CTET EVS: Pollution, Malaria & Bird Nesting Habits
This part of the NCERT series focuses on environmental challenges and the fascinating world of birds and their nesting habits.
🌫️ Environmental Pollution
1. Air Pollution
- Causes: Dust, industrial emissions, automobile exhaust, and smoke.
- Major Factors: Population explosion and rapid industrialization.
- Control: Use of scrubbers, electrostatic precipitators, and cleaner fuels (like CNG).
2. Water Pollution
- Physical: Industrial hot water, oil spills.
- Chemical: Organic biocides, phosphates, nitrates, and heavy metals.
- Biological: Pathogens like viruses, bacteria, and algae.
🧪 Diseases Related to Pollution
- Contaminated Water: Jaundice, Cholera, and Typhoid.
- Minamata Disease: Caused by Mercury poisoning (first identified in Japan).
- Itai-Itai Disease: Caused by Cadmium pollution (affects liver and lungs).
🦟 Malaria: Discovery & Cure
Malaria is a recurring topic in EVS pedagogy due to its scientific history.
- Discovery: Ronald Ross discovered that malaria is spread by mosquitoes. He received the Nobel Prize in 1905.
- Vector: Caused by the Female Anopheles mosquito.
- Treatment: The dried and powdered bark of the Cinchona tree is used to make medicine (Quinine).
🐦 Birds and their Nests (पक्षियों के घोंसले)
Birds have unique nesting habits that are frequently tested in the CTET exam.
| Bird | Nesting Habit |
|---|---|
| Indian Robin | Lays eggs between stones along the roadside. Nest made of twigs, wool, and cotton. |
| Crow | Builds its nest high up on a tree using wire, wood, and twigs. |
| Koel | Does not build its own nest. It lays eggs in a crow's nest, and the crow hatches them. |
| Dove (फ़ाख्ता) | Makes its nest among the thorns of a cactus or a mehendi hedge. |
| Sparrow/Pigeon | Often build nests in and around houses (cupboards, mirrors, old buildings). |
| Tailor Bird | Stitches two leaves together with its sharp beak to create a pouch for eggs. |
| Sunbird | Makes a nest that hangs from the branch of a small tree or bush. |
| Weaver Bird | Male weaver birds make beautiful woven nests. The female chooses the best one. |
ℹ️ Note
The Weaver Bird Strategy: The female weaver bird inspects all the nests built by the males and decides which one to use for laying eggs based on quality and safety.