Biology (AKU-BIO)
Population: all individuals of one species in an area Community: all populations of different species in an area Ecosystem: community + its physical environment (abiotic factors) Habitat: the place where an organism lives
Arrow shows direction of energy flow (who eats whom) Producers (plants) → Primary consumers → Secondary consumers → Tertiary consumers Decomposers (bacteria, fungi) break down dead material, recycling nutrients
Deforestation: destroys habitat, increases CO₂, causes soil erosion Overfishing: reduces populations, disrupts food webs Pollution: water, air, soil contamination harms organisms
Protected areas (national parks), captive breeding, seed banks Sustainable fishing (catch limits), reforestation
Topic 4 of 7Aga Khan Board
Ecology & Conservation
Food chains, ecosystems, human impact and biodiversity conservation
Ecology studies how organisms interact with each other and their environment.
Key terms:
Food chains and webs:
Grass → Grasshopper → Frog → Snake → Hawk
Energy loss: Only ~10% of energy transfers to the next level (rest lost as heat, excretion, movement). So shorter food chains are more energy-efficient.
Human impact on ecosystems:
Conservation:
Key Points to Remember
- 1Food chain: energy flows from producers to consumers
- 2Only ~10% of energy passes to next trophic level
- 3Deforestation → habitat loss + increased CO₂
- 4Conservation: national parks, captive breeding, sustainable practices
Pakistan Example
Khunjerab National Park — Pakistan's Biodiversity Conservation
Pakistan's Khunjerab National Park protects snow leopards, Marco Polo sheep, and the Indus ecosystem. Deforestation in Khyber Pakhtunkhwa has destroyed habitat for hundreds of species. The WWF Pakistan programme uses captive breeding for the Indus river dolphin — fewer than 2,000 remain. AKU-EB Biology links ecology directly to Pakistan's conservation challenges.