Class 12 Anthropology Chapter 7 Ecology or Environmental Studies Solutions with complete textual questions and answers, important additional exam-oriented questions and answers, and easy-to-understand solutions for effective exam preparation.
Class 12 Anthropology Chapter 7 Ecology or Environmental Studies Solutions
Textual Questions & Solutions
A. Short Questions & Answers:
- Who first coined the term Ecology?
Ans: The term “ecology” was coined by the German biologist Ernst Haeckel in 1866.
- What is the etymological meaning of the term Ecology?
Ans: The term “ecology” is derived from the Greek words oikos, meaning “home” or “household,” and logos, meaning “study” or “knowledge.” Thus, ecology literally means the study of the household of nature.
- What is environment?
Ans: Environment refers to the totality of external conditions and influences, both biotic and abiotic, that surround and affect living organisms, including their growth, development, behaviour, and survival.
- Define ecology.
Ans: Ecology is the scientific study of the relationships of living organisms with one another and with their biotic and abiotic environment. Ernst Haeckel defined ecology as the study of the relationships of organisms with both their organic and inorganic surroundings.
- What are the two components of water?
Ans: Water is composed of hydrogen and oxygen. A water molecule contains two hydrogen atoms and one oxygen atom (H₂O).
- What do mean by ecological balance?
Ans: Ecological balance refers to a state of dynamic stability in an ecosystem in which organisms interact with one another and with their environment, while natural processes such as energy flow and nutrient cycling continue to function effectively.
- What is physical environment?
Ans: The physical environment consists of the non-living surroundings, such as air, water, land, sunlight, temperature, rainfall, atmospheric pressure, humidity, and wind.
- What is social environment?
Ans: The social environment refers to the social and cultural surroundings in which people live and interact. It includes family, community, social groups, institutions, customs, traditions, values, and other forms of social organization.
- What are the basic elements of environment?
Ans: The basic elements of the environment may be broadly classified into the biotic components, which include living organisms, and the abiotic components, which include non-living factors such as air, water, soil, light, and temperature.
- What do you mean by water cycle?
Ans: The water cycle is the continuous circulation of water between the atmosphere, land, and water bodies. Water evaporates from oceans, lakes, rivers, and other water bodies due to solar energy, condenses to form clouds, and returns to the Earth’s surface as precipitation. The water then flows into water bodies or infiltrates the soil, and the cycle continues.
- What is phytoplankton?
Ans: Phytoplankton are microscopic, photosynthetic organisms that float or drift in aquatic environments. They are mainly composed of microscopic algae and other photosynthetic organisms and act as important primary producers in aquatic ecosystems.
- What is smog?
Ans: Smog is a form of air pollution in which pollutants accumulate in the atmosphere and reduce visibility and air quality. Photochemical smog forms when nitrogen oxides and volatile organic compounds react in the presence of sunlight, producing secondary pollutants such as ground-level ozone. Smog is particularly common in heavily industrialized and densely populated areas.
- What are the major greenhouse gases?
Ans: The major greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, ozone, and fluorinated gases such as chlorofluorocarbons (CFCs) and other halogenated compounds.
- What do you mean by Green House Effect?
Ans: The greenhouse effect is the natural process by which certain gases in the Earth’s atmosphere absorb and re-radiate outgoing infrared radiation, thereby keeping the Earth’s surface and lower atmosphere warmer than they would otherwise be. Greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, ozone, and certain human-made gases. The natural greenhouse effect is essential for life, although an enhanced greenhouse effect caused mainly by human activities contributes to global warming.
- What is Global Warming?
Ans: Global warming refers to the long-term increase in the average temperature of the Earth’s surface and lower atmosphere, mainly due to the increasing concentration of human-produced greenhouse gases. The major sources include the burning of fossil fuels, deforestation, and certain industrial and agricultural activities.
- What is acid rain?
Ans: Acid rain is precipitation that is more acidic than normal because atmospheric pollutants, particularly sulphur dioxide (SO₂) and nitrogen oxides (NOₓ), react with water and other substances in the atmosphere to form sulphuric and nitric acids. Acid deposition can adversely affect aquatic ecosystems, vegetation, soil, and buildings.
- What do you mean by food chain and food web?
Ans: A food chain is a sequence of organisms through which energy and nutrients are transferred as one organism is eaten by another. Food chains may begin with producers, such as green plants, or with dead organic matter in detritus-based food chains.
A food web is a network of interconnected food chains within an ecosystem. It shows the complex feeding relationships among organisms at different trophic levels.
B. Essay Type Questions:
- Define ecosystem. What are the different components of an ecosystem? Describe with examples.
Ans: An ecosystem is a functional unit of nature in which living organisms interact with one another and with the non-living components of their environment. An ecosystem may be a pond, forest, grassland, river, or even a small garden. Energy flows through the ecosystem, while nutrients are continuously recycled.
An ecosystem has two major components:
(1) Abiotic Components (Non-living): Abiotic components are the non-living physical and chemical factors of an ecosystem. They include:
(a) Climatic Factors:These include temperature, rainfall, sunlight, humidity, wind, and atmospheric conditions.
(b) Edaphic Factors: These are soil-related factors such as soil type, soil moisture, pH, minerals, and soil structure. Topography may also influence the physical conditions of an ecosystem.
(2) Biotic Components (Living):
The biotic components consist of all living organisms present in an ecosystem, including plants, animals, fungi, bacteria, and other microorganisms. They are generally grouped into three categories:
(i) Producers or Autotrophs: Producers are organisms that manufacture their own food, mainly through photosynthesis. Green plants, algae, and many phytoplankton are examples. During photosynthesis, they use light energy to convert carbon dioxide and water into organic compounds such as carbohydrates.
(ii) Consumers or Heterotrophs: Consumers cannot produce their own food and obtain energy by feeding on other organisms. They include herbivores, carnivores, omnivores, and other animals.
(iii) Decomposers: Decomposers, particularly bacteria and fungi, break down dead organic matter into simpler substances. They play an essential role in nutrient cycling by returning nutrients to the environment for reuse by producers.
Thus, the interaction between abiotic and biotic components makes an ecosystem a functioning ecological system.
- What is ecology? Discuss its subject matter.
Ans: Ecology is the scientific study of the relationships of living organisms with one another and with their environment. Ernst Haeckel used the term “ecology” in the nineteenth century to refer to the study of the relationships of organisms with their surroundings.
Subject Matter of Ecology:
Ecology studies organisms at different levels of biological organization, from individual organisms to the entire biosphere. Its major areas of study include:
(i) Organismal Ecology: It studies how individual organisms respond to and interact with their biotic and abiotic environment. It includes aspects such as behaviour, physiology, morphology, and adaptation.
(ii) Population Ecology: It studies populations of organisms, including their size, density, distribution, growth, age structure, and changes over time, as well as the factors affecting population dynamics.
(iii) Community Ecology: It studies interactions among populations of different species living together in a particular area. These interactions include competition, predation, parasitism, and mutualism.
(iv) Ecosystem Ecology: It studies the interactions between living organisms and the abiotic environment within an ecosystem, including energy flow and nutrient cycling.
(v) Landscape Ecology: It studies the relationships among different ecosystems and the movement of organisms, energy, and materials across landscapes. It also examines the effects of human activities on landscape structure and ecological processes.
(vi) Global Ecology: It studies ecological processes and interactions at the global level, including relationships among ecosystems, the atmosphere, oceans, and land systems.
Modern ecology may also draw upon molecular and genetic approaches to understand ecological processes at smaller biological scales.
- What is the importance of studying ecology?
Ans: The study of ecology is important because it helps us understand the relationships between living organisms and their environment. It explains how organisms interact with one another and with non-living factors such as air, water, soil, light, and temperature.
Ecological knowledge is essential for understanding the functioning of ecosystems, conserving biodiversity, managing natural resources, and protecting wildlife. It also helps us understand environmental problems such as pollution, deforestation, habitat destruction, climate change, and loss of biodiversity.
The study of ecology provides a scientific basis for environmental conservation and for developing sustainable ways of using natural resources. It therefore contributes to the protection of ecosystems and the well-being of present and future generations.
- Discuss ecological balance versus matter.
Ans: Ecological balance refers to the dynamic stability of relationships among organisms and between organisms and their environment. Matter, on the other hand, refers to the physical substances that make up living organisms and their surroundings, including air, water, soil, minerals, and organic materials.
Matter is essential for life and is continuously circulated through ecosystems. For example, water moves through the water cycle, while elements such as carbon, nitrogen, and phosphorus circulate through biogeochemical cycles.
Ecological balance depends partly on the proper cycling and availability of matter. Plants obtain water and minerals from the environment and carbon dioxide from the atmosphere; animals obtain nutrients by consuming plants or other animals; and decomposers return nutrients to the environment when they break down dead organic matter.
Human activities such as pollution, deforestation, excessive resource extraction, and improper waste disposal can disrupt natural cycles and ecological relationships. Therefore, maintaining healthy ecosystems requires the responsible use and conservation of natural resources.
- What is ecological balance? Discuss man as a main factor of disturbing ecological balance.
Ans: Ecological balance refers to the dynamic stability maintained through interactions among organisms and between organisms and their environment. It involves processes such as energy flow, nutrient cycling, population regulation, and interactions among different species.
Human beings are one of the major factors capable of disturbing ecological balance because human activities can substantially alter natural ecosystems. Important human activities that may cause ecological disturbances include:
(i) Deforestation: Large-scale removal of forests destroys habitats, reduces biodiversity, and may increase soil erosion.
(ii) Pollution: Air, water, and soil pollution can adversely affect organisms and disrupt ecological processes.
(iii) Overexploitation of Natural Resources: Excessive hunting, fishing, logging, mining, and extraction of other resources can reduce populations and damage ecosystems.
(iv) Industrialization and Urbanization: Expansion of industries, towns, roads, and other infrastructure can result in habitat loss and fragmentation.
(v) Agricultural Activities: Intensive agriculture, excessive use of fertilizers and pesticides, and conversion of natural habitats can affect soil, water, and biodiversity.
(vi) Greenhouse Gas Emissions: The burning of fossil fuels and other human activities increase greenhouse gas concentrations and contribute to global climate change.
Therefore, human activities can significantly disturb ecological relationships. Sustainable resource use, pollution control, habitat conservation, restoration of degraded ecosystems, and responsible environmental management can help reduce these disturbances.
- Discuss the relation between ecology and environment.
Ans: Ecology and environment are closely related concepts. The environment refers to the surrounding conditions, resources, and influences that affect living organisms. It includes both biotic components, such as plants, animals, and microorganisms, and abiotic components, such as air, water, soil, temperature, and sunlight.
Ecology is the scientific study of the relationships between organisms and their environment. It examines how organisms interact with one another and how they respond to and influence the physical and chemical conditions around them.
Thus, the environment provides the conditions and resources necessary for life, while ecology studies the relationships and interactions that occur within that environment. For example, in a forest ecosystem, the soil, water, sunlight, and temperature form part of the environment, while the relationships among trees, animals, microorganisms, and these physical factors are studied by ecology.
The study of ecology therefore helps us understand how environmental changes affect living organisms and how human activities can alter ecosystems. This knowledge is important for conserving natural resources, maintaining biodiversity, and promoting sustainable environmental management.
Additional Questions & Solutions
Multiple Choice Questions (MCQ)
- Who coined the term ‘Ecology’?
(i) Charles Darwin.
(ii) Ernst Haeckel.
(iii) E.P. Odum.
(iv) R. Misra.
Ans: (ii) Ernst Haeckel.
- What is the etymological meaning of the word ‘Ecology’?
(i) Study of interactions.
(ii) Study of organisms.
(iii) Study of home.
(iv) Study of nature.
Ans: (iii) Study of home.
- Which Act defines environment legally in India?
(i) Environment Protection Act, 1986.
(ii) Air Pollution Act, 1981.
(iii) Water Act, 1974.
(iv) Environment Act, 1992.
Ans: (i) Environment Protection Act, 1986.
- Which layer of atmosphere contains the ozone layer?
(i) Mesosphere.
(ii) Thermosphere.
(iii) Stratosphere.
(iv) Troposphere.
Ans: (iii) Stratosphere.
- Which gas is most abundant in the atmosphere?
(i) Argon.
(ii) Nitrogen.
(iii) Oxygen.
(iv) Carbon dioxide.
Ans: (ii) Nitrogen.
- Which is a non-renewable natural resource?
(i) Solar energy.
(ii) Petroleum.
(iii) Water.
(iv) Wind.
Ans: (ii) Petroleum.
- Greenhouse gases do NOT include:
(i) CH₄
(ii) CFC
(iii) N₂
(iv) CO₂
Ans: (iii) N₂.
- The functional unit of ecology is called:
(i) Habitat.
(ii) Ecosystem.
(iii) Biosphere.
(iv) Biome.
Ans: (ii) Ecosystem.
- Which of the following is a primary consumer?
(i) Eagle.
(ii) Cow.
(iii) Lion.
(iv) Snake.
Ans: (ii) Cow.
- Photosynthesis takes place in:
(i) Carnivores.
(ii) Autotrophs.
(iii) Consumers.
(iv) Decomposers.
Ans: (ii) Autotrophs.
- The main source of energy for all ecosystems is:
(i) Soil.
(ii) Sun.
(iii) Moon.
(iv) Wind.
Ans: (ii) Sun.
- The process of eating and being eaten is known as:
(i) Adaptation.
(ii) Food chain.
(iii) Ecology.
(iv) Food web.
Ans: (ii) Food chain.
- Soil that originates from organic remains is called:
(i) Inorganic soil.
(ii) Organic soil.
(iii) Artificial soil.
(iv) Mineral soil.
Ans: (ii) Organic soil.
- Water makes up how much of the Earth’s surface?
(i) 75%
(ii) 60%
(iii) 80%
(iv) 70%
Ans: (iv) 70%.
- Acid rain is caused by:
(i) O₃ and CO.
(ii) SO₂ and CO.
(iii) SO₂ and NO₂.
(iv) CO₂ and CH₄.
Ans: (iii) SO₂ and NO₂.
- Which of the following is an example of a food web?
(i) Grass → Grasshopper → Frog → Snake
(ii) Grass → Cow → Tiger
(iii) Several interconnected food chains
(iv) Sun → Plant → Herbivore
Ans: (iii) Several interconnected food chains
- Which of the following organisms is a producer in an ecosystem?
(i) Lion
(ii) Green plant
(iii) Snake
(iv) Fungi
Ans: (ii) Green plant
- Which of the following is an abiotic component of an ecosystem?
(i) Plants
(ii) Animals
(iii) Microorganisms
(iv) Water
Ans: (iv) Water
- Which of the following gases is mainly responsible for the enhanced greenhouse effect?
(i) Carbon dioxide
(ii) Nitrogen
(iii) Oxygen
(iv) Hydrogen
Ans: (i) Carbon dioxide
- Which of the following is a major cause of global warming?
(i) Increase in greenhouse gases
(ii) Increase in soil fertility
(iii) Decrease in food chains
(iv) Increase in rainfall
Ans: (i) Increase in greenhouse gases.
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