Q1.
What happens when we intervene in nature?
Answer
One change sets off a chain of others, and the last link is usually back on us. Activity 12.9 gives a real Indian example.
1980s: large-scale export of frog legs (Indian bullfrog, Hoplobatrachus tigerinus)
→ decline in frog populations
→ frogs eat insects, so agricultural pests rose
→ farmers forced to use more synthetic pesticides
→ harm to environment, soil and water quality
→ effects on overall environmental and human health
→ decline in frog populations
→ frogs eat insects, so agricultural pests rose
→ farmers forced to use more synthetic pesticides
→ harm to environment, soil and water quality
→ effects on overall environmental and human health
The Government of India banned the export of frog legs to prevent further ecological damage.
Fig. 12.13 shows the same shape of chain in a pond: plants die because of pollution → less oxygen is produced in the water → the fish population drops → with fewer consumers, insects increase → the insects spread to nearby farmland → farmers are compelled to use pesticides, which again affect the environment.
Why it happens: an ecosystem stays in balance when interactions among organisms and their environment keep populations and resources stable. That balance is dynamic, not fixed. Removing one population removes several interactions at once, so the numbers above and below it move — and each of those movements starts a further one. The frogs were being taken for a reason that had nothing to do with farming, yet the cost landed on farmers.