Chapter 3
Ecology and Vegetation
MBBS and BDS entrance past exam questions
Past questions and answers
65 questions set from this chapter. Most repeated first.
- 2016 · NEET-UG (India) · 4 marks
Which of the following is the most important cause of animals and plants being driven to extinction?
(a) Over-exploitation
(b) Alien species invasion
(c) Habitat loss and fragmentation
(d) Co-extinctions
Similar questions: Cause of extinction (2019 · NEET-UG (India))
Answer
(c) Habitat loss and fragmentation
Habitat loss and fragmentation is the most important cause of extinction, as in the Amazon rainforest being cleared. Over-exploitation, alien invasion and co-extinction are real but less important causes.
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- 2019 · NEET-UG (India) · 4 marks
Which of the following is the most important cause for animals and plants being driven to extinction?
(a) Economic exploitation
(b) Alien species invasion
(c) Habitat loss and fragmentation
(d) Drought and floods
Similar questions: Cause of extinction (2016 · NEET-UG (India))
Answer
(c) Habitat loss and fragmentation
Habitat loss and fragmentation is the most important cause of extinction. It is the first of the "evil quartet", and tropical rain forest clearance is a typical example. Alien species invasion, over-exploitation and co-extinction matter, but they affect fewer species. Drought and floods are natural events and are not considered a main cause.
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- 2016 · NEET-UG (India) · 4 marks
Gause's principle of competitive exclusion states that:
(a) More abundant species will exclude the less abundant species through competition.
(b) Competition for the same resources excludes species having different food preferences.
(c) No two species can occupy the same niche indefinitely for the same limiting resources.
(d) Larger organisms exclude smaller ones through competition.
Answer
(c) No two species can occupy the same niche indefinitely for the same limiting resources.
Gause's competitive exclusion principle: two closely related species competing for the same limiting resource cannot coexist stably; the better competitor eliminates the other, or they shift niches. Abundance or body size (a, d) does not decide the outcome, and (b) wrongly says species with different food preferences are excluded, when different preferences actually allow coexistence.
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- 2016 · NEET-UG (India) · 4 marks
Which one of the following is a characteristic feature of cropland ecosystem?
(a) Absence of soil organisms
(b) Least genetic diversity
(c) Absence of weeds
(d) Ecological succession
Answer
(b) Least genetic diversity
Cropland ecosystems are managed monocultures of a few genetically uniform crops, so genetic diversity is least. They have soil organisms and weeds (which are removed but present), and succession is arrested by human management.
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- 2016 · NEET-UG (India) · 4 marks
Joint Forest Management Concept was introduced in India during:
(a) 1960s
(b) 1970s
(c) 1980s
(d) 1990s
Answer
(c) 1980s
Joint Forest Management (JFM) in India began in the 1980s, with early experiments in West Bengal (Arabari) and Odisha, formalised by the 1988 National Forest Policy and the 1990 government resolution. Local communities protect forest and share in its produce. The 1960s and 1970s predate the concept, and the 1990s saw its wide spread, not its introduction.
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- 2016 · NEET-UG (India) · 4 marks
The term ecosystem was coined by:
(a) E.P. Odum
(b) A.G. Tansley
(c) E. Haeckel
(d) E. Warming
Answer
(b) A.G. Tansley
The term "ecosystem" was coined by the British ecologist A.G. Tansley in 1935. E.P. Odum is known for his textbook and work on ecosystem ecology, Haeckel coined "ecology" (oekologie), and Warming is known for plant ecology.
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- 2016 · NEET-UG (India) · 4 marks
When does the growth rate of a population following the logistic model equal zero? The logistic model is given as :
(a) when N/K is exactly one.
(b) when N nears the carrying capacity of the habitat.
(c) when N/K equals zero.
(d) when death rate is greater than birth rate.
Answer
(a) when N/K is exactly one.
In the growth rate is zero when , i.e. and , the carrying capacity. Option (b) is tempting, but "nears" the carrying capacity means growth is only slowing and not yet zero. means , where there is no population to grow, and a death rate above the birth rate gives negative growth, not zero.
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- 2016 · NEET-UG (India) · 4 marks
Which of the following would appear as the pioneer organisms on bare rocks?
(a) Lichens
(b) Liverworts
(c) Mosses
(d) Green algae
Answer
(a) Lichens
Lichens are the pioneer species on bare rock in primary xerarch succession. They secrete acids that weather the rock and form a little soil. Liverworts and mosses follow later, using the soil the lichens help build, and green algae are not the typical rock colonisers.
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- 2016 · NEET-UG (India) · 4 marks
Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers?
(a) Nitrous oxide
(b) Ozone
(c) Ammonia
(d) Methane
Answer
(b) Ozone
The stratospheric ozone layer absorbs harmful UV-B radiation. When ozone is depleted, more UV-B reaches the earth, damaging DNA and causing skin cancers and cataracts. Nitrous oxide, ammonia and methane are not the gases that shield against UV.
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- 2016 · NEET-UG (India) · 4 marks
A river with an inflow of domestic sewage rich in organic waste may result in:
(a) Drying of the river very soon due to algal bloom.
(b) Increased population of aquatic food web organisms.
(c) An increased production of fish due to biodegradable nutrients.
(d) Death of fish due to lack of oxygen.
Answer
(d) Death of fish due to lack of oxygen.
Sewage rich in organic waste is decomposed by microbes, which raises the biochemical oxygen demand (BOD). Oxygen in the water falls sharply, and fish and other aquatic life die. Algal blooms come from inorganic nutrients such as nitrate and phosphate (eutrophication), but even then the water does not "dry up", and more fish production is not the result of heavy sewage.
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- 2015 · NEET-UG (India) · 4 marks
Most animals that live in deep oceanic water are:
(a) detritivores
(b) primary consumers
(c) secondary consumers
(d) tertiary consumers
Answer
(a) detritivores
The deep ocean receives no light, so there are no producers; the animals there depend on dead organic matter (detritus) that sinks down from above, making most of them detritivores. Consumers of living prey would need living producers lower in the chain.
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- 2015 · NEET-UG (India) · 4 marks
An association of individuals of different species living in the same habitat and having functional interactions is:
(a) Population
(b) Ecological niche
(c) Biotic community
(d) Ecosystem
Answer
(c) Biotic community
A biotic community is an assemblage of populations of different species living in the same area and interacting with each other. A population is a single species, a niche is a species' functional role, and an ecosystem also includes the abiotic components.
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- 2015 · NEET-UG (India) · 4 marks
In which of the following both pairs have correct combination?
Gaseous nutrient cycle Sedimentary nutrient cycle (a) Sulphur and Phosphorus Carbon and Nitrogen (b) Carbon and Nitrogen Sulphur and Phosphorus (c) Carbon and Sulphur Nitrogen and Phosphorus (d) Nitrogen and Sulphur Carbon and Phosphorus
(a) Row (a)
(b) Row (b)
(c) Row (c)
(d) Row (d)
Answer
(b) Row (b)
Carbon and nitrogen have a gaseous reservoir (atmosphere) so they are gaseous cycles, while sulphur and phosphorus have a reservoir in the earth's crust and are sedimentary cycles. Other rows swap or mix these cycle types.
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- 2015 · NEET-UG (India) · 4 marks
In which of the following interactions both partners are adversely affected?
(a) Mutualism
(b) Competition
(c) Predation
(d) Parasitism
Answer
(b) Competition
In competition both species are harmed (-/-) because they struggle for the same limiting resource. Mutualism benefits both (+/+), while in predation and parasitism one gains and the other is harmed.
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- 2015 · NEET-UG (India) · 4 marks
The species confined to a particular region and not found elsewhere is termed as:
(a) Rare
(b) Keystone
(c) Alien
(d) Endemic
Answer
(d) Endemic
Endemic species are confined to one region and found nowhere else. A keystone species has a disproportionate effect on its community, an alien species is introduced from elsewhere, and a rare species is merely few in number.
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- 2015 · NEET-UG (India) · 4 marks
Eutrophication of water bodies leading to killing of fishes is mainly due to non-availability of:
(a) oxygen
(b) food
(c) light
(d) essential minerals
Answer
(a) oxygen
Eutrophication adds nutrients that cause algal blooms; when the algae die, decomposers use up dissolved oxygen (high BOD). Fish die from oxygen shortage, not from lack of food, light or minerals.
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- 2015 · NEET-UG (India) · 4 marks
Acid rain is caused by increase in the atmospheric concentration of:
(a) and dust
(b) and
(c) and CO
(d) and CO
Answer
(b) and
Sulphur dioxide and nitrogen oxides react with water in the atmosphere to form sulphuric and nitric acids, giving acid rain (pH below 5.6). O3, CO and CO2 do not form strong acids in this way, so the other options are wrong.
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- 2015 · NEET-UG (India) · 4 marks
Increase in concentration of the toxicant at successive trophic levels is known as:
(a) Biogeochemical cycling
(b) Biomagnification
(c) Biodeterioration
(d) Biotransformation
Answer
(b) Biomagnification
Biomagnification is the increase in concentration of a toxicant (e.g. DDT, mercury) at successive trophic levels because it is not metabolised or excreted. Biogeochemical cycling is nutrient movement, and biotransformation is chemical change of a substance.
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- 2015 · NEET-UG (India) · 4 marks
During ecological succession:
(a) the changes lead to a community that is in near equilibrium with the environment and is called pioneer community
(b) the gradual and predictable change in species composition occurs in a given area
(c) the establishment of a new biotic community is very fast in its primary phase
(d) the numbers and types of animals remain constant
Answer
(b) the gradual and predictable change in species composition occurs in a given area
Ecological succession is the gradual, orderly and predictable change in species composition of a community over time. The near-equilibrium community is the climax, not the pioneer; primary succession is very slow, and animal numbers and types change along with the plants.
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- 2015 · NEET-UG (India) · 4 marks
Which of the following are most suitable indicators of pollution in the environment?
(a) Fungi
(b) Lichens
(c) Conifers
(d) Algae
Answer
(b) Lichens
Lichens are very sensitive to SO2, and do not grow in polluted areas, so they are used as indicators of SO2 pollution. Fungi, conifers and algae alone are not used as standard indicators.
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- 2014 · NEET-UG (India) · 4 marks
Just as a person moving from Delhi to Shimla to escape the heat for the duration of hot summer, thousands of migratory birds from Siberia and other extremely cold northern regions move to:
(a) Meghalaya
(b) Corbett National Park
(c) Keoladeo National Park
(d) Western Ghat
Answer
(c) Keoladeo National Park
Keoladeo Ghana National Park (Bharatpur, Rajasthan) is a famous wetland sanctuary where Siberian cranes and other migratory birds winter. Corbett and the Western Ghats are not known for this migration.
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- 2014 · NEET-UG (India) · 4 marks
A species facing extremely high risk of extinction in the immediate future is called:
(a) Endemic
(b) Critically Endangered
(c) Extinct
(d) Vulnerable
Answer
(b) Critically Endangered
In the IUCN Red List, Critically Endangered is the category for species facing an extremely high risk of extinction in the immediate future. Vulnerable and Endangered are lower-risk categories; Endemic only describes restricted distribution.
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- 2014 · NEET-UG (India) · 4 marks
Match the following and select the correct option:
Column I Column II (a) Earthworm (i) Pioneer species (b) Succession (ii) Detritivore (c) Ecosystem service (iii) Natality (d) Population growth (iv) Pollination
Code (a), (b), (c), (d):
(a) (iv), (i), (iii), (ii)
(b) (iii), (ii), (iv), (i)
(c) (ii), (i), (iv), (iii)
(d) (i), (ii), (iii), (iv)
Answer
(c) (ii), (i), (iv), (iii)
Earthworm is a detritivore (ii), succession starts with a pioneer species (i), pollination is an ecosystem service (iv), and natality (birth rate) is a factor in population growth (iii). The other codes mismatch at least one pair, e.g. pairing earthworm with pollination.
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- 2014 · NEET-UG (India) · 4 marks
A location with luxuriant growth of lichens on the trees indicates that the:
(a) trees are heavily infested
(b) location is highly polluted
(c) location is not polluted
(d) trees are very healthy
Answer
(c) location is not polluted
Lichens are very sensitive to sulphur dioxide and other air pollutants, so they are bioindicators of air quality. Luxuriant lichen growth therefore means clean air; in a polluted area lichens fail to grow.
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- 2014 · NEET-UG (India) · 4 marks
An example of ex situ conservation is:
(a) Seed Bank
(b) Wildlife Sanctuary
(c) Sacred Grove
(d) National Park
Answer
(a) Seed Bank
Ex situ conservation protects species outside their natural habitat, in places such as seed banks, gene banks, botanical gardens and zoos. Wildlife sanctuaries, sacred groves and national parks are all in situ methods, conserving species in their natural habitat.
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- 2014 · NEET-UG (India) · 4 marks
The organization which publishes the Red List of species is:
(a) IUCN
(b) UNEP
(c) WWF
(d) ICFRE
Answer
(a) IUCN
The International Union for Conservation of Nature and Natural Resources maintains and publishes the Red List of threatened species. UNEP is the UN environment programme, WWF is a conservation NGO and ICFRE is India's forestry research council; none of them publishes the Red List.
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- 2014 · NEET-UG (India) · 4 marks
The zone of atmosphere in which the ozone layer is present is called:
(a) Mesosphere
(b) Stratosphere
(c) Troposphere
(d) Ionosphere
Answer
(b) Stratosphere
The ozone layer lies in the stratosphere, roughly 15-35 km above the earth, where it absorbs harmful UV radiation. The troposphere is the lowest layer containing weather, the mesosphere is above the stratosphere, and the ionosphere is the region of ionised gases high in the atmosphere.
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- 2014 · NEET-UG (India) · 4 marks
A scrubber in the exhaust of a chemical industrial plant removes:
(a) particulate matter of the size 5 micrometer or above
(b) gases like ozone and methane
(c) particulate matter of the size 2.5 micrometer or less
(d) gases like sulphur dioxide
Answer
(d) gases like sulphur dioxide
A scrubber passes the exhaust gases through a spray of water or lime, which dissolves or absorbs gases such as sulphur dioxide. Particulate matter is removed by electrostatic precipitators, and scrubbers do not remove ozone or methane.
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- 2014 · NEET-UG (India) · 4 marks
If 20 J of energy is trapped at producer level, then how much energy will be available to peacock as food in the following chain?
plant → mice → snake → peacock
(a) 0.002 J
(b) 0.2 J
(c) 0.0002 J
(d) 0.02 J
Answer
(d) 0.02 J
By the 10 percent law, only about 10 percent of energy passes to the next trophic level. Plant 20 J mice J snake J peacock J.
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- 2013 · NEET-UG (India) · 4 marks
Natural reservoir of phosphorus is:
(a) Sea water
(b) Animal bones
(c) Rock
(d) Fossils
Answer
(c) Rock
Phosphorus has a sedimentary cycle, and its natural reservoir is phosphate rock (it is released slowly by weathering). The atmosphere is not a reservoir of phosphorus.
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- 2013 · NEET-UG (India) · 4 marks
Secondary productivity is rate of formation of new organic matter by:
(a) Producer
(b) Parasite
(c) Consumer
(d) Decomposer
Answer
(c) Consumer
Secondary productivity is the rate of formation of new organic matter by consumers. Primary productivity is by producers.
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- 2013 · NEET-UG (India) · 4 marks
Which one of the following is not used for ex situ plant conservation?
(a) Field gene banks
(b) Seed banks
(c) Shifting cultivation
(d) Botanical Gardens
Answer
(c) Shifting cultivation
Shifting (jhum) cultivation is a farming practice that destroys forest and is not conservation. Field gene banks, seed banks and botanical gardens are ex situ methods.
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- 2013 · NEET-UG (India) · 4 marks
Kyoto Protocol was endorsed at:
(a) CoP-3
(b) CoP-5
(c) CoP-6
(d) CoP-4
Answer
(a) CoP-3
The Kyoto Protocol was adopted at the third Conference of the Parties (CoP-3) of the UNFCCC in Kyoto, Japan, in 1997. It set binding targets to cut greenhouse gas emissions.
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- 2017 · NEET-UG (India) · 4 marks
The region of Biosphere Reserve which is legally protected and where no human activity is allowed is known as
(a) Core zone
(b) Buffer zone
(c) Transition zone
(d) Restoration zone
Answer
(a) Core zone
A biosphere reserve has a core zone, a buffer zone and a transition zone. The core zone is legally protected and no human activity is allowed. Limited activities such as research and tourism are allowed in the buffer zone, and the transition zone has settlements and economic use.
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- 2017 · NEET-UG (India) · 4 marks
Mycorrhizae are the example of
(a) Fungistasis
(b) Amensalism
(c) Antibiosis
(d) Mutualism
Answer
(d) Mutualism
In mycorrhizae the fungus absorbs phosphorus and water for the plant, and the plant supplies carbohydrates to the fungus. Both partners benefit, so this is mutualism. Amensalism and antibiosis involve harm to one species.
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- 2017 · NEET-UG (India) · 4 marks
Plants which produce characterstic pneumatophores and show vivipary belong to
(a) Mesophytes
(b) Halophytes
(c) Psammophytes
(d) Hydrophytes
Answer
(b) Halophytes
Mangrove plants live in saline, waterlogged soil. They have pneumatophores (breathing roots) and show vivipary, so they are halophytes. Mesophytes, psammophytes (sand dwellers) and hydrophytes do not show both features.
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- 2017 · NEET-UG (India) · 4 marks
Which one of the following is related to Ex-situ conservation of threatened animals and plants?
(a) Wildlife Safari parks
(b) Biodiversity hot spots
(c) Amazon rainforest
(d) Himalayan region
Answer
(a) Wildlife Safari parks
Ex-situ conservation takes the organism out of its natural habitat, as in zoos, safari parks and botanical gardens. Biodiversity hot spots, the Amazon rainforest and the Himalayan region are natural areas, so they belong to in-situ conservation.
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- 2017 · NEET-UG (India) · 4 marks
Which ecosystem has the maximum biomass?
(a) Forest ecosystem
(b) Grassland ecosystem
(c) Pond ecosystem
(d) Lake ecosystem
Answer
(a) Forest ecosystem
Forests contain large trees with a large amount of woody tissue, so they have the highest standing crop of biomass. Grassland, pond and lake ecosystems hold much less.
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- 2017 · NEET-UG (India) · 4 marks
Presence of plants arranged into well defined vertical layers depending on their height can be seen best in :
(a) Tropical Savannah
(b) Tropical Rain Forest
(c) Grassland
(d) Temperate Forest
Answer
(b) Tropical Rain Forest
Tropical rain forests have the greatest structural complexity. Their plants form distinct vertical layers (emergent, canopy, understory, shrub and herb layers). Savanna and grassland have few strata, and temperate forests have fewer layers than rain forests.
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- 2017 · NEET-UG (India) · 4 marks
Asymptote in a logistic growth curve is obtained when
(a) The value of 'r' approaches zero
(b) K = N
(c) K > N
(d) K < N
Answer
(b) K = N
In logistic growth . When the population reaches the carrying capacity () the growth rate becomes zero and the curve flattens into the upper asymptote. The value of does not become zero.
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- 2017 · NEET-UG (India) · 4 marks
Alexander Von Humbolt described for the first time
(a) Ecological Biodiversity
(b) Laws of limiting factor
(c) Species area relationships
(d) Population Growth equation
Answer
(c) Species area relationships
Alexander von Humboldt observed that within a region the species richness increases with the area explored, but only up to a limit. This was the first description of the species-area relationship ().
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- 2018 · NEET-UG (India) · 4 marks
Niche is
(a) all the biological factors in the organism's environment
(b) the physical space where an organism lives
(c) the range of temperature that the organism needs to live
(d) the functional role played by the organism where it lives
Answer
(d) the functional role played by the organism where it lives
An organism habitat is its physical place of living, whereas its niche is the functional role in the ecosystem: what it eats, its interactions, and the resources it uses. Options (b) and (c) describe habitat and a single physical factor, which are only parts of the picture.
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- 2018 · NEET-UG (India) · 4 marks
Natality refers to
(a) Death rate
(b) Birth rate
(c) Number of individuals leaving the habitat
(d) Number of individuals entering a habitat
Answer
(b) Birth rate
Natality is the number of births during a given period in the population, expressed per unit population. Death rate is mortality, while individuals entering and leaving a habitat are immigration and emigration.
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- 2018 · NEET-UG (India) · 4 marks
What type of ecological pyramid would be obtained with the following data?
Secondary consumer : 120 g
Primary consumer : 60 g
Primary producer : 10 g
(a) Inverted pyramid of biomass
(b) Pyramid of energy
(c) Upright pyramid of numbers
(d) Upright pyramid of biomass
Answer
(a) Inverted pyramid of biomass
Biomass increases with trophic level here (10 g producers, 60 g primary consumers, 120 g secondary consumers), so the pyramid is wider at the top, i.e. inverted. Such pyramids occur in aquatic ecosystems where producers (phytoplankton) have a high turnover but low standing crop. An energy pyramid is always upright, and the data are biomass, not numbers.
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- 2018 · NEET-UG (India) · 4 marks
Pneumatophores occur in
(a) Halophytes
(b) Free-floating hydrophytes
(c) Carnivorous plants
(d) Submerged hydrophytes
Answer
(a) Halophytes
Pneumatophores are upward-growing respiratory roots of mangrove plants (halophytes such as Rhizophora and Avicennia) growing in saline, waterlogged, poorly aerated soil. They take in air through lenticel-like pores called pneumathodes.
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- 2018 · NEET-UG (India) · 4 marks
Which one of the following plants shows a very close relationship with a species of moth, where none of the two can complete its life cycle without the other?
(a) Hydrilla
(b) Yucca
(c) Banana
(d) Viola
Answer
(b) Yucca
Yucca and the moth Pronuba show obligate mutualism: the moth pollinates the flower and lays eggs in its ovary, and the larvae feed on some developing seeds. Neither can complete its life cycle without the other.
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- 2018 · NEET-UG (India) · 4 marks
In a growing population of a country,
(a) pre-reproductive individuals are more than the reproductive individuals.
(b) reproductive individuals are less than the post-reproductive individuals.
(c) reproductive and pre-reproductive individuals are equal in number.
(d) pre-reproductive individuals are less than the reproductive individuals.
Answer
(a) pre-reproductive individuals are more than the reproductive individuals.
A growing population has an expanding (broad-based) age pyramid, with the largest share of young, pre-reproductive individuals, then fewer reproductive and fewest post-reproductive individuals.
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- 2018 · NEET-UG (India) · 4 marks
All of the following are included in 'ex-situ conservation' except
(a) Wildlife safari parks
(b) Sacred groves
(c) Botanical gardens
(d) Seed banks
Answer
(b) Sacred groves
Sacred groves are in-situ conservation, since the species are protected in their natural habitat. Wildlife safari parks, botanical gardens and seed banks maintain species outside their natural habitat, which is ex-situ conservation.
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- 2018 · NEET-UG (India) · 4 marks
Which one of the following population interactions is widely used in medical science for the production of antibiotics?
(a) Commensalism
(b) Mutualism
(c) Parasitism
(d) Amensalism
Answer
(d) Amensalism
Antibiotics such as penicillin (from Penicillium) are chemicals secreted by one organism that inhibit another without affecting the producer, which is amensalism (+/0 for the producer, harm to the other). It is not mutualism, commensalism or parasitism.
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- 2018 · NEET-UG (India) · 4 marks
Which of the following organisms are known as chief producers in the oceans?
(a) Dinoflagellates
(b) Diatoms
(c) Cyanobacteria
(d) Euglenoids
Answer
(b) Diatoms
Diatoms are the chief producers in the oceans: they are abundant microscopic photosynthetic algae in phytoplankton. Dinoflagellates are less abundant, and cyanobacteria and euglenoids are minor contributors to marine productivity.
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- 2019 · NEET-UG (India) · 4 marks
Which of the following ecological pyramids is generally inverted?
(a) Pyramid of biomass in a forest
(b) Pyramid of biomass in a sea
(c) Pyramid of numbers in grassland
(d) Pyramid of energy
Answer
(b) Pyramid of biomass in a sea
In the sea the producers are tiny phytoplankton with a fast turnover and low standing biomass, whereas the zooplankton and fish they support have a larger standing biomass, giving an inverted pyramid. Biomass pyramids in forests and numbers in grassland are upright, and energy pyramids are always upright.
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- 2019 · NEET-UG (India) · 4 marks
Which one of the following is not a method of in situ conservation of biodiversity?
(a) Botanical Garden
(b) Sacred Grove
(c) Biosphere Reserve
(d) Wildlife Sanctuary
Answer
(a) Botanical Garden
In situ conservation protects organisms in their natural habitat, as in sacred groves, biosphere reserves, national parks and wildlife sanctuaries. A botanical garden keeps plants outside their natural habitat, so it is an ex situ method.
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- 2020 · NEET-UG (India) · 4 marks
Which of the following regions of the globe exhibits highest species diversity?
(a) Himalayas
(b) Amazon forests
(c) Western Ghats of India
(d) Madagascar
Answer
(b) Amazon forests
The Amazon rain forest has the highest species diversity in the world, with more than 40,000 plant species. Diversity increases from the poles towards the equator. The Western Ghats, Himalayas and Madagascar are hotspots but have fewer species than the Amazon.
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- 2020 · NEET-UG (India) · 4 marks
According to Robert May, the global species diversity is about
(a) 50 million
(b) 7 million
(c) 1.5 million
(d) 20 million
Answer
(b) 7 million
Robert May (1988) estimated global species diversity at about 7 million. The IUCN figure of about 1.5 million is the number of species actually described so far, which is the tempting wrong option (c).
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- 2020 · NEET-UG (India) · 4 marks
Which of the following is not an attribute of a population?
(a) Mortality
(b) Species interaction
(c) Sex ratio
(d) Natality
Answer
(b) Species interaction
Attributes of a population are properties of the group as a whole: natality, mortality, sex ratio, age distribution and density. Species interaction (predation, competition and so on) is a community-level feature, not a population attribute.
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- 2020 · NEET-UG (India) · 4 marks
In relation to gross primary productivity and Net primary productivity of an ecosystem, which one of the following statements is correct?
(a) Gross primary productivity and Net primary productivity are one and same.
(b) There is no relationship between Gross primary productivity and Net primary productivity.
(c) Gross primary productivity is always less than Net primary productivity.
(d) Gross primary productivity is always more than Net primary productivity.
Answer
(d) Gross primary productivity is always more than Net primary productivity.
Net primary productivity is , where is energy lost in plant respiration. Since , GPP is always greater than NPP, so the "same" and "less than" options are wrong.
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- 2020 · NEET-UG (India) · 4 marks
Match the trophic levels with their correct species examples in grassland ecosystem.
(a) Fourth trophic level
(b) Second trophic level
(c) First trophic level
(d) Third trophic level
(i) Crow
(ii) Vulture
(iii) Rabbit
(iv) Grass
Select the correct option:
(a) a-iv, b-iii, c-ii, d-i
(b) a-i, b-ii, c-iii, d-iv
(c) a-ii, b-iii, c-iv, d-i
(d) a-iii, b-ii, c-i, d-iv
Answer
(c) a-ii, b-iii, c-iv, d-i
In a grassland food chain, grass is the producer (first level), the rabbit is the primary consumer (second), the crow is the secondary consumer (third) and the vulture is the tertiary consumer (fourth). Matching each gives a-ii, b-iii, c-iv, d-i.
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- 2023 · NEET-UG (India) · 4 marks
The historic Convention on Biological Diversity, 'The Earth Summit' was held in Rio de Janeiro in the year
(a) 1992
(b) 1986
(c) 2002
(d) 1985
Answer
(a) 1992
The Convention on Biological Diversity was opened for signature at the Earth Summit held in Rio de Janeiro, Brazil, in 1992. The 2002 date belongs to the Johannesburg World Summit on Sustainable Development, a tempting wrong option.
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- 2023 · NEET-UG (India) · 4 marks
In the equation GPP – R = NPP
GPP is Gross Primary Productivity
NPP is Net Primary Productivity
R here is
(a) Respiratory quotient
(b) Respiratory loss
(c) Reproductive allocation
(d) Photosynthetically active radiation
Answer
(b) Respiratory loss
Net primary productivity is gross primary productivity minus the organic matter used by plants in respiration. So , where R is respiratory loss, not respiratory quotient.
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- 2023 · NEET-UG (India) · 4 marks
The thickness of ozone in a column of air in the atmosphere is measured in terms of :
(a) Decibels
(b) Decameter
(c) Kilobase
(d) Dobson units
Answer
(d) Dobson units
Ozone thickness in a column of air is measured in Dobson units (DU), where 1 DU is 0.01 mm of pure ozone at STP. Decibel measures sound, and kilobase is a DNA length unit.
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- 2023 · NEET-UG (India) · 4 marks
Identify the correct statements:
A. Detritivores perform fragmentation.
B. The humus is further degraded by some microbes during mineralization.
C. Water soluble inorganic nutrients go down into the soil and get precipitated by a process called leaching.
D. The detritus food chain begins with living organisms.
E. Earthworms break down detritus into smaller particles by a process called catabolism.
Choose the correct answer from the options given below:
(a) B, C, D only
(b) C, D, E only
(c) D, E, A only
(d) A, B, C only
Answer
(d) A, B, C only
Detritivores fragment detritus, humus is degraded slowly by microbes during mineralisation, and leaching carries soluble nutrients down into the soil. D is wrong because the detritus food chain begins with dead organic matter, and E is wrong because earthworm breakdown is fragmentation, not catabolism.
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- 2023 · NEET-UG (India) · 4 marks
Among 'The Evil Quartet', which one is considered the most important cause driving extinction of species?
(a) Over exploitation for economic gain
(b) Alien species invasions
(c) Co-extinctions
(d) Habitat loss and fragmentation
Answer
(d) Habitat loss and fragmentation
Of the Evil Quartet (habitat loss and fragmentation, over-exploitation, alien species invasions, co-extinctions), habitat loss and fragmentation is considered the most important cause of extinction, for example the loss of tropical rainforest.
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- 2023 · NEET-UG (India) · 4 marks
Which one of the following statements is NOT correct?
(a) Algal blooms caused by excess of organic matter in water improve water quality and promote fisheries
(b) Water hyacinth grows abundantly in eutrophic water bodies and leads to an imbalance in the ecosystem dynamics of the water body
(c) The amount of some toxic substances of industrial waste water increases the organisms at successive trophic levels
(d) The micro-organisms involved in biodegradation of organic matter in a sewage polluted water body consume a lot of oxygen causing the death of aquatic organisms
Answer
(a) Algal blooms caused by excess of organic matter in water improve water quality and promote fisheries
This statement is incorrect. Algal blooms from nutrient enrichment (eutrophication) degrade water quality and cause fish mortality. The other options correctly describe water hyacinth, biomagnification and BOD-related oxygen depletion.
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- 2023 · NEET-UG (India) · 4 marks
Match List I with List II:
List I (Interaction) List II (Species A and B) A. Mutualism I. +(A), O(B) B. Commensalism II. -(A), O(B) C. Amensalism III. +(A), -(B) D. Parasitism IV. +(A), +(B)
Choose the correct answer from the options given below:
(a) A-IV, B-I, C-II, D-III
(b) A-IV, B-III, C-I, D-II
(c) A-III, B-I, C-IV, D-II
(d) A-IV, B-II, C-I, D-III
Answer
(a) A-IV, B-I, C-II, D-III
Mutualism is ; commensalism is ; amensalism is ; parasitism is . This matches option (a).
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- 2023 · NEET-UG (India) · 4 marks
Given below are two statements:
Statement I: Gause's 'Competitive Exclusion Principle' states that two closely related species competing for the same resources cannot co-exist indefinitely and competitively inferior one will be eliminated eventually.
Statement II: In general, carnivores are more adversely affected by competition than herbivores.
In the light of the above statements, choose the correct answer from the options given below:
(a) Both Statement I and Statement II are false.
(b) Statement I is correct Statement II is false.
(c) Statement I is incorrect but Statement II is true.
(d) Both Statement I and Statement II are true.
Answer
(b) Statement I is correct Statement II is false
Gause's competitive exclusion principle is correctly stated in Statement I. Statement II is false because, in general, herbivores and plants are more adversely affected by competition than carnivores.
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Questions from NEET-UG 2013 (India), question paper (NTA NEET-UG 2013 question paper; only questions on topics in Nepal's MBBS entrance syllabus), AIPMT 2014 (NEET-UG, India), Code Q (NTA NEET-UG 2014 question paper; only questions on topics in Nepal's MBBS entrance syllabus), NEET-UG 2015 (India), Re-exam Code A (NTA NEET-UG 2015 question paper; only questions on topics in Nepal's MBBS entrance syllabus), NEET-UG 2016 (India), Phase 1 Code A (NTA NEET-UG 2016 question paper; only questions on topics in Nepal's MBBS entrance syllabus), NEET-UG 2017 (India), Code A (NTA NEET-UG 2017 question paper; only questions on topics in Nepal's MBBS entrance syllabus), NEET-UG 2018 (India), Code PP (NTA NEET-UG 2018 question paper; only questions on topics in Nepal's MBBS entrance syllabus), NEET-UG 2019 (India), Code S2 (NTA NEET-UG 2019 question paper; only questions on topics in Nepal's MBBS entrance syllabus), NEET-UG 2020 (India), Code F1 (September 2020) (NTA NEET-UG 2020 question paper; only questions on topics in Nepal's MBBS entrance syllabus) and NEET-UG 2023 (India), Code F1 Botany (NTA NEET-UG 2023 question paper; only questions on topics in Nepal's MBBS entrance syllabus). Answers are written for this site; check them against your class notes.