🌿 INTRODUCTION

Biota and Environment is a major topic in ecology that explains the relationship between living organisms (biota) and their physical surroundings (environment). It helps us understand how ecosystems function, how energy flows, and how different organisms depend on each other for survival.

This chapter includes important concepts like ecosystem structure, food chains, food webs, ecological pyramids, energy flow, and nutrient cycling. It also covers environmental issues such as pollution, global warming, ozone depletion, acid rain, and conservation of natural resources.

For competitive exams, this chapter is very important because most questions are concept-based and logic-driven. Understanding the basic principles is more important than memorization.

---

⚡ Quick Revision Notes (Complete Chapter)

🌍 Ecosystem: A functional unit of nature where living organisms interact with each other and with the environment.

🌱 Components of Ecosystem:

• Biotic (producers, consumers, decomposers)

• Abiotic (light, temperature, water, soil, air)

🍃 Producers: Green plants and algae that prepare food using photosynthesis.

🦌 Consumers:

• Primary: Herbivores (deer, rabbit)

• Secondary: Carnivores (frog, snake)

• Tertiary: Top carnivores (lion, eagle)

🍂 Decomposers: Bacteria and fungi that break down dead matter.

🔗 Food Chain: Linear sequence of energy transfer.
🌐 Food Web: Interconnected food chains.

⚡ Energy Flow: Unidirectional and follows 10% law.

📊 Ecological Pyramids:

• Pyramid of number

• Pyramid of biomass

• Pyramid of energy (always upright)

🌳 Biodiversity: Greatest in tropical rainforests due to stable climate.

☀️ Ozone Layer: Protects Earth from harmful UV radiation.

🌫️ Greenhouse Gases: CO₂, CH₄, N₂O cause global warming.

☠️ Biomagnification: Increase in toxic substances at higher trophic levels.

🌊 Eutrophication: Excess nutrients in water → algae bloom → oxygen depletion.

🌧️ Acid Rain: Caused by SO₂ and NO₂ reacting with water vapor.

🌿 Lichens: Bioindicators of air pollution.

⛏️ Natural Resources:

• Renewable: Solar, wind, water

• Non-renewable: Coal, petroleum

🌳 Deforestation Effects: Soil erosion, biodiversity loss, climate change.

🔄 Nitrogen Cycle: Nitrogen fixation → nitrification → assimilation → denitrification.

🌎 Environmental Conservation: Protection and sustainable use of natural resources.

---

🚀 TEST INSTRUCTIONS (IMPORTANT)

📌 This is a CEE-level MCQ practice test.

🧠 Read each question carefully before answering.

🎯 Each question has only one correct answer.

⏱️ Focus on accuracy first, then speed. Do not rush.

❌ Avoid random guessing — try to apply concepts.

📊 After submitting, check your score and identify weak areas.

🔁 Revise the notes again if your score is low and retake the test for improvement.

💪 Treat this as a real exam practice session for better performance.

 

BIOTA & ENVIRONMENT CEE PREP

1. Which biome has highest biodiversity?

Desert Tundra Tropical rainforest Grassland

2. Which is a primary consumer?

Lion Deer Hawk Snake

3. Energy transfer follows?

100% law 50% law 10% law 1% law

4. Ozone layer protects from?

Infrared UV rays Visible light X-rays

5. Which is greenhouse gas?

O₂ CO₂ N₂ He

6. Biomagnification increases at?

Lower trophic level Middle Higher trophic level Same

7. Producers are?

Carnivores Herbivores Plants Decomposers

8. Which cycle involves nitrogen fixation?

Carbon cycle Nitrogen cycle Water cycle Oxygen cycle

9. Which causes acid rain?

CO₂ SO₂ O₂ H₂

10. Ecological pyramid always upright for?

Biomass Energy Numbers None

11. Lichens indicate?

Water pollution Air pollution Soil fertility Climate

12. Which is non-renewable resource?

Solar Wind Coal Water

13. Eutrophication caused by?

Nutrient excess Oxygen increase Less algae Low nutrients

14. Which is keystone species?

Rare species Dominant species Species with large impact Extinct species

15. Deforestation leads to?

Soil erosion Biodiversity loss Climate change All of these

📲 Join WhatsApp Channel