Test: Ecology - UPSC MCQ

Ecology refers to the study of the relationships between organisms and their environment. It encompasses the interactions between living organisms (plants, animals, and microorganisms) and their physical surroundings (air, water, soil, and other factors).

Plants are an example of a biotic component of an ecosystem. Biotic components are the living organisms within an ecosystem, including plants, animals, fungi, and bacteria. In contrast, abiotic components refer to the non-living factors such as temperature, rocks, sunlight, and water.

Herbivore is a primary consumer in an ecosystem. Herbivores are organisms that feed exclusively on plants. They obtain their energy by consuming plant material, making them the first level of consumers in a food chain or food web.

Photosynthesis is the term used to describe the process by which green plants use sunlight to synthesize food from carbon dioxide and water. In this process, plants convert light energy into chemical energy in the form of glucose, releasing oxygen as a byproduct. This process is vital for the production of food and the release of oxygen into the atmosphere.

Solar energy is an example of a renewable resource. Renewable resources are those that can be naturally replenished or regenerated over time, such as solar energy, wind energy, and hydropower. They are considered sustainable alternatives to nonrenewable resources like fossil fuels, which are finite and take millions of years to form.

Ability to colonize disturbed areas is a characteristic of a pioneer species. Pioneer species are the first organisms to colonize and establish themselves in barren or disturbed ecosystems, such as after a volcanic eruption or a wildfire. They are typically hardy and can tolerate harsh conditions, helping to prepare the environment for other species to follow.

Biodiversity refers to the variety of life on Earth, including the diversity within species, between species, and within ecosystems. It encompasses genetic diversity, species diversity, and ecosystem diversity. Biodiversity is important for the stability and functioning of ecosystems, as well as for the provision of ecosystem services that are essential for human well-being.

Carbon dioxide is a greenhouse gas. Greenhouse gases are those that trap heat in the Earth's atmosphere, contributing to the greenhouse effect and global warming. Other greenhouse gases include methane, nitrous oxide, and water vapor. Carbon dioxide is primarily released through human activities such as burning fossil fuels, deforestation, and industrial processes.

Sunlight is the primary source of energy for most ecosystems. Sunlight provides the energy needed for photosynthesis in plants, which forms the basis of the food chain or food web. Producers, such as plants and algae, convert sunlight into chemical energy, and this energy is then transferred to consumers through their consumption of plants or other animals.

Beaver is an example of a keystone species. Keystone species are those that have a disproportionately large impact on their ecosystem relative to their abundance. Their presence or absence can significantly affect the structure and functioning of the ecosystem. In the case of beavers, their dam-building activities create wetland habitats that benefit a wide range of other species and can even alter the flow of rivers.

Recycling is the term used to describe the process of converting waste materials into reusable materials. It involves collecting and processing waste materials such as paper, plastic, glass, and metal to create new products. Recycling helps conserve resources, reduce energy consumption, and minimize waste disposal in landfills.

Petroleum is an example of a nonrenewable resource. Nonrenewable resources are those that are finite and cannot be replenished within a human lifespan. They are formed over millions of years through geological processes and include fossil fuels like oil, coal, and natural gas. Once these resources are depleted, they cannot be replaced.

Carbon emissions are the main cause of the greenhouse effect. When carbon dioxide and other greenhouse gases are released into the atmosphere through human activities, such as burning fossil fuels and deforestation, they trap heat from the sun, leading to a rise in global temperatures. This phenomenon is known as the greenhouse effect and is a significant driver of climate change.

 Coral reef is an example of a natural ecosystem. Natural ecosystems are those that occur without significant human intervention and have developed over long periods of time. Coral reefs are diverse marine ecosystems that provide habitats for numerous species and are characterized by the presence of corals, fish, and other marine organisms.

Climate is the term used to describe the long-term average weather conditions in a specific area. It includes factors such as temperature, precipitation, humidity, wind patterns, and other atmospheric conditions. Climate is determined by various factors, including latitude, altitude, proximity to water bodies, and prevailing air masses.

Mutualism between bees and flowers is an example of a symbiotic relationship. Symbiotic relationships are interactions between different species that live in close proximity to each other. Mutualism is a type of symbiotic relationship in which both species benefit. In the case of bees and flowers, bees obtain nectar as a food source, while flowers are pollinated in the process, facilitating reproduction.

Terracing is a method of reducing soil erosion. It involves creating flat or gently sloping steps or terraces on hilly or steeply sloping land. By constructing these terraces, water runoff is slowed down, reducing the erosive force and allowing water to infiltrate the soil more effectively. Terracing helps prevent soil erosion and supports agricultural practices on sloping terrain.

Species diversity is the term used to describe the variety of different species in an ecosystem. It takes into account both the number of species present (species richness) and the relative abundance of each species (species evenness). Species diversity is an important indicator of the health and stability of an ecosystem.

Stable population sizes are a characteristic of a sustainable ecosystem. A sustainable ecosystem is one that can persist over time without degrading its natural resources or compromising the well-being of its inhabitants. It is characterized by balanced population sizes, efficient resource use, and the maintenance of biodiversity. High pollution levels, overexploitation of resources, and loss of biodiversity are not consistent with a sustainable ecosystem.

The main process that returns water to the atmosphere in the water cycle is evaporation. The water cycle, also known as the hydrological cycle, involves the continuous movement of water between the atmosphere, land, and oceans. It includes processes such as evaporation, condensation, precipitation, and runoff. Evaporation occurs when water changes from a liquid state to a gaseous state, rising into the atmosphere where it can later condense and form clouds before precipitating back to the Earth's surface. The water cycle plays a crucial role in regulating Earth's climate by distributing heat and moisture around the planet.