Environment and Ecology Mixed Practice — MCQs with Answers (Set 12)

India loses roughly 15,500 square kilometres of natural area each year to fast-spreading invasive species.

Dense Prosopis stands can block access to pasture, firewood, and water, forcing communities to travel farther.

Prosopis juliflora was introduced to combat desertification and supply fuelwood, not planted with malicious intent.

Prosopis juliflora is often mentioned in the news because it tends to reduce biodiversity in the area it grows.

The fertilization effect weakens over time as other nutrients like nitrogen become limiting factors for continued growth.

Crops grown under elevated CO2 often show reduced protein and mineral content, a documented nutritional trade-off.

Elevated CO2 has increased above-ground plant growth by an average of about 21% in controlled studies.

Since CO2 is a raw material for photosynthesis, higher concentrations genuinely increase plant growth rates.

Because a single species causes it, human activity could in principle also reverse the trend, unlike past mass extinctions.

Current extinction rates are estimated at 1,000 to 10,000 times higher than natural background rates.

Unlike the five previous mass extinctions, the sixth is driven by a single species, not a planetary physical process.

The meteorite collision 65 million years ago that killed the dinosaurs caused the fifth mass extinction, not the sixth.

The sixth mass extinction refers to humanity entering an era of unprecedented biodiversity loss due to human activity.

Stromatolites are the most ancient unambiguous fossil record of life on Earth, some dating back 3.7 billion years.

This oxygen buildup, known as the Great Oxidation Event, occurred roughly 2.4 billion years ago.

Early Earth had essentially no free oxygen and was rich in gases like methane and carbon dioxide, not 54% oxygen.

The translocation was delayed by legal disputes and Gujarat’s reluctance, since the state treats the lions as a heritage asset.

Kuno’s current carrying capacity is around 40 lions, though scientists estimate long-term viability needs closer to 80.

India’s Supreme Court ordered the translocation to establish a second wild population and reduce extinction risk.

Junagadh district calls Gir the last remaining abode of the Asiatic lion. The Gujarat Gir site says lions now roam more than 22,000 sq km of Saurashtra. So the wild lions live in and around Gir.

PIB says Kuno-Palpur Sanctuary in Madhya Pradesh was found the most suitable site outside Gir. It was chosen for its area, shape and vegetation. The survey wanted all state governments to accept the plan first.

Rivers may be considered severely polluted when BOD values exceed 8 mg/L, compared to pristine rivers typically below 1 mg/L.

BOD is most commonly measured over 5 days of incubation at 20 degrees Celsius, expressed in milligrams of oxygen per litre.

GCCA’s priority areas include mainstreaming climate into development strategies, adaptation, Disaster Risk Reduction, REDD, and the CDM.

The programme entered a new phase in 2015, rebranding as the Global Climate Change Alliance Plus (GCCA+).