Ecology & Environment MCQ Quiz - Objective Question with Answer for Ecology & Environment - Download Free PDF

Key Points

• A food chain represents the flow of energy in an ecosystem, starting from producers and moving to top consumers.
• Grass (II) is the producer, which is consumed by the primary consumer, Locust (V).
• The Locust (V) is eaten by the secondary consumer, Frog (I), which is then consumed by the tertiary consumer, Snake (III).
• The final consumer or apex predator in this chain is the Eagle (IV).

Important Points

• Producers: Organisms like grass (plants) that produce energy through photosynthesis.
• Primary Consumers: Herbivores such as locusts that feed on producers.
• Secondary Consumers: Carnivores like frogs that feed on primary consumers.
• Tertiary Consumers: Higher-level carnivores like snakes that feed on secondary consumers.
• Apex Predators: Top predators like eagles that have no natural predators in this chain.

Additional Information

• Food Chain: A food chain is a linear sequence of organisms where nutrients and energy pass as one organism eats another. Energy flows from producers to consumers.
• Energy Flow: Energy decreases as it moves up the food chain due to the 10% rule, where only 10% of energy is transferred to the next trophic level.

Key Points

• Pitcher plants are carnivorous plants that trap and digest insects, including mosquitoes, as part of their nutrient acquisition process.
• The plant's specialized pitcher-shaped leaves contain a digestive fluid that breaks down the prey into usable nutrients.
• Pitcher plants are commonly found in nutrient-poor environments, such as bogs and marshes, where they rely on insects for supplementary nutrition.
• These plants use nectar, bright colors, and scents to lure mosquitoes and other insects into their trap.
• Species like Nepenthes and Sarracenia are well-known examples of pitcher plants capable of trapping mosquitoes.

Additional Information

• Carnivorous Plants:
  • These plants derive some or most of their nutrients from trapping and consuming animals, primarily insects.
  • Examples include Venus Flytrap, Sundew, Pitcher Plant, and Bladderwort.
  • They are typically found in habitats with low nutrient availability, such as acidic soils.
• Nepenthes:
  • A genus of tropical pitcher plants found in Southeast Asia, Madagascar, and Australia.
  • Known for producing large pitchers that trap insects and sometimes even small vertebrates.
  • The digestive fluid inside the pitcher contains enzymes and bacteria that help break down prey.
• Sarracenia:
  • A genus of pitcher plants native to North America, commonly referred to as "North American Pitcher Plants."
  • Sarracenia species use a combination of nectar, scent, and coloration to attract insects, including mosquitoes.
  • The plant's downward-facing hairs prevent trapped insects from escaping.

The correct answer is Biodiversity, Endemic species.

Key Points

• Biodiversity refers to the variety of living organisms, including plants, animals, and microorganisms, found in a specific area or ecosystem.
• Endemic species are species that are found exclusively in a particular geographical location and nowhere else in the world.
• Biodiversity is critical for maintaining ecosystem balance, resilience, and providing ecological services such as pollination, water purification, and climate regulation.
• Examples of endemic species in India include the Nilgiri Tahr and the Malabar Civet, which are restricted to specific regions of the country.

Additional Information

• Levels of Biodiversity:
  • Genetic Diversity: Variation within the genetic makeup of individuals within a species.
  • Species Diversity: The variety of species within a given ecosystem or region.
  • Ecosystem Diversity: The diversity of habitats, ecosystems, and ecological processes within a region.
• Importance of Endemic Species:
  • Endemic species play a significant role in the ecological balance of their unique habitats.
  • They often indicate the health of an ecosystem and are sensitive to environmental changes.
• Threats to Biodiversity:
  • Deforestation, habitat loss, pollution, and climate change are major factors impacting biodiversity.
  • Invasive species and overexploitation of resources also pose significant threats to both biodiversity and endemic species.
• Conservation Efforts:
  • Protected areas like national parks, wildlife sanctuaries, and biosphere reserves are established to safeguard biodiversity.
  • Programs such as the Global Biodiversity Framework and Convention on Biological Diversity (CBD) aim to promote sustainable development while conserving biodiversity.

The correct answer is By enabling species to survive in different environments.

Key Points

• Adaptation allows species to thrive in various environmental conditions, which supports their survival and the overall health of ecosystems. (Source: National Geographic)
• By enabling species to survive, adaptation contributes to the maintenance of genetic diversity, which is crucial for resilience against environmental changes. (Source: World Wildlife Fund)
• Adaptations such as camouflage, mimicry, and behavioral changes help species avoid predators and find food, further aiding their survival. (Source: Smithsonian Institution)
• Adaptation helps in the establishment of stable populations, which are vital for ecosystem balance and biodiversity conservation. (Source: Conservation Biology Journal)

Additional Information

• Biodiversity
  • Biodiversity refers to the variety of life on Earth, including species, ecosystems, and genetic diversity. (Source: United Nations)
  • High biodiversity increases ecosystem productivity and stability. (Source: International Union for Conservation of Nature)
  • Conservation of biodiversity ensures the availability of resources for future generations. (Source: Environmental Protection Agency)
• Genetic Diversity
  • Genetic diversity within species is crucial for adaptability and survival. (Source: Nature Journal)
  • It helps populations resist diseases and respond to environmental changes. (Source: Genetic Society)
  • Loss of genetic diversity can lead to extinction. (Source: World Health Organization)
• Adaptation Mechanisms
  • Adaptation mechanisms include physiological, behavioral, and structural changes. (Source: Encyclopedia of Life)
  • Examples include changes in reproductive strategies, migration patterns, and physical traits. (Source: National Geographic)
  • These mechanisms help species cope with environmental stressors. (Source: Environmental Science Journal)
• Conservation Strategies
  • Conservation strategies include protected areas, wildlife corridors, and habitat restoration. (Source: World Wildlife Fund)
  • In-situ and ex-situ conservation methods are employed to preserve biodiversity. (Source: Conservation Biology Journal)
  • Community involvement and education are essential for effective conservation. (Source: United Nations)

The correct answer is Option 1.

Key Points

• Plants in the desert are adapted to survive with minimal water due to harsh environmental conditions such as high temperatures, low humidity, and scarce rainfall.
• Cactus plants have spines instead of leaves, which significantly reduce water loss by minimizing the surface area for transpiration.
• Desert plants often have specialized adaptations like water-storing tissues (succulence), deep root systems, and waxy coatings on surfaces to retain water.
• Both the assertion and reason are correct, and the reason explains the assertion accurately, as spines help desert plants conserve water efficiently.
• Desert plants like cacti exhibit xerophytic adaptations to thrive in arid environments.

Additional Information

• Transpiration: The process by which plants lose water vapor through stomata; minimized in desert plants to conserve water.
• Xerophytes: Plants adapted to survive in environments with minimal water availability, such as deserts.
• Succulence: A characteristic of desert plants where they store water in their stems, leaves, or roots for prolonged periods.
• CAM Photosynthesis: A specialized photosynthetic pathway in desert plants that minimizes water loss by opening stomata at night instead of during the day.
• Other adaptations include deep taproots to access underground water and waxy coatings on stems to reduce water evaporation.

The correct answer is Option 2. 

Key Points

•  Increasing the efficiency of the combustion process can indeed help reduce the pollution caused by burning fossil fuels. Here are a few ways in which efficiency improvements can be achieved:
  • Advanced Combustion Technologies: Utilizing advanced combustion technologies such as pre-combustion chambers, staged combustion, and optimized fuel-air mixing can enhance combustion efficiency. These methods ensure that fuel is burned more completely, reducing the production of pollutants.
  • Fuel Quality: Using higher-quality fuels with lower impurities and better combustion properties can improve combustion efficiency and reduce emissions. This includes using cleaner-burning fuels such as low-sulfur diesel or natural gas instead of coal or heavy oils.
  • Cogeneration and Combined Heat and Power (CHP) Systems: Cogeneration or CHP systems produce both electricity and useful heat from the same energy source. By capturing waste heat from power generation and utilizing it for heating or other industrial processes, these systems improve overall energy efficiency, reducing the need for separate fuel burning and associated emissions.
  • Energy Efficiency Measures: Implementing energy efficiency measures in industrial processes, buildings, and transportation can reduce the overall energy demand. By using energy more efficiently, the need for burning fossil fuels can be minimized, thereby lowering pollution levels.
  • Carbon Capture and Storage (CCS): CCS technologies capture carbon dioxide (CO2) emissions from power plants and industrial facilities and store them underground or use them for other purposes. While not directly increasing combustion efficiency, CCS can help reduce greenhouse gas emissions and mitigate the environmental impact of burning fossil fuels.
• It is important to note that while increasing combustion efficiency can reduce pollution per unit of energy generated, it does not eliminate the fundamental environmental concerns associated with the combustion of fossil fuels.
• Transitioning to cleaner and renewable energy sources remains crucial for achieving significant reductions in pollution and combating climate change.

The correct answer is zooplankton.

Key Points

• Although there may be some fish that consume phytoplanktons, the main consumers in a lake environment are zooplanktons. Zooplankton is thus the dominant second trophic level in a lake environment.
• The majority of zooplankton species are tiny, microscopic organisms. a single-celled protist that primarily consumes bacteria, for instance. Nonetheless, some zooplankton species can grow fairly large such as jellyfish, arrow worms, etc.
• They are the main consumers because they consume producers like phytoplankton, which are then consumed by small fish (secondary consumers).

Additional Information

•  Food Chain
  • A food chain demonstrates the relationship of feeding between several creatures in a specific habitat or ecosystem.
  • The energy flow from the sun to producers, from producers to consumers, and from consumers to decomposers like fungi is demonstrated by a food chain.
  • They also demonstrate how animals rely on other living things for nourishment.

The correct answer is i - b, ii - c, iii - d, iv - a.

Key Points

The trophic levels represent the hierarchical levels in an ecological food chain, indicating the position of organisms based on their feeding relationships. Here's the explanation for the correct match:

• First trophic level - phytoplankton:
  • The first trophic level typically consists of primary producers that convert sunlight into energy through photosynthesis.
  • Phytoplankton are microscopic plants that form the base of aquatic food chains.
• Second trophic level - zooplankton:
  • The second trophic level comprises primary consumers that feed on the primary producers.
  • Zooplankton, which includes tiny animals, consume phytoplankton, placing them at the second trophic level.
• Third trophic level - fishes:
  • The third trophic level involves secondary consumers that feed on primary consumers.
  • In aquatic ecosystems, fishes are often positioned at the third trophic level as they consume zooplankton or other smaller organisms.
• Fourth trophic level - human:
  • The fourth trophic level represents tertiary consumers, which are higher-order predators.
  • Humans, being omnivores or carnivores, are often placed at the fourth trophic level in food chains when they consume animals from lower trophic levels.​ 

Key Points

Ecotone - 

• An ecotone is a transition area between two biomes.
• It is where two communities meet and integrate.
• It may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and grassland ecosystems).
• Grasslands represent an ecotone and are found between forests on one side and deserts on the other.
• They are subjected to the greater variation of temperature, moisture, wind and light intensity of the sun.

Explanation:

The correct option is Energy.

An ecological pyramid is a pictorial representation of the relationship between different organisms in an ecosystem.

Pyramid of numbers:

• It depicts the numbers of individual organisms at different trophic levels of the food chain.
• It is helpful to calculate the changes observed in the number of organisms in each trophic level.
• We can identify which level is in the endangered zone and need to be saved. But its limitation is we cannot count a number of all organisms accurately.

Pyramid of Biomass:

• Biomass is the dry weight of the organism.
• Pyramid of biomass indicates a decrease of biomass in each tropical level from base to apex.
• With higher tropical level biomass decreases for ecosystem on land and its inverse for an aquatic ecosystem where biomass increases with higher trophic level.

Pyramid of Energy:

An energy pyramid shows how much energy is needed as it flows upwards to support the next trophic level. Here the pyramid is always upward.

Hence, Pyramid of energy is the correct option.

The correct answer is Saprotropic.

Key Points

• Saprotrophic nutrition is the mode of nutrition in which organisms obtain nutrients by decomposing dead and decaying organic matter.
• Saprotrophs, also known as decomposers, secrete digestive enzymes to break down complex organic compounds into simpler substances.
• They absorb the nutrients from the decomposed matter, playing a vital role in recycling nutrients back into the ecosystem.
• Examples of saprotrophs include fungi (such as mushrooms and moulds) and certain bacteria.

Additional Information

• Autotrophic:
  • Autotrophic nutrition is the mode of nutrition in which organisms can synthesize their own food using inorganic substances and an external energy source.
  • Autotrophs convert sunlight or inorganic compounds into organic compounds through photosynthesis or chemosynthesis.
  • They include green plants, algae, and some bacteria.
  • Autotrophs are primary producers in food chains, serving as a source of energy for heterotrophs.
• Heterotrophic:
  • Heterotrophic nutrition is the mode of nutrition in which organisms obtain their food by consuming organic matter produced by other organisms.
  • Heterotrophs cannot synthesize their own food and rely on consuming plants, animals, or other organic materials for nutrients.
  • Examples of heterotrophs include animals, fungi (except for a few species), and most bacteria.
  • Heterotrophs play important roles as consumers and decomposers in food chains and nutrient cycles.
• Monostrophic:
  • A monographic diet, also known as the mono diet or single-food diet, involves eating only one food item or one type of food.
  • Examples of monotrophic diets include consuming solely potatoes or apples or restricting oneself to fruits or meats.
  • Monotrophic diets may be followed for reasons such as food faddism, crash dieting, initiating an elimination diet, or exploring extreme forms of alternative medicine.

Key Points

• Food chain - is a linear sequence of flow of energy takes place between different organisms that are related to each other by the food they consume.

• Food web - is an interconnection of different food chains in an ecosystem.

• Both food chains and food webs outline who eats whom in an ecosystem.
• The organisms are classified into different categories according to their feeding order.
  • Producers - synthesize food from solar energy. This covers all photosynthesizing plants and algae.
  • Primary consumers - come immediately after producers and comprise herbivores that feed on the producers directly.
  • Secondary consumers - feed on primary consumers and hence comprise of carnivores.
  • Decomposers - break down dead, decaying organisms into simpler inorganic substances. E.g. - Fungi.

Important Points

• Scavengers - are carnivorous organisms that feed on the dead and decaying flesh of an animal.
• They differ from other carnivores because they do not hunt.
• Examples - Vultures, Hyenas, Jackals, Crows.

Additional Information

• There are two main types of food chains:
  • Grazing - These food chains start with the producers and are the major system of energy flow in aquatic ecosystems.
  • Detritus - The starting point is dead organic matter from other food chains and is the major energy flow system in terrestrial ecosystems.

The correct answer is Phytoplankton.

Key Points

• Phytoplanktons are microscopic plants found on the topmost layer of the water surface.
• They are the producers of the aquatic ecosystem.
• They absorb the sunlight to make their food and are consumed by primary consumers. Example: Algae and diatoms.

Additional Information

• Zooplankton is small animals like crustaceans or microscopic animals like Meroplanktons, the primary consumers of the aquatic ecosystem.
• Their food is phytoplankton and they are in turn consumed by secondary consumers.
• Aquatic insect
  Aquatic insects are generally secondary consumers of the aquatic ecosystem feeding on zooplankton and phytoplankton.
• small fishes
  • They are tertiary consumers, feeding upon small insects and zooplankton.

The correct answer is Water Vapour.

Key Points

•  Greenhouse gasses
  • A greenhouse gas, often known as a greenhouse gas (GHG or GhG), is a gas that creates the greenhouse effect by absorbing and radiating heat infrared light.
  • Water vapour (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone are the planet's main greenhouse gases (O3).
  • Without greenhouse gases, the average surface temperature of the Earth would be closer to -18 °C (0 °F) than it is today, which is 15 °C (59 °F).
  • Greenhouse gases are found in the atmospheres of Venus, Mars, and Titan.

Additional Information

• Water Vapour 
  • Water vapour, or aqueous vapour are all terms for the gaseous state of water.
  • It is a particular kind of water condition inside the hydrosphere.
  • Water vapour can be created by the boiling or evaporation of liquid water as well as by the sublimation of ice. 
  • Water vapour is continuously produced by evaporation and eliminated by condensation in a normal atmosphere.
  • It causes convection currents that can result in clouds since it is less dense than the majority of the other air constituents.

Important Points

•  Carbon dioxide
  • The most significant contributor to the warming effect, accounting for 64% of the total.
  • Carbon dioxide is long-lived in the atmosphere, with 40% remaining after 100 years, 20% after 1,000 years, and 10% after 10,000 years.
• Methane
  • The second-largest contributor, accounting for 19% of the total.
  • Methane is more potent than carbon dioxide, with a global warming impact that's almost 30 times greater over 100 years.
• Chlorofluorocarbons (CFCs)
  • The third-largest contributor, accounting for 8.1% of the total.
  • CFCs were widely used in the mid-1900s, but they are still long-lived in the atmosphere.
• Nitrous oxide
  • A powerful greenhouse gas with a GWP that's around 270 times that of carbon dioxide.
  • It remains in the atmosphere for a little more than a century. 
• Other greenhouse gases include:
  • Fluorinated gases
  • Hydrochlorofluorocarbons (HCFCs)
  • Hydrofluorocarbons (HFCs)
  • Perfluorocarbons (PFCs)
  • Sulfur hexafluoride (SF6)
  • Nitroge n triflouride (NF3)

Important Points

• In simple words, 'eating' refers to the process of taking the food inside the body, breaking it into smaller parts and then digesting it.
• The digested forms of food are then absorbed by the body to obtain energy.
• This mode of nutrition is known as holotrophic or holozoic nutrition.
• It involves the process of ingestion, digestion and egestion.

Key Points

• Organisms are divided into autotrophs and heterotrophs based on their nutrition.
• Autotrophs do not depend on other organisms for food and are divided into 2 types:
  • Photosynthetic - are those organisms that can make their own food in presence of sunlight. Example - Plants.
  • Chemosynthetic - or chemotrophs can obtain their energy from inorganic substances. Example - Sulphur bacteria
• Heterotrophs depend on other organisms for food and can be divided into 3 types:
  • Holotrophic -  or holozoic organisms take the food inside their body, break it down into smaller parts and then it gets digested and absorbed by the body to get energy. Example - Human.
  • Parasitic - are those organisms which live on or in the body of other organisms called hosts, from where they obtain their food. Example - Lice, tapeworms.
  • Saprotrophic - obtain their food from dead and decaying organisms. Example - Fungi.