FAQs on Basics of Ecology

Question 1

1. What exactly is an ecosystem and how does it differ from a community in ecology?

Accepted Answer

Ans. An ecosystem comprises living organisms (community) plus their non-living physical environment like soil, water, and climate working together as an integrated unit. A community refers only to the interacting populations of different species in an area. Ecosystems emphasise energy flow and nutrient cycling across biotic and abiotic components, making them broader functional systems compared to communities.

Question 2

2. Why do energy pyramids always have fewer organisms at the top trophic level?

Accepted Answer

Ans. Energy pyramids narrow towards apex levels because only about 10% of energy transfers between consecutive trophic levels; the remaining 90% is lost through respiration, movement, and heat. Primary consumers receive less energy from producers than producers capture from the sun. This progressive energy loss means top carnivores require enormous producer biomass to sustain themselves, naturally resulting in fewer individuals at higher trophic levels.

Question 3

3. How do succession and ecological succession actually change a bare habitat over time?

Accepted Answer

Ans. Ecological succession is the gradual, predictable replacement of communities in an area over decades or centuries. Primary succession begins on barren ground where pioneer species like lichens colonise rock, weather it into soil, and die to enrich it. Secondary succession occurs in disturbed but soil-rich areas, progressing faster than primary succession. Both processes eventually stabilise into a climax community representing the area's maximum biodiversity and stability for given environmental conditions.

Question 4

4. What's the difference between parasitism and predation when both involve one organism harming another?

Accepted Answer

Ans. Predation involves one organism (predator) killing and consuming another (prey), benefiting the predator while harming prey populations through direct mortality. Parasitism features a smaller parasite living on or inside a larger host, gradually weakening it without immediate killing. Predators are typically larger and mobile; parasites are smaller and depend on hosts for survival. Both are symbiotic relationships, but parasites maintain longer-term associations with hosts compared to one-time predator-prey encounters.

Question 5

5. How do biodiversity and ecosystem stability actually relate to each other in nature?

Accepted Answer

Ans. Greater biodiversity increases ecosystem stability because diverse species populations provide functional redundancy-if one species declines, others perform similar ecological roles, maintaining ecosystem processes. Biodiverse ecosystems better withstand environmental disturbances, diseases, and resource fluctuations through varied food webs and nutrient cycling pathways. Species richness creates complex interdependencies that buffer ecosystems against collapse, making biodiversity a critical indicator of ecosystem resilience and long-term productivity in natural habitats.

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