Ecosystems are communities of living organisms interacting with their environment. They are mainly of two types:
- Aquatic Ecosystems – Lakes, rivers, and oceans. Plants here use CO₂ and produce oxygen through photosynthesis. Humans can affect these ecosystems.
- Terrestrial Ecosystems – Forests, grasslands, deserts, and tundra. Each has unique plants, animals, and climate.
In Pakistan, ecosystems vary from hot plains to snowy mountains. Major types include temperate forests, coniferous forests, grasslands, deserts, and tundra.
This unit helps you understand these ecosystems, their features, and human impact on them.
📥 Download Class 12 Biology Unit 26 – Some Major Ecosystems
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👉 Download PDF: Class 12 Biology Unit 26 – Some Major Ecosystems
❓FAQ – Class 12 Biology Unit 26
1. What is an ecosystem?
An ecosystem is a community of living organisms interacting with each other and their physical environment.
2. What are the main types of ecosystems?
There are two main types:
- Aquatic (Hydrospheric) Ecosystems – lakes, rivers, oceans
- Terrestrial (Lithospheric) Ecosystems – forests, grasslands, deserts, tundra
3. Which are the major ecosystems in Pakistan?
Temperate deciduous forests, coniferous alpine and boreal forests, grasslands, deserts, and tundra.
4. How is productivity measured in aquatic ecosystems?
Productivity is measured by the amount of CO₂ consumed and oxygen produced during photosynthesis.
5. How do humans affect ecosystems?
Human activities like deforestation, pollution, and overfishing can disturb ecosystem balance and reduce biodiversity.
📝 MCQs – Some Major Ecosystems
1. Which of the following is a terrestrial ecosystem in Pakistan?
A) Lake Saif-ul-Malook
B) Temperate deciduous forest
C) Arabian Sea
D) Indus River
Answer: B) Temperate deciduous forest
2. Productivity in aquatic ecosystems is mainly measured by:
A) Number of fish
B) CO₂ consumption and O₂ production
C) Rainfall amount
D) Soil type
Answer: B) CO₂ consumption and O₂ production
3. Where are coniferous alpine and boreal forests found in Pakistan?
A) Neelam Valley and Shogran
B) Kaghan, Malam Jabba, Dir, Chilas
C) Gilgit and Kashmir
D) Bahawalpur and Yazman
Answer: B) Kaghan, Malam Jabba, Dir, Chilas
4. Which ecosystem has mostly treeless regions and is found at high latitudes or altitudes?
A) Desert
B) Grassland
C) Tundra
D) Temperate forest
Answer: C) Tundra
5. Grasslands in tropical climates are called:
A) Prairies
B) Savanna
C) Taiga
D) Tundra
Answer: B) Savanna