Pond B
Observation:
- Pond A (With Fish): Fewer dragonflies, MORE bees/butterflies, MORE flowers/seeds.
- Pond B (No Fish): Many dragonflies, FEWER bees/butterflies, FEWER flowers/seeds.
Analysis of the Chain:
- Fish eat Dragonfly larvae: Fish act as a regulator.
- Dragonflies eat Pollinators: Dragonflies are predators of bees and butterflies.
- Pollinators help Plants: Bees/Butterflies are essential for plant reproduction (seeds).
Conclusion: The presence of fish indirectly helps the plants on the land nearby! This proves that aquatic ecosystems (pond) and terrestrial ecosystems (land plants) are interconnected.
Activity 12.7: The Pyramid of Numbers
Scenario: A crop field.
- Base: Millets (Thousands of plants) - Producers.
- Middle: Mice (Hundreds) - Primary Consumers.
- Top: Eagle (One or two) - Tertiary Consumer.
Why a Pyramid? There are always more producers than consumers. Energy is lost at each step (the mouse uses energy to run, keep warm, etc., so the eagle gets less energy than the mouse ate). Therefore, the ecosystem can support fewer top predators than herbivores.
Activity 12.10: Farm Survey
Key Findings from Sustainable Farmers:
- Vermicomposting: Using earthworms to turn waste into manure.
- Neem Spray: Using natural neem solutions instead of chemical pesticides to repel insects.
- Mixed Cropping: Growing pulses (dal) with cereals. Pulses fix nitrogen in the soil naturally, reducing the need for urea fertilizers.
Tip
Project Idea: Create a “Biodiversity Log” for a tree near your house. Note down:
- Who eats the leaves? (Caterpillars/Beetles)
- Who lives in the bark? (Ants/Spiders)
- Who visits the flowers? (Bees/Sunbirds)
- Who sits on the branches? (Crows/Squirrels) You will realize a single tree is an entire Ecosystem!