Ecology & Ecosystems — Set 1
Environment · पारिस्थितिकी और पारिस्थितिकी तंत्र · Questions 1–10 of 60
Which of the following terms describes the functional role and position of a species in its ecosystem?
Correct Answer: A. Ecological Niche
An ecological niche encompasses how a species responds to the distribution of resources and competitors. It includes the species' specific biological requirements and its interactions with the environment. Every species in a healthy ecosystem generally occupies a unique niche.
What is the primary source of energy for most terrestrial and aquatic ecosystems?
Correct Answer: A. Solar radiation
Solar radiation provides the necessary energy for photosynthesis by producers like plants and algae. This light energy is converted into chemical energy that flows through various trophic levels. Without the sun, most life forms on Earth would not be able to sustain themselves.
Which of the following is an example of an abiotic component of an ecosystem?
Correct Answer: D. Soil pH
Soil pH is a non-living chemical factor that influences the types of plants that can grow in an area. Abiotic components include physical and chemical elements like temperature, sunlight, and water. These factors determine the structure and survival of the biotic community.
The transition zone between two distinct ecosystems is known as a/an?
Correct Answer: A. Ecotone
An ecotone is an area where two communities meet and integrate, such as a marshland between a river and land. These zones often harbor a higher number of species compared to the adjoining ecosystems. This phenomenon of increased diversity is commonly known as the edge effect.
Which organism occupies the first trophic level in a typical grazing food chain?
Correct Answer: D. Primary Producers
Primary producers, such as green plants, form the base of the food chain by creating their own food. They use energy from sunlight to synthesize organic compounds from inorganic materials. All subsequent trophic levels depend on the energy captured at this first level.
What happens to the total available energy as it moves from one trophic level to the next higher level?
Correct Answer: A. It decreases
Energy decreases as it moves up a food chain because much of it is lost as heat during metabolic processes. Generally, only about 10 percent of the energy is passed on to the next level. This limit on energy transfer explains why food chains rarely exceed four or five levels.
In an ecological pyramid of numbers, which ecosystem can sometimes show an inverted pyramid shape?
Correct Answer: D. Tree Ecosystem
A single large tree can support thousands of small insects, resulting in an inverted pyramid of numbers. In such cases, the base is narrow (one producer) and the upper levels are wider (many consumers). This highlights that the number of organisms does not always correlate with energy flow.
Which of the following processes is primarily responsible for the 'cycling of nutrients' in an ecosystem?
Correct Answer: A. Decomposition
Decomposition by fungi and bacteria breaks down dead organic matter into simpler inorganic nutrients. These nutrients are then returned to the soil or water to be reused by producers. This recycling process is vital for maintaining the fertility and sustainability of ecosystems.
A sequence of organisms through which nutrients and energy pass is called a?
Correct Answer: D. Food Chain
A food chain represents a linear pathway of energy transfer between species. It starts with a producer and ends with a top predator or decomposer. In real nature, multiple interconnected food chains form a more complex system called a food web.
Which type of ecological pyramid is always upright and can never be inverted?
Correct Answer: A. Pyramid of Energy
The pyramid of energy is always upright because energy is lost as heat at every level. It represents the total amount of energy used by different trophic levels per unit area and time. This follows the fundamental laws of thermodynamics governing energy flow.