Environment

Answer

✅ D. 1, 2, 3 and 4

Explanation

A Keystone Species has an ecological impact much greater than its population size.

Tiger

• Controls herbivore population.

Sea Otter

• Controls sea urchins.

• Protects kelp forests.

Elephant

• Creates grasslands.

• Disperses seeds.

• Creates water holes.

Honey Bee

• Pollination.

• Supports food production.

Loss of these species destabilizes ecosystems.

UPSC Angle

Differentiate:

• Keystone species

• Umbrella species

• Flagship species

• Indicator species

• Endemic species

Answer

✅ D

Explanation

Norman Myers' criteria:

✔ At least 1500 endemic vascular plants

✔ Lost 70% or more natural vegetation.

India contains:

• Himalaya

• Indo-Burma

• Western Ghats-Sri Lanka

• Sundaland (Nicobar Islands)

Revise

• Endemism

• Biodiversity hotspots

• IUCN

• Biosphere Reserve

• Ramsar Sites

Answer

✅ A

Explanation

Mangroves provide:

• Coastal protection

• Carbon sequestration (Blue Carbon)

• Fish breeding grounds

• Storm buffering

• Livelihood support

The FAO and WFP appealed for $202 million to protect 8.8 million people in 22 high-risk countries from El Niño-related droughts, floods, and storms.

o Why others are incorrect: A, C, and D are not mentioned as the specific drivers for this $202 million funding appeal.

Answer

✅ D

Explanation

All four are invasive alien species that compete with native flora, reduce biodiversity, and alter ecosystem functions.

Statement 1: Correct

To qualify as a biodiversity hotspot, a region must contain at least 1,500 endemic vascular plant species (plants found nowhere else on Earth).

Why important?

• Endemic species are unique to a particular region.

• Their extinction would mean a global loss of biodiversity.

Statement 2: Correct

A biodiversity hotspot must have lost at least 70% of its original natural vegetation/habitat.

Why this criterion?

• Hotspots are not just areas rich in biodiversity; they are also highly threatened.

• Conservation efforts are prioritized in such regions because biodiversity is both rich and vulnerable.

Statement 3: Correct

India is associated with four biodiversity hotspots:

1. Himalaya

2. Western Ghats–Sri Lanka

3. Indo-Burma (includes Northeast India)

4. Sundaland (Nicobar Islands are part of this hotspot)

Therefore, all three statements are correct.

UPSC Trap

UPSC often asks:

"How many biodiversity hotspots are there in India?"

Many candidates answer 3, forgetting that the Nicobar Islands belong to the Sundaland Hotspot. Hence the correct answer is 4.

Answer

✅ D

Explanation

All listed ecosystems absorb and store carbon:

• Forests: biomass and soils

• Oceans: dissolved carbon and marine biota

• Peatlands: organic-rich soils

• Mangroves: highly efficient "blue carbon" ecosystems

Statement 1: Correct

Genetic diversity refers to the variation in genes among individuals of the same species.

Example:

Humans belong to one species, yet individuals differ in:

• Height

• Skin color

• Eye color

• Disease resistance

Similarly, different varieties of rice, wheat, or mangoes show genetic diversity.

Importance:

• Helps species adapt to environmental changes.

• Increases resistance to diseases and pests.

• Enhances survival and evolution.

Therefore, Statement 1 is correct.

Statement 2: Correct

Species diversity is measured through two components:

(a) Species Richness

The number of different species present in an area.

Example:

• Forest A has 100 species.

• Forest B has 50 species.

Forest A has greater species richness.

(b) Species Evenness

How evenly individuals are distributed among those species.

Example:

• If one species dominates 95% of the population, evenness is low.

• If all species have similar populations, evenness is high.

Species diversity depends on both richness and evenness.

Therefore, Statement 2 is correct.

Statement 3: Incorrect

Ecosystem diversity refers to the variety of ecosystems in a region.

It includes:

• Forests

• Grasslands

• Deserts

• Wetlands

• Rivers

• Lakes

• Marine ecosystems

Thus, ecosystem diversity includes both terrestrial and aquatic ecosystems, not only terrestrial ecosystems.

Therefore, Statement 3 is incorrect.

The main drivers of biodiversity loss are often summarized as:

"The Evil Quartet" (classic ecology)

1. Habitat loss and fragmentation

2. Overexploitation

3. Invasive alien species

4. Co-extinctions

Modern environmental reports additionally emphasize:
5. Climate change
6. Pollution