Ecology & Environment – UGC NET – Geography – Solved PYQs

1. Match the List-I with List-II and select the correct answer from the codes given below. (SEPT 2013)

List-I (Natural Vegetation) | List-II (Indian States / UTs)
A. Conifers — I. Jharkhand
B. Evergreen — II. Rajasthan
C. Xerophytes — III. Andaman & Nicobar
D. Deciduous — IV. Jammu & Kashmir

Codes

A | B | C | D

(1) III | IV | I | II
(2) IV | III | II | I
(3) II | I | III | IV
(4) I | II | IV | III

Correct Answer: (2) IV – III – II – I

Explanation:

The distribution of natural vegetation in India is closely related to climatic conditions, rainfall, temperature, altitude, and soil characteristics. Different regions of the country support different types of vegetation according to their environmental conditions.

Coniferous forests are mainly found in the Himalayan region where temperatures are low and altitudes are high. Trees such as pine, deodar, fir, spruce, and cedar dominate these forests. In India, Jammu & Kashmir is one of the most important regions where coniferous vegetation is extensively developed. Therefore, A matches with IV.

Evergreen forests occur in areas receiving very high rainfall throughout the year. These forests remain green in all seasons because trees do not shed their leaves simultaneously. The Andaman & Nicobar Islands experience heavy rainfall and a humid tropical climate, making them a major region of tropical evergreen forests. Therefore, B matches with III.

Xerophytic vegetation is adapted to dry and arid conditions. Plants such as cactus, acacia, and thorny shrubs have special features to conserve water. Such vegetation is characteristic of the desert and semi-desert regions of Rajasthan, especially the Thar Desert. Therefore, C matches with II.

Deciduous forests, also known as monsoon forests, are the most widespread forest type in India. These forests shed their leaves during the dry season to reduce water loss. States receiving moderate rainfall support this vegetation. Jharkhand is well known for its extensive tropical deciduous forests dominated by sal, teak, bamboo, and other species. Therefore, D matches with I.

The correct matching is A–IV, B–III, C–II, D–I, which corresponds to Option (2).

2. Vast numbers of herbivorous animals and carnivorous such as lions, jackals and hyenas are found in (JUNE 2014)

(1) Equatorial rainforest
(2) Taiga
(3) Campos of Brazil
(4) Savannas of Africa

Correct Answer: (4) Savannas of Africa

The Savanna biome of Africa is famous for supporting some of the world’s largest populations of wild animals. It is characterized by extensive grasslands with scattered trees, a warm climate throughout the year, and distinct wet and dry seasons. These environmental conditions provide abundant grazing opportunities for large herbivorous animals such as zebras, wildebeests, antelopes, gazelles, giraffes, buffaloes, and elephants.

The large population of herbivores creates an ideal ecological base for numerous carnivorous animals. Predators such as lions, leopards, cheetahs, jackals, and hyenas thrive in the African savannas because of the availability of prey. The food chain in this ecosystem is highly developed, making it one of the most biologically productive grassland regions in the world. The famous wildlife reserves and national parks of East and Southern Africa, including the Serengeti National Park and Masai Mara National Reserve, are located within the savanna region and are known for their rich wildlife populations and seasonal animal migrations.

In contrast, Equatorial rainforests possess dense vegetation that restricts the movement of large grazing herds, while the Taiga biome of high latitudes is dominated by coniferous forests and supports relatively fewer large herbivores and predators. The Campos of Brazil are tropical grasslands, but they do not support the immense concentration and diversity of large mammals that characterize the African savannas.

The African savanna is often referred to as the world’s greatest natural wildlife habitat because of its extensive grass cover, rich biodiversity, complex predator-prey relationships, and large-scale seasonal migrations of herbivorous animals.

3. Match List-I with List-II and select the correct answer from the codes given below. (JUNE 2014)

List-I (Organisms) | List-II (Trophic levels)
A. Green plants — I. Decomposer
B. Animal — II. Primary consumer
C. Plant parasites — III. Secondary consumer
D. Fungi — IV. Producer

Codes

A | B | C | D

(1) IV | III | II | I
(2) II | I | IV | III
(3) III | II | I | IV
(4) I | II | IV | III

Correct Answer: (1) IV – III – II – I

Ecological systems are organized into different trophic levels, which represent the position occupied by organisms in a food chain based on how they obtain energy. Energy enters the ecosystem through producers and then passes through various levels of consumers before finally reaching decomposers.

Green plants are classified as producers because they manufacture their own food through the process of photosynthesis using sunlight, carbon dioxide, and water. They form the first trophic level and serve as the primary source of energy for all other organisms in an ecosystem. Therefore, A matches with IV.

Animals are generally consumers because they cannot prepare their own food. In this matching question, animals are associated with the secondary consumer level. Secondary consumers feed on primary consumers and occupy a higher position in the food chain. Therefore, B matches with III.

Plant parasites derive nourishment directly from living plants. Since they obtain food from producers, they function as primary consumers in the trophic structure. Examples include parasitic plants such as dodder and various herbivorous organisms that feed directly on plant tissues. Therefore, C matches with II.

Fungi play a crucial role as decomposers. They break down dead organic matter and convert complex substances into simpler nutrients, which are returned to the soil and reused by plants. This process is essential for nutrient cycling and maintaining ecosystem productivity. Therefore, D matches with I.

The correct matching is A–IV, B–III, C–II, D–I, which corresponds to Option (1). Producers, consumers, and decomposers together form the functional components of an ecosystem, ensuring the continuous flow of energy and recycling of nutrients through ecological food chains and food webs.

4. Which one of the following marine ecosystems has the highest primary production? (DEC 2014)

(1) Open seas
(2) Tidal estuaries
(3) Continental shelves
(4) Algae beds and reefs

Correct Answer: (4) Algae beds and reefs

Primary production refers to the rate at which producers, mainly plants and algae, convert solar energy into organic matter through photosynthesis. It is a key indicator of ecosystem productivity and forms the foundation of food chains and food webs. In marine environments, primary productivity varies significantly depending on the availability of sunlight, nutrients, and suitable environmental conditions.

Algae beds and coral reefs are among the most productive ecosystems on Earth. These ecosystems receive abundant sunlight because they are generally found in shallow waters. Algae, including seaweeds and microscopic phytoplankton, perform photosynthesis at very high rates. Coral reefs also support a symbiotic relationship between corals and photosynthetic algae known as zooxanthellae, which greatly enhances biological productivity. The efficient recycling of nutrients within reef ecosystems allows them to sustain a large biomass despite often occurring in nutrient-poor tropical waters.

Open seas cover the largest area of the oceans, but their productivity per unit area is relatively low because nutrients are often scarce in surface waters far from the coast. Continental shelves are more productive than the open ocean because of better nutrient availability and sunlight penetration. Tidal estuaries are also highly productive ecosystems due to the mixing of freshwater and seawater, which brings abundant nutrients and supports rich biological communities.

When productivity is measured on a unit-area basis, algae beds and reefs exhibit the highest levels of primary production among marine ecosystems. Their high photosynthetic activity, efficient nutrient cycling, rich biodiversity, and dense concentration of producers make them exceptionally productive environments that support a vast variety of marine organisms, including fish, mollusks, crustaceans, and numerous other aquatic species.

5. Hekistotherm plants are found in (DEC 2014)

(1) Mediterranean climate
(2) Hot desert
(3) Equatorial climate
(4) Cold desert

Correct Answer: (4) Cold desert

Hekistotherm plants are plants that are adapted to extremely low-temperature environments. The term is derived from Greek words meaning “least heat,” indicating vegetation that can survive and grow under very cold climatic conditions. These plants are specially adapted to regions where temperatures remain low for most of the year and where the growing season is extremely short.

Cold deserts are characterized by low precipitation, harsh winters, strong winds, and freezing temperatures. Vegetation in these regions is sparse and consists mainly of hardy species that can tolerate frost, low soil temperatures, and limited moisture availability. Hekistotherm plants possess several adaptations such as dwarf growth forms, reduced leaf surfaces, deep or extensive root systems, and the ability to remain dormant during unfavorable periods. These characteristics help them conserve energy and withstand severe climatic stress.

Examples of cold desert environments include regions such as Ladakh in Ladakh, parts of Mongolia, the high plateaus of Tibet, and the polar desert regions of the Arctic and Antarctic. Vegetation commonly found in such areas includes mosses, lichens, cushion plants, and certain cold-resistant grasses and shrubs.

The other climatic regions listed in the question support different categories of vegetation. Mediterranean climates are associated with sclerophyllous vegetation adapted to dry summers, hot deserts support xerophytic plants adapted to water scarcity, and equatorial climates are dominated by luxuriant evergreen forests that thrive under high temperatures and abundant rainfall. Hekistotherm vegetation is specifically associated with environments where extremely low temperatures act as the primary ecological control on plant growth and distribution.

6. How many essential nutrients are required by plants to fulfil their growth requirements? (JUNE 2015)

(1) 24
(2) 22
(3) 20
(4) 18

Correct Answer: (4) 18

Plants require a specific set of essential nutrients to complete their life cycle, grow normally, reproduce, and perform various physiological functions. An element is considered essential when its absence prevents the plant from completing its life cycle and when no other element can completely substitute its role. According to the widely accepted classification used in plant nutrition and ecology, plants require 18 essential nutrients for proper growth and development.

These nutrients are divided into different categories based on the quantity required by plants. Carbon (C), Hydrogen (H), and Oxygen (O) are obtained mainly from air and water and form the basic structural components of plant tissues. The macronutrients required in relatively large amounts include Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), and Sulphur (S). These elements play crucial roles in photosynthesis, protein synthesis, energy transfer, enzyme activation, and cell development.

In addition, plants require several micronutrients in smaller quantities, including Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B), Molybdenum (Mo), Chlorine (Cl), and Nickel (Ni). Although needed in trace amounts, these nutrients are indispensable for metabolic activities, enzyme functions, and reproductive growth. Even a minor deficiency of any essential nutrient can lead to stunted growth, chlorosis, reduced yield, or other physiological disorders.

The concept of essential plant nutrients has evolved through advances in plant physiology and soil science. Earlier classifications recognized fewer elements, but subsequent research established the essential role of additional nutrients such as Nickel, bringing the accepted number to 18 essential nutrients required for normal plant growth and development.

7. Mesophytes are predominant in (JUNE 2015)

(1) Tropical region
(2) Sub-polar region
(3) Temperate region
(4) Polar region

Correct Answer: (3) Temperate region

Mesophytes are plants that grow under conditions of moderate moisture supply. They are neither adapted to extremely dry environments like xerophytes nor to excessively wet environments like hydrophytes. These plants require a balanced amount of water in the soil and atmosphere for their normal growth and development. Most agricultural crops, grasses, shrubs, and deciduous trees belong to this category.

The temperate region provides the most favorable conditions for mesophytic vegetation. Moderate temperatures, adequate rainfall, distinct seasons, and reasonably fertile soils create an environment where plants receive sufficient moisture without facing prolonged drought or excessive waterlogging. As a result, mesophytes dominate the natural vegetation of many temperate areas. Deciduous forests, mixed forests, and temperate grasslands are largely composed of mesophytic species.

Mesophytes possess structural characteristics that reflect their adaptation to moderate environmental conditions. Their roots are generally well developed but not exceptionally deep, their leaves are of normal size with a moderate number of stomata, and they lack the special water-conserving features seen in desert plants. These characteristics enable efficient photosynthesis, respiration, and transpiration under average climatic conditions.

The tropical region contains diverse vegetation types, including evergreen forests where moisture conditions are often very high. Sub-polar and polar regions experience extremely low temperatures, short growing seasons, and limited plant diversity, conditions that favor specially adapted cold-resistant vegetation rather than mesophytes. The greatest concentration and dominance of mesophytic vegetation are associated with the moderate climatic conditions of the temperate region, where moisture availability and temperature remain suitable for sustained plant growth throughout much of the year.

8. The place where an organism or community of organisms lives is called (JUNE 2015)

(1) Environment
(2) Atmosphere
(3) Habitat
(4) Society

Correct Answer: (3) Habitat

A habitat is the natural place or environment in which an organism, population, or community of organisms lives, grows, and reproduces. It provides all the essential conditions necessary for survival, including food, water, shelter, space, and suitable climatic conditions. Every species occupies a particular habitat that supports its biological and ecological requirements.

The concept of habitat is fundamental in ecology because it helps explain the distribution and adaptation of organisms. Habitats can vary greatly in size and characteristics. A forest, grassland, desert, river, pond, mountain, wetland, or ocean can all serve as habitats for different species. For example, fish live in aquatic habitats, camels are adapted to desert habitats, and polar bears are associated with Arctic habitats. The physical and biological features of a habitat influence the kinds of organisms that can survive there.

A habitat consists of both biotic factors and abiotic factors. Biotic factors include plants, animals, microorganisms, and their interactions, while abiotic factors include temperature, rainfall, sunlight, soil, water, and air. The combination of these factors creates specific environmental conditions that determine the suitability of a habitat for particular organisms. Organisms often develop structural, physiological, and behavioral adaptations that enable them to survive successfully within their habitats.

The term environment refers to the total surroundings and conditions affecting an organism, which is a broader concept than habitat. Atmosphere specifically denotes the gaseous envelope surrounding the Earth, while society refers to a group of individuals living together and interacting. In ecological terminology, the specific place where an organism or a community of organisms lives is known as its habitat, which serves as the basic ecological unit for understanding species distribution, adaptation, and ecosystem functioning.

9. Photosynthesis is the process by which (JUNE 2015)

(1) Radiant energy is converted into chemical energy
(2) Radiant energy is converted into thermal energy
(3) Radiant energy is converted into bio-energy
(4) Radiant energy is converted into geothermal energy

Correct Answer: (1) Radiant energy is converted into chemical energy

Photosynthesis is a fundamental biological process through which green plants, algae, and certain bacteria capture radiant energy from sunlight and transform it into chemical energy stored in organic compounds. This process takes place primarily in the chloroplasts of plant cells, where the pigment chlorophyll absorbs solar energy and initiates a series of biochemical reactions.

During photosynthesis, plants utilize carbon dioxide from the atmosphere and water absorbed from the soil to produce glucose and other carbohydrates. The energy from sunlight becomes stored in the chemical bonds of these organic molecules. Oxygen is released as a by-product, making photosynthesis essential not only for plant life but also for the maintenance of atmospheric oxygen required by most living organisms.

The process can be represented by the equation:

6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂

Photosynthesis serves as the primary source of energy for nearly all ecosystems. The energy captured by plants is transferred through food chains and food webs to herbivores, carnivores, and decomposers. For this reason, green plants are known as primary producers and form the foundation of ecological energy flow. The process also plays a vital role in the carbon cycle by removing carbon dioxide from the atmosphere and incorporating it into living biomass.

The other options do not accurately describe the outcome of photosynthesis. Although some solar energy may eventually be transformed into heat during metabolic activities, the direct result of photosynthesis is the conversion of radiant energy into chemical energy stored in carbohydrates. This stored energy supports plant growth, reproduction, respiration, and the energy requirements of virtually all organisms that depend directly or indirectly on photosynthetic producers.

10. Which one of the following is not a macronutrient to plants? (JUNE 2015)

(1) Carbon
(2) Iron
(3) Nitrogen
(4) Oxygen

Correct Answer: (2) Iron

Plants require a variety of essential nutrients for their growth, development, and metabolic activities. These nutrients are broadly classified into macronutrients and micronutrients based on the quantity required by plants. Macronutrients are needed in relatively large amounts because they form major structural and functional components of plant tissues, whereas micronutrients are required only in trace quantities but remain indispensable for normal growth.

Carbon, oxygen, and nitrogen are all classified as macronutrients. Carbon and oxygen constitute a major portion of plant biomass and are obtained mainly from atmospheric carbon dioxide and water. Nitrogen is one of the most important macronutrients, playing a crucial role in the formation of proteins, nucleic acids, chlorophyll, enzymes, and other vital cellular constituents. Deficiency of nitrogen often results in stunted growth and yellowing of leaves.

Iron, on the other hand, is a micronutrient. Although plants require only small amounts of iron, it performs essential functions in chlorophyll synthesis, electron transport, respiration, and enzyme activation. Iron deficiency can cause chlorosis, particularly in young leaves, where the leaf tissue becomes yellow while the veins remain green. Its requirement in very small quantities places it in the micronutrient category rather than among macronutrients.

The essential macronutrients of plants include carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur. Important micronutrients include iron, manganese, zinc, copper, boron, molybdenum, chlorine, and nickel. The distinction between macro- and micronutrients is based on the quantity required by plants and not on the importance of the element, as both groups are essential for completing the plant life cycle and maintaining normal physiological functions.

11. Identify the correct sequence of vegetation belts in ascending order in a mountain environment. (DEC 2015)

(1) Sub-montane → Montane → Sub-alpine → Alpine
(2) Alpine → Sub-alpine → Montane → Sub-montane
(3) Montane → Sub-montane → Alpine → Sub-alpine
(4) Alpine → Montane → Sub-alpine → Sub-montane

Correct Answer: (1) Sub-montane → Montane → Sub-alpine → Alpine

In mountain environments, vegetation changes systematically with increasing altitude due to variations in temperature, precipitation, humidity, soil conditions, and the length of the growing season. This vertical arrangement of plant communities is known as altitudinal zonation or vertical zonation of vegetation. As elevation increases, temperature decreases and environmental conditions become progressively harsher, leading to distinct vegetation belts.

The lowest vegetation belt in mountainous regions is the sub-montane belt, which occurs at the foothills and lower slopes. This zone generally supports tropical or subtropical vegetation depending on latitude and local climatic conditions. Trees are relatively tall and diverse because temperatures remain comparatively warm and the growing season is longer.

Above the sub-montane zone lies the montane belt, characterized by temperate forests. In many mountain systems, this belt contains broad-leaved deciduous forests and coniferous forests. Cooler temperatures and higher elevations create conditions suitable for species adapted to moderate climatic stress.

The next higher zone is the sub-alpine belt, which represents a transitional region between dense forests and treeless alpine landscapes. Vegetation becomes shorter and less dense, with stunted trees, shrubs, and hardy grasses adapted to colder temperatures, stronger winds, and shorter growing seasons.

At the highest elevations occurs the alpine belt, situated above the tree line. This zone is characterized by alpine meadows, grasses, sedges, mosses, lichens, and other cold-resistant plants. Trees are generally absent because environmental conditions are too severe to support their growth. Low temperatures, intense solar radiation, strong winds, and prolonged snow cover dominate this region.

The ascending sequence of vegetation belts from lower to higher elevations is Sub-montane → Montane → Sub-alpine → Alpine. This pattern is clearly visible in major mountain systems such as the Himalayas, where vegetation changes progressively with altitude, reflecting the close relationship between climate and plant distribution.

13. Which one of the following percentages does India contribute to the world’s biodiversity? (JULY 2016)

(1) 2%
(2) 4%
(3) 6%
(4) 8%

Correct Answer: (4) 8%

India is recognized as one of the world’s most biologically rich countries and is classified as a megadiverse country. Although India occupies only about 2.4% of the world’s geographical area, it supports approximately 8% of the world’s recorded biodiversity. This remarkable concentration of biological wealth reflects the country’s wide range of climatic conditions, landforms, ecosystems, and ecological habitats.

The diversity of India’s physical environment contributes significantly to its biodiversity. The country contains ecosystems ranging from the high-altitude regions of the Himalayas to the tropical rainforests of the Western Ghats, the deserts of Thar Desert, extensive river systems, wetlands, grasslands, mangrove forests, and long coastal regions. These varied habitats support an enormous number of plant and animal species, many of which are endemic and found nowhere else in the world.

India is home to several global biodiversity hotspots, including the Western Ghats, the Eastern Himalayas, the Indo-Burma region, and parts of Sundaland represented by the Andaman and Nicobar Islands. These regions possess exceptionally high species richness and endemism. Thousands of species of flowering plants, mammals, birds, reptiles, amphibians, fishes, and insects have been recorded within the country, making it one of the most important centres of biological diversity on Earth.

The country’s biodiversity has immense ecological, economic, scientific, and cultural value. It supports agriculture, forestry, fisheries, medicine, ecosystem stability, and the livelihoods of millions of people. India’s contribution of about 8% of global biodiversity is particularly significant when compared to its relatively small share of the world’s land area, highlighting its exceptional ecological richness and environmental importance.

14. The endemic species of India are mainly found in (JULY 2016)

(1) Eastern India
(2) Central India
(3) North-East India
(4) North-West India

Correct Answer: (3) North-East India

Endemic species are those species of plants or animals that are naturally restricted to a particular geographical area and are not found anywhere else in the world. Endemism develops due to factors such as geographical isolation, unique climatic conditions, evolutionary history, and specialized habitats. Regions with high levels of endemism are of great importance for biodiversity conservation because the loss of these habitats may result in the global extinction of many species.

In India, a significant concentration of endemic species is found in North-East India, which forms part of the globally recognized Indo-Burma Biodiversity Hotspot. The region is characterized by dense forests, high rainfall, varied altitudinal zones, complex topography, and a wide range of ecological niches. These environmental conditions have promoted the evolution and survival of numerous unique species over long geological periods.

North-East India includes states such as Arunachal Pradesh, Assam, Meghalaya, Manipur, Mizoram, Nagaland, Tripura, and Sikkim. The region supports a remarkable diversity of orchids, bamboos, medicinal plants, mammals, birds, reptiles, amphibians, and insects. Many of these species occur only within this area and are not naturally distributed elsewhere.

The isolation created by mountain ranges, deep valleys, and dense forests has contributed to speciation and endemism. The region also serves as a meeting point of the Indian, Indo-Malayan, and Indo-Chinese biogeographical realms, resulting in exceptional biological richness. While other parts of India, particularly the Western Ghats, also possess a high degree of endemism, North-East India is recognized for its extraordinary concentration of endemic flora and fauna, making it one of the most biologically significant regions of the country.

15. Who defined geography as human ecology? (JAN 2017)

(1) Hartshorne
(2) Schaefer
(3) Ellen Semple
(4) Barrows

Correct Answer: (4) Barrows

Harlan H. Barrows is credited with defining geography as “human ecology.” In his presidential address to the Association of American Geographers in 1922, Barrows argued that geography should focus on the study of the relationships between human beings and their environment. He believed that the central concern of geography was understanding how humans adapt to, utilize, and modify their surroundings.

The concept of human ecology was borrowed from biological ecology, where the interactions between organisms and their environment are studied. Barrows extended this idea to human societies and emphasized that geographers should investigate the ways in which people respond to environmental opportunities and constraints. His approach shifted attention from the mere description of physical features to the dynamic interaction between humans and nature.

Barrows’ view represented an important stage in the evolution of geographical thought. He sought to establish geography as a discipline that examines the functional relationships between environmental conditions and human activities. This perspective encouraged studies of settlement patterns, land use, resource utilization, agriculture, transportation, and other aspects of human adaptation to geographical environments.

The other scholars listed in the question are associated with different contributions to geography. Richard Hartshorne emphasized the concept of areal differentiation and the study of regional uniqueness. Fred K. Schaefer criticized exceptionalism in geography and advocated the search for scientific laws. Ellen Churchill Semple was a prominent supporter of environmental determinism and was influenced by the ideas of Friedrich Ratzel. The specific definition of geography as human ecology is most closely associated with Harlan H. Barrows, whose ideas contributed significantly to the development of human-environment studies within geographical research.