The extinction of passenger pigeon was due to

Explanation

**Step-by-Step Solution:**

1. **Introduction to Biodiversity Loss:**
- Biodiversity refers to the variety of life on Earth, including the different species of plants, animals, and microorganisms. It is essential for ecosystem health and stability.

2. **Understanding the Evil Quartet:**
- The "evil quartet" consists of four main reasons for biodiversity loss: habitat loss, overexploitation, invasion of alien species, and co-extinction. Each of these factors contributes to the decline of species populations.

3. **Identifying the Extinction of Passenger Pigeon:**
- The passenger pigeon, scientifically known as Ectopistes migratorius, was once abundant in North America. Its population was so large that it significantly impacted the ecosystem.

4. **Reason for Extinction - Overexploitation:**
- The primary reason for the extinction of the passenger pigeon was overexploitation. Humans hunted these birds extensively for their meat, underestimating their population's vulnerability.

5. **Consequences of Indiscriminate Hunting:**
- As the hunting continued, the population of passenger pigeons declined rapidly. The misconception that their large numbers would ensure their survival led to a lack of conservation efforts.

6. **Final Outcome:**
- Eventually, the passenger pigeon became extinct, illustrating the dramatic impact of human activities on natural ecosystems. The extinction serves as a cautionary tale about the consequences of overexploitation.

7. **Conclusion:**
- The extinction of the passenger pigeon is a clear example of how human actions, particularly overexploitation, can lead to the loss of biodiversity and the extinction of species.

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