Here are some critical Chapter 13 Our Environment Problems for Class 10 Science. These inquiries are intended to aid students in studying for and performing well on the CBSE Class 10 Science Examination 2023–24. Students can clear up their concerns and be ready for the exams by practising different types of questions. By answering these questions, you'll increase your confidence while also sharpening your problem-solving abilities
In Chapter 13, "Our Environment," of Class 10 Science, students embark on a journey to understand the delicate balance of ecosystems. This chapter delves into the components that constitute an ecosystem, shedding light on the intricate interplay of living and non-living entities. Moreover, it scrutinizes various human activities that impact the environment, fostering awareness about our role in safeguarding the delicate ecological equilibrium for a sustainable future.
Grasshoppers depend upon grass for their food, they cannot make their own food. Hence they are primary consumers as they depend upon producers.Now if the grasshoppers are eaten by frogs they become the secondary producers.
The decomposers in an ecosystem convert organic matter present in dead remains into inorganic elements. These elements are then released into the environment to enter into biogeochemical cycles.
Vegetarians obtain food directly from plants, while non-vegetarians get food from animals which feed on plants. As a result animals which are herbivores get 10% of energy from plants, suppose 100 J according to the 10% rule. When non-vegetarians feed upon these animals they get only 10 J which is 10% of 100 J. But vegetarians which feed directly on plants get 100 J hence vegetarians are at an advantageous position and get more energy than non-vegetarians.
(a) An energy pyramid is a graphical representation of the flow of energy from the producers through the various consumers. It shows the amount of energy available and the loss of useful energy at each step of the food chain in an ecosystem. As the energy gets transferred from lower trophic level to the higher one, there is a loss of large amounts of energy due to metabolism and heat. As a result very little energy (i.e., 10%) gets transferred to the next level. So the trophic level at the base has maximum energy and that at the top has the least amount of energy. Hence the energy pyramid is broader at the base and narrower at the top.
(b) The average percentage of energy lost when plants are eaten by primary consumers is 90%.
(a) (i) Plants capture only about 1% of the solar energy that falls on them and use it for photosynthesis.
(ii) On average, only about 10 percent of energy stored as biomass in a trophic level is passed from one level to the next. This is known as “10 percent rule” and it limits the number of trophic levels an ecosystem can support.
(b) The various steps in a food chain or ecological pyramid, at which the transfer of food (or energy) takes place from one organism to another organism is known as trophic levels. Based on the source of their nutrition or food, organisms occupy a specific place in the food chain. Organisms in food webs are grouped into categories called trophic levels, these levels are divided into producers (first trophic level), consumers, and decomposers (last trophic level). There is only 10% flow of energy from one trophic level to the next higher level. The loss of energy at each step is so great that very little usable remains after four or five trophic levels. Hence only 4 to 5 trophic levels are present in each food chain.
Oswal.io offers a thorough set of questions for learning the topic in a better way if you're looking to further practise and improve your grasp of the concepts covered in the chapter.
Ans: The pesticides are not biodegradable, they get accumulated progressively at each trophic level. As human beings occupy the topmost level in the food chain, their concentration becomes maximum in our bodies.
Ans: By using biological methods for controlling insects in fields and by washing fruits and vegetables before eating could help to reduce our intake of pesticides through food to some extent.
Ans: An ecosystem is defined as a structural and functional unit of the biosphere. It comprises living organisms and their nonliving environment that interact by means of food chains and biogeo-chemical cycles resulting in energy-flow, biotic diversity and material cycling to form stable self-supporting systems.
Ans: Lake is an ecosystem where living organisms grow, reproduce and interact among each other as well as with abiotic components and carry out other activities in nature by themselves without any human interference, therefore it is referred to as a natural ecosystem.
Ans: Two biotic components of a biosphere are:
(i) Producers – Include organisms which can produce their food using simple inorganic compounds, e.g., all green plants, blue green algae (cyanobacteria).
(ii) Consumers – Include organisms which are unable to synthesise their food, therefore, utilise materials and energy stored by the producers or eat other organisms, e.g., all the animals.