Set 2 | Important Ecology MCQs

Correct Answer is A.

• The habitat is the environment where an organism resides, providing essential resources like food, water, air, shelter, and other necessities.
• A biome, on the other hand, is a large ecological community of plants and animals spread over a vast geographic region. The major biomes of the world include forests, grasslands, deserts, and tundras.

Correct Answer is D.

• Ecosystems can be broadly classified into two types: aquatic and terrestrial. Marine ecosystems are the largest, covering approximately 71% of Earth’s surface and holding 97% of the planet’s water.

Correct Answer is A.

• An aquatic ecosystem encompasses the living and non-living components of a water body and the interactions between them. These ecosystems are classified into marine and freshwater ecosystems.
• The marine ecosystem covers about 71% of the Earth’s surface and holds roughly 97% of the planet’s water.

Correct Answer is A.

• Wildlife conservation and the prevention of environmental pollution are essential for maintaining ecological balance, as they help preserve biodiversity, support ecosystem services, and ensure the sustainability of natural resources.
• Healthy ecosystems provide clean air, water, and fertile soil, and regulate climate, which benefits both wildlife and human populations. By protecting endangered species and restoring habitats, we can prevent the loss of biodiversity that could otherwise lead to ecosystem collapse.
• On the other hand, deforestation significantly disrupts ecological balance. It leads to habitat loss for countless species, increases greenhouse gas emissions, and contributes to soil erosion, water cycle disruption, and climate change.
• Forests play a vital role in absorbing carbon dioxide, so their destruction exacerbates global warming. Moreover, deforestation can trigger a decline in species populations, which can have a ripple effect on food chains and other ecological interactions. Addressing deforestation is crucial for sustaining a healthy planet and ensuring the continued functioning of ecosystems.

Correct Answer is A.

• Deforestation is a leading cause of ecological imbalance in India, as it results in the loss of forests, which are critical for maintaining biodiversity, regulating the climate, and supporting local communities. The removal of trees not only destroys wildlife habitats but also increases carbon emissions, contributing to global warming.
• In addition to deforestation, other secondary factors contribute to ecological imbalance in India. Desertification, the degradation of land in arid areas due to factors such as overgrazing and unsustainable farming, is a growing concern.
• Floods and famines, often linked to deforestation and poor land management, further disrupt ecosystems and human livelihoods. Variations in rainfall patterns, driven by climate change and environmental degradation, lead to unpredictable weather conditions, impacting agriculture and water resources. These combined factors exacerbate the ecological challenges facing the country.

Correct Answer is A.

• Lumbering, or the large-scale cutting and harvesting of trees, significantly disturbs the ecological balance. By removing vast areas of forests, lumbering contributes to habitat destruction, loss of biodiversity, and increased carbon emissions, which exacerbate climate change.
• Forests play a crucial role in regulating the Earth’s climate, conserving soil, and maintaining water cycles. When trees are cut down for lumber, the ecosystem loses its ability to absorb carbon dioxide, filter air, and support wildlife, leading to imbalances in local and global ecosystems.
• Additionally, lumbering often leads to soil erosion, as tree roots, which help anchor the soil, are removed. This can cause sediment to enter rivers and lakes, disrupting aquatic ecosystems and reducing water quality.
• The cumulative effects of lumbering weaken the resilience of ecosystems and make them more vulnerable to extreme weather events, such as floods and droughts, further upsetting the ecological balance.

Correct Answer is C.

In an ecosystem, there are four primary trophic levels in the food chain:

1. First Trophic Level – Producers: These are organisms, such as plants and algae, that produce their own food through photosynthesis. They form the base of the food chain.
2. Second Trophic Level – Primary Consumers: These are herbivores that feed on producers. They obtain energy by consuming plant material.
3. Third Trophic Level – Secondary Consumers: These are carnivores that eat primary consumers. They obtain energy by feeding on herbivores.
4. Fourth Trophic Level – Tertiary Consumers: These are omnivores or apex predators that consume secondary consumers and sometimes primary consumers. They are at the top of the food chain and have few natural predators.

In addition to these levels, decomposers play a crucial role in the ecosystem. They feed on all trophic levels, breaking down dead organisms and waste products, and recycling nutrients back into the environment.

Correct Answer is A.

Biotic components are the living elements that shape and influence an ecosystem. They include:

• Producers: These are organisms that create their own food through processes such as photosynthesis. For example, plants are primary producers that form the base of the food chain.
• Consumers: These are organisms that rely on other organisms for energy. They include animals, such as herbivores (which eat plants), carnivores (which eat other animals), and omnivores (which consume both plants and animals). Humans are also consumers as they depend on various organisms for food.
• Decomposers: These organisms break down dead or decaying organisms, recycling nutrients back into the environment. Examples include fungi and bacteria, which play a crucial role in nutrient cycling and ecosystem health.

Correct Answer is C.

• Solar energy is the primary source of energy for ecological systems. It serves as the fundamental driving force behind most ecosystems, powering processes such as photosynthesis in plants.
• Through photosynthesis, producers convert solar energy into chemical energy, which forms the base of the food chain. This energy is then transferred through various trophic levels as consumers and decomposers interact within the ecosystem.
• Solar energy thus plays a crucial role in sustaining life and maintaining ecological balance.

Correct Answer is D.

• The driving force of an ecosystem is solar energy. It fuels primary production through photosynthesis, which forms the foundation of the food chain and supports all other trophic levels.
• By providing the energy necessary for plants and other producers to create organic matter, solar energy underpins the functioning and productivity of the entire ecosystem.