Biodiversity: UPSC Previous Year Questions (Environment and Ecology)
2 previous year UPSC Prelims questions on Biodiversity (Environment and Ecology). Choose an option to see the answer and explanation.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 1–2 of 2 questions
UPSC 2021Environment and Ecology · Biodiversity
Q1. Which one of the following is used in preparing a natural mosquito repellent?
Explanation
Lemongrass is a tall herb that is widely distributed in tropical and subtropical regions of Asia, Africa, and Australia. Lemongrass is most frequently produced in China and India. The lemongrass herb is well known for its effectiveness at warding off mosquitoes and works as a mosquito repellent. It contains the chemical citronella, which aids in disguising the smells that mosquitoes use to target victims. A 2011 study found that the strong odour of lemongrass oil effectively killed or fully repelled more than 90% of the mosquitoes from a particular range of species.
UPSC 2021Environment and Ecology · Biodiversity
Q2. The vegetation of savannah consists of grassland with scattered small trees, but extensive areas have no trees. The forest development in such areas is generally kept in check by one or more or a combination of some conditions. Which of the following are such conditions? 1. Burrowing animals and termites 2. Fire 3. Grazing herbivores 4. Seasonal rainfall 5. Soil properties Select the correct answer using the code given below.
Explanation
Savanna Biome is a particular kind of grassland biome made up of vast expanses of open grassland with few trees. Tropical and Semi-tropical savannas are two kinds of savannas. All continents excluding Antarctica have grasslands. The largest savannas are found close to the equator in Africa.
Option (c) is correct:
Frequent wildfires both natural (lightning-induced) and human-induced prevent the establishment of dense forests. Fires destroy young tree saplings before they can mature into large trees, thus maintaining grasslands. Savanna fires are a key ecological process that helps maintain the balance between grasslands and scattered trees. Large herbivores like elephants, zebras, and antelopes feed on young tree shoots, preventing forests from expanding. Grazing by animals ensures that tree cover remains sparse which allows grasses to dominate. Studies on African and Indian savannas have shown that herbivory is a critical limiting factor for tree growth. The limited and unpredictable rainfall pattern allows grasses to outcompete trees for available water. Savannas experience distinct wet and dry seasons leading to limited water availability. Trees require consistent moisture to grow into dense forests but in savannas prolonged dry periods hinder tree survival. Burrowing animals such as aardvarks and rodents and termites play a role in soil aeration and nutrient cycling. But they do not significantly prevent tree growth or forest development. Trees can grow in varied soil types and soil properties alone do not explain forest suppression.
Exam tip:
For S2, Dry grasses = natural fuel Fires regularly kill saplings, preventing tree establishment. Strong YES -- fire is a well-known forest-suppressing factor(observed logic too), this itself eliminates option B and D. Similar is grazing animals(S3), Prevent trees from maturing. Clearly a suppressing factor(again observed logic)
Answer key for these questions
Q
UPSC year
Correct answer
1
2021
(c) Lemongrass
2
2021
(c) 2, 3 and 4
Frequently asked questions
How many previous year UPSC questions are there on Biodiversity?
This page covers 2 previous year UPSC Prelims GS Paper-I questions on Biodiversity (Environment and Ecology), asked from 2003 to 2024. Each has the correct answer and an explanation.
How should I use previous year UPSC questions for Prelims?
Attempt each question first, then open the answer and read the explanation for every option. Repeat by chapter, and track which statements UPSC reuses across years. Previous year questions show the exam pattern and difficulty level.
Which years are covered for Biodiversity?
Questions on Biodiversity (Environment and Ecology) are available for 10 years, from 2003 to 2024. Use the Year filter to practise a single paper.
