MCQ Ecosystem: Introduction & Explanation

Ans: (d) All are correct

Explanation: The man-made ecosystem is not very stable because people only make what they need and what helps them. For example, people make farmland in order to grow food. They are also less effective and have fewer kinds of things to offer. Because of this, they are more likely to be affected by drought, flooding, and diseases.

Ans: (d) Is auto operated

Explanation: Natural ecosystems are those that are made by the forces of nature.

All of the organisms in such an ecosystem live together in peace and depend on each other in some ways.

A natural ecosystem doesn't need anyone else to work. It is run equally by all of the parts that make up the ecosystem.

The population of different living things that make up an ecosystem is the unit of a natural ecosystem.

Ans: (d) the apex of the food pyramid

Explanation: Green plant, bug (grasshopper), frog, snake, and peacock. In the food chain, the green plant is the main source of food because it uses sunlight to make food.

The grasshopper is the most important consumer because it eats the green plant directly. The second consumer is the frog, which eats the grasshopper. The snake, which eats mostly meat, eats the frog. The peacock is the third carnivore because it eats snakes, which are the main meat-eaters.

Food chain

Ans: (a) Producers, consumers and decomposers

Explanation: An ecosystem is made up of different groups of plants, animals, and microorganisms, as well as their physical and chemical surroundings. It has two main parts: biotic, or living, parts and non biotic, or nonliving, parts. Biotic components include producers, consumers, and decomposers. Air, water, and land are all nonliving things.

Ans: (a) Solar radiation/light 

Explanation: Less than half of the sunlight that hits a plant is photosynthetically active radiation (PAR). Only 2% to 10% of PAR can be taken in by plants. So, the amount of light and heat from the sun is what limits the primary productivity of the ecosystem.

Ans: (b) Homeostasis

Explanation: A biological equilibrium is another name for homeostasis. Homeostasis is the process by which different parts of an ecosystem work together to keep a biological balance. It changes over time and doesn't stay the same. A number of things keep the balance in place. These include the amount of waste that can be recycled and how much the environment can hold.

Ans: (d) Ocean

Explanation: Ocean ecosystems are the most stable. Other terrestrial ecosystems also change and have different kinds of living things come and go. But the oceans stay the same for a very long time. Mountains, deserts, and forests are made and destroyed by natural geological processes and human actions, but the oceans have stayed the same over the long history of the Earth. Oceans have a lot of water in them, so small changes don't make them move much.

Ans: (c) is the rate of conversion of light to chemical energy in an ecosystem.

Explanation: Gross primary productivity, or GPP, is the rate at which producers take in energy or make organic matter per unit of time and space. It is the same as total photosynthesis and shows how well producers can use solar energy to make living things.

Ans: (c) Decomposers and scavengers

Explanation: A food chain is a series of plants and animals that are linked because one eats the other for food. It is made up of people who make things, people who use things, and people who break things down. Plants make food. The primary consumers are the herbivores, and the secondary consumers are the carnivores. Decomposers and scavengers break down dead organic matter and release energy back into the environment. So, they are sometimes called "nature's cleaners." They are at the very top of the pyramid.

Ans: (a) Detritus that is high in lignin and chitin decomposes more slowly than detritus that is high in nitrogen and water-soluble materials, such as sugars.

Explanation: If there is a high concentration of lignin and chitin in the detritus, the rate of decomposition will be slower. On the other hand, the rate of decomposition will be faster if there is a high concentration of nitrogen and water-soluble compounds like sugars. 

Ans: (a) Warm and moist environment favor decomposition whereas low temperature and anaerobiosis inhibit decomposition

Explanation: The rate at which organic matter breaks down is affected both directly and indirectly by how much water is in the soil. In a roundabout way, a wet soil makes it take longer for things to break down because the water fills the soil's air spaces, leaving the microbes without oxygen. But all living things also need water, so a soil that is too dry slows down the breakdown of organic matter because the microorganisms in the soil need water to live. Soils that aren't always wet or dry, like a garden that you water once a week, will help organic matter break down faster.

Ans: (d) 2 – 10%

Explanation: About 1% of the energy that comes from the sun, or 2% of PAR, is used by photosynthetic organisms to make organic matter (Gross primary productivity). About 20% of it is used up by respiration, so the net amount of energy taken in is 0.8% of incident radiation or 1.6% of PAR.

Ans: (b) Decomposers

Explanation: Decomposers are saprotrophs that break down dead organic matter by releasing digestive enzymes into the environment.

Decomposers are also called producers because they break down organic matter.

They are also called mineralisers because they get minerals out of dead plants and animals.

Bacteria and fungi, which are both types of microorganisms, usually eat dead and decaying organic matter and break it down.

Ans: (a) always open

Explanation: A system can be open or closed, according to the laws of thermodynamics. An ecosystem is an open system, which means that energy and nutrients move back and forth between the environment and the living things in it. In a closed ecosystem, one organism's waste is used by another organism, such as a decomposer.

Ecosystem 

Ans: (c) low stability and low resilience

Explanation: The diversity of species, the complexity of food webs, and the rate of nutrient cycling all affect how stable an ecosystem is. More species means a more complex food web and a faster rate of nutrient cycling, which means the ecosystem is more stable. The more stable an ecosystem is, the more productive it will be. The stability of an ecosystem is low if it is easy to damage. Man-made or artificial ecosystems, for example, are not very stable. But if the ecosystem can bounce back quickly, that means it is strong. High resilience could be caused by humans or by fast-growing plants and animals that move in from other places.

Ans: (a) low moisture content

Explanation: Microorganisms break down the complex compounds in the dead protoplasm of producers and consumers. Some of the breakdown products are taken in by the producers and consumers, and simple substances are released. Logs that have fallen in nature take a long time to break down because they don't have much water in them. Logs that have been cut down have a lot of cellulose. The air around the fallen logs is full of oxygen.

Ans: Sparrow

Explanation: A sparrow is an animal that can live on more than one trophic level at the same time. When a sparrow eats seeds, fruits, and peas, it is a primary consumer. When it eats bugs and worms, it is a secondary consumer.

Ans: (b) 10 kg

Explanation: In a grassland ecosystem, the relationship between biomass is like a triangle, with producers at the top with the most biomass.

The first-level consumers, or herbivores, eat the producers on the second level. On the third level are the carnivores that eat the herbivores. As we go up the food chain, the amount of biomass keeps going down.

If we start with 1000 kg of producers, 100kg will go to herbivores and 10 kg to carnivores.

Ans: (b) Carnivorous secondary consumer

Explanation: Carnivorous and a secondary consumer, the whale feeds on other animals that are considered primary consumers (eating zooplankton and small fishes). It is located at the third rung of the ecosystem's trophic hierarchy.

Ans: (b) Deer & Bees

Explanation: A food chain is a group of plants and animals that are linked by the fact that one eats the other for food. A food chain has several different trophic levels. In this case, plants are the main source of food. They are at the top of the food chain. They eat plants, which is why they are referred to as "primary consumers”. These are plants-eaters. Cow, bee, deer, and earthworm are all examples. Animals that eat animals that eat other animals are called secondary consumers. These things eat meat. Tiger, crow, frog, and wild boar are some examples. Animals that eat animals that eat other animals are called "tertiary consumers." Snake and tiger are two examples.