Important MCQs on Ecology With Explanation

Ans. (c) Habitat

Explanation: In ecology, the term habitat refers to the collection of resources, physical and biological variables that exist in a certain location to help a species survive and reproduce. The habitat of a species may be thought of as the physical expression of its biological niche. Habitats ebb and flow over time. Changes might be gradual or abrupt, natural or created by humans. Some human activities can be devastating to some habitats, causing dramatic changes that may lead to their collapse, while others can recreate ecosystems, as has happened in Europe's numerous biodiversity-rich semi-natural environments. 

Ans. (d) Biomass

Explanation: Biomass is organic material that is renewable and originates from plants and animals. Biomass is a renewable energy source since organic matter may be replenished in a relatively short period of time. While biomass energy can come from a variety of places, there are two main ways to use it to create electricity: burning and decomposition. The burning of both live and dead plants is known as biomass burning. It encompasses both human-initiated vegetation burning for land clearance and land-use change and natural, lightning-caused fires.

Ans. (a) Heliophytes

Explanation: Sunstroke plants, also known as heliophytes, are suited to an environment with high levels of insolation due to their ability to build and maintain their own structure (metabolism). Mullein, ling, thyme, soft velcro, white clover, and most roses are examples of solar plants. They can be found on open terrain, rocks, meadows, alpine pastures and grasslands, and other areas with lengthy solar exposures. Coarse, small leaves with hairy and waxy protection against excessive solar radiation and water loss are unique to the plant. To prevent hazardous effects, chloroplasts feature defensive elements such as carotenoids and enzymes, as well as a buildup of reactive oxygen species (ROS).

Ans. (c) Commensalism

Explanation: In biology, commensalism is a connection between members of two species in which one derives food or other advantages from the other without hurting or benefitting the latter. The commensal- the species that benefit from the relationship may acquire nourishment, shelter, support, or movement from the unaffected host species. A bigger host and a smaller commensal are frequently seen in a commensal relationship. The host organism is usually unaffected by the interaction, however, the commensal species may show substantial morphological adaptation. Mutualism, on the other hand, is a partnership in which both species benefit.

Ans. (c) Stratification

Explanation: The act of classifying data, people, and things into discrete groups or levels is known as stratification. It's a method for analysing data that are utilised in conjunction with other technologies. The significance of data might be difficult to perceive when data from several sources or classifications have been thrown together.

Ans. (b) Carbon Dioxide

Explanation: Carbon dioxide (CO₂) is a significant heat-trapping (greenhouse) gas that is emitted by human activities like deforestation and fossil fuel combustion, as well as natural processes like respiration and volcanic eruptions. Under normal circumstances, all animals, fungi, and microbes that rely on live or decaying plants for sustenance create this colourless, odourless gas during respiration. The absorption of carbon dioxide (CO₂) from the atmosphere causes ocean acidification, which is the continual decline in the pH value of the Earth's seas. Human actions, namely the combustion of fossil fuels, are the primary cause of ocean acidification. As a result, the amount of carbon dioxide absorbed by the ocean rises.

Ans. (c) Limnetic zone

Explanation: A lake's limnetic zone is the open, well-lit surface waters distant from the shore. This area of open water is surrounded by littoral zone vegetation and is above the profundal zone. This is the lake's major photosynthetic body. This zone generates the oxygen and food that the lake's consumers require. The illuminated surface waters in a region where the lake bottom is too deep and unlit to sustain rooted aquatic plants can be characterised. A variety of phytoplankton, including algae and cyanobacteria, as well as zooplankton, tiny crustaceans, and fish, live in this region. In this region of the lake, the majority of photosynthesis occurs.

Ans. (a) Ecotype

Explanation: An ecotype is a variety with phenotypic characteristics that are too little or insignificant to be classed as a subspecies. Diverse environments such as meadows, forests, swamps, and sand dunes provide biological niches for these different varieties to occur in the same geographic location. When comparable ecological circumstances exist in widely distant sites, a similar ecotype may also exist in other locations. An ecotype is distinct from a subspecies, which can be found in a variety of locales. Ecotypes in animals have distinct traits due to the impact of a relatively local environment. As a result, ecotypes do not have a taxonomic rank.

Ans. (b) Plankton

Explanation: Plankton is a varied group of creatures that live in water (or air) and are unable to swim against the stream (or wind). Plankters are the individual creatures that makeup plankton. Many tiny and big aquatic species, such as bivalves, fish, and whales, rely on them for sustenance in the water. Plankton is the unsung hero of many ecosystems, supplying sustenance for anything from small bivalves to whales. Plankton creatures, despite their minuscule size, play an important role in marine ecosystems. They serve as a foundation for the entire marine food web.

Ans. (a) The generation of toxins by one species inhibits the development of another.

Explanation: Allelopathy is a widespread biological occurrence in which one organism creates biochemicals that affect other species' growth, survival, development, and reproduction. Allelochemicals are biochemicals that have either positive or negative impacts on target organisms. Plant allelopathy is one of the modes of interaction between receptor and donor plants, and it can have either positive (e.g., for agricultural management, such as weed control, crop protection, or crop re-establishment) or negative (e.g., for weed control, crop protection, or crop re-establishment) or negative (e.g., for weed control, crop protection, or crop re-establishment) or negative (e.g., for (e.g., autotoxicity, soil sickness, or biological invasion).

Ans. (a) Neuston

Explanation: The unattached creatures that live at the air-water interface, such as floating plants, are known as Neuston. Some creatures, such as striders, spend most of their time on top of the air-water interface, whereas others spend the majority of their time below it. Pleuston refers to creatures that live in the thin surface layer that exists at the air-water interface of a body of water, whereas neuston refers to organisms that float on top of the water (epineuston) or reside immediately under the surface (hyponeuston).