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Ecological Concept: AHSEC Class 11 Environmental Education
Get summay, questions, answers, solutions, notes, extras, PDF, competency-based questions of chapter- 2/unit I, Ecological Concept: AHSEC Class 11 Environmental Education, which is part of the present syllabus. These solutions, however, should only be treated as references and can be modified/changed.
Summary
Ecology is the study of how living things interact with each other and their natural home, or environment. It looks at the connections between all parts of nature, including plants, animals, and micro-organisms. There are many connections between the different parts of nature. For example, a plant takes water and nutrients from the soil to grow. An animal like a deer might eat the plant. When the deer dies, tiny organisms like bacteria and fungi break down its body. This process returns nutrients like nitrogen and carbon back to the soil, which helps new plants grow.
To understand ecology, we can look at different levels of organization. The smallest level is an organism, which is any single living being. A group of similar organisms that can breed together is called a species. A group of the same species living in one area is a population. Many different populations living and interacting in the same area form a community. When you include the community and the non-living things around it, like soil, water, and sunlight, you have an ecosystem.
Ecosystems can be natural or artificial. Natural ecosystems, like forests or oceans, exist without human help. Artificial ecosystems, such as farms or man-made ponds, are created by people and need human care to stay in balance. Every ecosystem has living parts, called biotic components, and non-living parts, called abiotic components. The living parts are grouped by how they get food. Producers, like plants, make their own food using sunlight. Consumers get their food by eating other living things. Animals that eat plants are herbivores, while those that eat other animals are carnivores. Decomposers break down dead plants and animals.
Energy moves through an ecosystem in a food chain, which shows who eats whom. For instance, grass is eaten by a grasshopper, which is then eaten by a bird. Many food chains connected together form a food web. A food web is like a spider’s web because it shows many different paths for energy, as most animals eat more than one type of food. Each step in a food chain is a trophic level. Plants are the first level, herbivores are the second, and so on. We can draw these levels as an ecological pyramid, which shows how the amount of energy decreases at each higher level.
Textual/Exercise
1. Define the term ecology.
Answer: The word ‘ecology’ is derived from the Greek words oikos (means- home) and logos (means – study). So ecology deals with the study of organisms in their natural homes interacting with their surroundings or environment. In other words, ecology is the study of the interconnections and interdependence of plants, animals and their environment.
2. What do you mean by ecosystem?
Answer: An ecosystem is a community of organisms involved in a dynamic network of biological, chemical and physical interactions between themselves and with the non-living components. Such interactions sustain the system and allow it to respond in changing conditions. Thus, an ecosystem includes the biological components, the non-living components (physical environment) and their interactions.
3. Classify the ecosystems.
Answer: Ecosystem is of two major types:
a) Natural ecosystem
b) Artificial or man-made ecosystem
Natural ecosystem is again divided into:
a) Terrestrial ecosystem (for example – forest ecosystem, grassland ecosystem, desert ecosystem) and
b) Aquatic ecosystem, which can be fresh water ecosystem and marine ecosystem.
Man-made ecosystems are created by man. For example – cropland ecosystem, fisheries etc.
4. What are lotic and lentic ecosystems ? Give examples.
Answer: A fresh water ecosystem may be lotic, which is a free flowing type, for example, rivers. A lentic ecosystem is a standing type, for example, ponds and lakes.
5. What are producers, consumers and decomposers ?
Answer: Producers are known as autotrophs. They can produce their food themselves by making use of carbon dioxide present in air and water in the presence of sunlight by involving chlorophyll, through the process of photosynthesis. Some micro-organisms can also produce organic matter through oxidation of certain chemicals in the absence of sunlight.
Consumers are known as heterotrophs. They cannot produce their food by themselves and get their organic food from the producers. The animals that consume the producers either directly or indirectly are called macro consumers.
Decomposers are micro consumers. They are certain living organisms that derive their nutrients by decomposing or breaking down dead plants and biotic compounds in the environment. Examples include bacteria and fungus.
6. Write briefly on structure and functions of an ecosystem.
Answer: The structure of an ecosystem is constituted by the composition and organization of its biotic and abiotic components. The biotic structure is formed by the plants, animals, and micro-organisms present in the ecosystem. The abiotic structure is constituted by the physical and chemical components. This includes physical factors like sunlight, temperature, and rainfall, as well as soil factors. Chemical components include major nutrients like carbon and nitrogen, and compounds like carbohydrates and proteins present in soil and water.
The function of an ecosystem is performed in a systematic way under natural conditions. It receives energy from the sun and passes it to different components at different levels. The function of an ecosystem can only be considered as a whole, as every part has a functional effect on another. The major functional characteristics of an ecosystem may be described in terms of food chain, food webs and trophic levels, energy flow, and nutrient cycles.
7. What are food chain and food web ?
Answer: In an ecosystem, the sequential chain of eating and being eaten is called a food chain.
A food web is a network of food chains where different types of organisms are connected at different trophic levels. A number of food chains interwoven with one another give rise to interlocking patterns, which are called food webs. This provides a number of options for eating and being eaten at each trophic level.
8. What is trophic level.
Answer: Every organism in an ecosystem can be assigned a feeding level, referred to as the trophic level. The living organisms which derive energy from the same source are said to belong to the same trophic level. For example, green plants are in the first trophic level (producers), herbivores are in the second trophic level (primary consumers), and carnivores are in the third (secondary consumers), and so on.
9. What do you mean by ecological pyramids? Name the different types of ecological pyramids.
Answer: The graphical representation of the trophic structure and functions of an ecosystem with producers at the base and successive trophic levels of consumers forming the higher layers (apex) is known as ecological pyramids.
The three basic types of ecological pyramids are:
- The pyramid of numbers: Here the numbers of individual organisms are depicted.
- The pyramid of biomass: This is based on the total dry weight or other measures of the total amount of living matter.
- The pyramid of energy: In this pyramid, the energy assimilated and/or productivity at successive trophic levels is shown.
10. Mention the main characteristics of food chain and food web.
Answer: The main characteristics of a food chain are that it is a sequential chain of eating and being eaten, and it is always unidirectional. There are two types: the grazing food chain, which starts from green plants, and the detritus food chain, which starts with detritus produced by green plants.
The main characteristics of a food web are that it is a network of several interconnected and interwoven food chains. It shows the feeding relationships in an ecosystem where different organisms are connected at different trophic levels, providing a number of options for eating and being eaten.
Extra/additional questions and answers
1. From which Greek words is the term ‘ecology’ derived?
Answer: The term ‘ecology’ is derived from the Greek words oikos and logos. ‘Oikos’ means home, and the Greek word ‘logos’ means study.
2. What is an organism? Give an example.
Answer: An organism is any form of life. A wide variety of organisms are present on earth, with examples ranging from the single-celled amoeba and microscopic blue-green algae to huge sharks and massive banyan trees.
3. What is a species?
Answer: A species is a group of organisms that resemble one another in appearance, behaviour, chemistry, and genetic structure. Organisms of the same species can breed with one another and produce fertile offspring under natural conditions.
4. What is a population? Give an example.
Answer: A population is a group of individuals of the same species that occupy a given area at a given time. For example, the population of Rhinoceros unicornis in the Kaziranga National Park in Assam is a population.
5. What is a community?
Answer: A community is made up of populations of various species that occupy a particular area and interact with each other. It comprises several different species that interact within the same environment.
6. What are the two major types of ecosystems?
Answer: The two major types of ecosystems are the natural ecosystem and the artificial or man-made ecosystem.
7. What is a terrestrial ecosystem? Give an example.
Answer: A terrestrial ecosystem is a type of natural ecosystem that is found on land. Examples of terrestrial ecosystems include a forest ecosystem, a grassland ecosystem, and a desert ecosystem.
8. What are the two types of freshwater ecosystems?
Answer: The two types of freshwater ecosystems are lotic ecosystems, which are free-flowing like rivers, and lentic ecosystems, which are standing types like ponds and lakes.
9. Give an example of a man-made ecosystem.
Answer: An example of a man-made ecosystem is a cropland ecosystem. Other examples of artificial ecosystems include fisheries, orchards, large or small gardens, and farms.
10. What are autotrophs also known as?
Answer: Autotrophs are also known as producers. They are called this because they can produce their own food using elements from their environment, such as sunlight, air, and water.
11. What are heterotrophs also known as?
Answer: Heterotrophs are also known as consumers. They are called this because they cannot produce their own food and must get their organic food by consuming producers or other consumers.
12. What are herbivores? Give an example.
Answer: Herbivores are animals that directly consume producers, which are plants. They are also called primary consumers. Examples of herbivores include cows, deer, and goats.
13. What are secondary consumers?
Answer: Secondary consumers are carnivores that feed on herbivores. They occupy the third trophic level in a food chain, obtaining their energy by eating primary consumers.
14. What are tertiary consumers? Give an example.
Answer: Tertiary consumers are carnivores that feed on other carnivores. An example of a tertiary consumer is a snake that eats a frog, or a big fish that eats a smaller fish.
15. What are omnivores? Give an example.
Answer: Omnivores are organisms that feed on both plants and animals to get their energy and nutrients. Examples of omnivores include humans, foxes, and rats.
16. What are detrivores? Give an example.
Answer: Detrivores are organisms that generally feed on dead animals, partially decomposed matter, and the wastes of other living organisms. Examples include beetles, ants, and earthworms.
17. What are micro consumers also known as?
Answer: Micro consumers are also known as decomposers. These are organisms like bacteria and fungi that get their nutrients by decomposing or breaking down dead plants and other biotic compounds.
18. What is a food chain?
Answer: A food chain describes the sequential process of eating and being eaten within an ecosystem. It shows how energy is transferred from one living organism to another in a linear sequence.
19. What is a grazing food chain?
Answer: A grazing food chain is a type of food chain that starts with green plants, or autotrophs, as the first trophic level. In this chain, herbivores eat the plants, and then predators eat the herbivores.
20. What is a detritus food chain?
Answer: A detritus food chain is a type of food chain that starts with detritus, which is the debris produced by dead green plants and other decaying organic matter.
21. What is a food web?
Answer: A food web is a network of several interconnected food chains. It represents the complex feeding relationships within an ecosystem, showing how different organisms are connected at various trophic levels.
22. What are ecological pyramids?
Answer: Ecological pyramids are graphical representations of the trophic structure and functions of an ecosystem. They are drawn with producers at the base and successive trophic levels of consumers forming the higher layers.
23. Explain the intricate connections in nature with an example.
Answer: There are intricate connections between the various components of nature. For instance, green plants take nutrients and water from the soil. Their leaves, fruits, and other parts may then be eaten by an animal like a bird or a deer. When these animals die, a part of their dead remains is eaten by bacteria and fungi. The remainder is broken down into smaller elements like nitrogen, carbon, and sulphur, which go back to the soil. This process connects them all in a continuous cycle.
24. Describe the hierarchy of organization in ecology.
Answer: The best way to understand ecology is to look at the levels of organization it focuses on. These levels, in a hierarchy, are organisms, species, population, communities, and ecosystems.
An organism is any form of life, ranging from a single-celled amoeba to a huge shark, or from microscopic blue-green algae to a massive banyan tree.
A species is a group of organisms that look alike in appearance, behaviour, chemistry, and genetic structure. Organisms of the same species can breed with each other and produce fertile offspring.
A population is a group of individuals of the same species that live in a particular area at a given time. For instance, all the Rhinoceros unicornis in Kaziranga National Park form a population.
A community is made up of populations of various species living in a particular area and interacting with each other. The community of Kaziranga National Park includes the rhino population, elephant population, grass population, and all other life forms there.
An ecosystem is a community of organisms interacting with each other and with their non-living environment, which includes physical components like soil, water, and rocks. These interactions create a functional system.
25. How does a species differ from a population? Give examples.
Answer: A species is a group of organisms that resemble one another in appearance, behaviour, chemistry, and genetic structure. Organisms of the same species can breed with one another to produce fertile offspring. For example, all human beings belong to the species Homo sapiens.
A population, on the other hand, is a group of individuals of the same species that occupy a given area at a given time. For example, all the Rhinoceros unicornis in the Kaziranga National Park in Assam make up a population. Thus, a species is a category of organism, while a population is a specific group of that species in one place.
26. Explain the different types of macro consumers found in an ecosystem with suitable examples for each category.
Answer: Macro consumers are the animals that consume producers either directly or indirectly. They can be divided into four main types based on what they eat.
(i) Herbivores: These are animals that directly consume producers (plants). They are also known as primary consumers. Examples include cows, deer, and goats.
(ii) Carnivores: These are animals that feed on other consumers. If they feed on herbivores, they are called secondary consumers, like a frog. If they feed on other carnivores, they are known as tertiary consumers, such as a snake or a big fish.
(iii) Omnivores: These animals feed on both plants and other animals. Examples include man, fox, and rat.
(iv) Detrivores: These organisms generally feed on dead animals, partially decomposed matter, and the wastes of other living organisms. Examples are beetles, ants, and earthworms.
27. What are micro consumers? What is their role in an ecosystem?
Answer: Micro consumers are certain living organisms that derive their nutrients by decomposing or breaking down dead plants and other biotic compounds in the environment. They are also called decomposers. Their role is essential for the ecosystem as they break down complex organic matter into simpler substances, returning nutrients to the soil and water, which can then be used by producers. Examples of micro consumers include bacteria and fungus.
28. Describe the three basic types of ecological pyramids and what each represents.
Answer: There are three basic types of ecological pyramids, each representing a different aspect of the ecosystem’s trophic structure.
The pyramid of numbers shows the total number of individual organisms at each trophic level.
The pyramid of biomass is based on the total dry weight or other measures of the total amount of living matter at each successive trophic level.
The pyramid of energy shows the amount of energy that is assimilated or the productivity at each successive trophic level.
These ecological pyramids are useful for comparing the biomass and energy flow between different trophic levels. Such comparisons can help in identifying which ecosystems and communities are more efficient in terms of energy transfer.
29. Distinguish between ecology and ecosystem.
Answer: Ecology is the study of organisms in their natural homes interacting with their surroundings or environment. It is the study of the interconnections and interdependence of plants, animals, and their environment. The essence of ecology lies in the study of the togetherness of everything, including plants, animals, micro-organisms, and their environment.
An ecosystem, on the other hand, is a community of organisms involved in a dynamic network of biological, chemical, and physical interactions between themselves and with non-living components. An ecosystem includes the biological components, the non-living components, and their interactions. According to Odum, the ecosystem is the main active unit of ecology.
30. Distinguish between a population and a community.
Answer: A population is a group of individuals of the same species occupying a given area at a given time. For example, the Rhinoceros unicornis in the Kaziranga National Park, Assam, make a population.
A community, on the other hand, is made up of populations of various species occupying a particular area and interacting with each other. For example, the community of the Kaziranga National Park refers to the rhino population, the elephant population, the cattle population, the grass population, and populations of all kinds of life forms present there. Thus, a community comprises several species interacting with each other.
31. Distinguish between a community and an ecosystem.
Answer: A community is made up of populations of various species occupying a particular area and interacting with each other. It comprises several species interacting with each other.
An ecosystem includes the community of organisms but also involves the non-living components. An ecosystem is a community of organisms involved in a dynamic network of interactions between themselves and with the non-living components like soil, rocks, water, and solar energy.
32. Distinguish between natural and artificial ecosystems.
Answer: A natural ecosystem is an ecosystem that is found in nature, where there is no interaction with humans. It is a system where everything is in balance, and if one component is removed, the system will fall apart.
An artificial ecosystem, on the other hand, is constructed in some fashion by humans. For example, a pond is built, plants are physically planted, and varieties of fish species are released into it. To keep the constructed wetland in balance, human intervention is needed to maintain the ecosystem. Other artificial ecosystems are orchards, large or small gardens, and farms.
33. Distinguish between terrestrial and aquatic ecosystems.
Answer: Terrestrial and aquatic ecosystems are the two major categories of natural ecosystems, defined by their habitat. Terrestrial ecosystems are found on land, with examples including forest ecosystems, grassland ecosystems, and desert ecosystems. Deserts, forests, meadows, prairies, and jungles are all terrestrial ecosystems. Aquatic ecosystems, on the other hand, include all marine and freshwater systems.
34. Distinguish between biotic and abiotic components of an ecosystem.
Answer: The biotic components of an ecosystem are the living parts, which include the plants, animals, and micro-organisms present in the ecosystem.
The abiotic components, on the other hand, are the non-living physical and chemical components. The abiotic structure includes physical factors like sunlight, temperature, and rainfall, as well as edaphic (soil) factors. It also includes chemical components like major nutrients such as carbon and nitrogen, and compounds like carbohydrates and proteins present in soil and water.
35. Distinguish between autotrophs and heterotrophs.
Answer: Autotrophs are known as producers and can produce their food themselves. They make use of carbon dioxide present in air and water in the presence of sunlight through the process of photosynthesis.
Heterotrophs, on the other hand, are organisms that cannot produce their food by themselves. They get their organic food from the producers and are therefore called consumers.
36. Distinguish between producers and consumers.
Answer: Producers are autotrophs that can produce their own food by making use of carbon dioxide, water, and sunlight through photosynthesis. Consumers are heterotrophs that cannot produce their own food and get their organic food from the producers.
37. Distinguish between herbivores and carnivores.
Answer: Herbivores are animals that directly consume producers. They are also called primary consumers. Examples include cows, deer, and goats.
Carnivores, on the other hand, feed on other consumers. If they feed on herbivores, they are called secondary consumers, and if they feed on other carnivores, they are known as tertiary consumers. Examples include frogs, snakes, and big fish.
38. Distinguish between primary consumers and secondary consumers.
Answer: Primary consumers are herbivores, which are animals that directly consume producers. Secondary consumers are carnivores that feed on other consumers, specifically on herbivores.
39. Distinguish between macro consumers and micro consumers.
Answer: Macro consumers are the animals that consume producers either directly or indirectly. They can be divided into types like herbivores, carnivores, omnivores, and detrivores.
Micro consumers, also known as decomposers, are certain living organisms like bacteria and fungus that derive their nutrients by decomposing or breaking down dead plants and biotic compounds in the environment.
40. Distinguish between consumers and decomposers.
Answer: Consumers are organisms that get their organic food from producers. Macro consumers are animals that consume producers either directly or indirectly.
Decomposers, also called micro consumers, are organisms that derive their nutrients by decomposing or breaking down dead plants and biotic compounds in the environment. Examples of decomposers are bacteria and fungus.
41. Distinguish between a food chain and a food web.
Answer: A food chain is the sequential chain of eating and being eaten in an ecosystem. It is always unidirectional. For example, Grasses – cattle – tiger.
A food web, on the other hand, is a network of several food chains interwoven with one another. These interlocking patterns show that different types of organisms are connected at different trophic levels, providing a number of options for eating and being eaten at each level.
42. Distinguish between a grazing food chain and a detritus food chain.
Answer: A grazing food chain is a type of food chain that starts from green plants (autotrophs), which constitute the first trophic level. The herbivores form the second trophic level, and predators form the third trophic level.
A detritus food chain is another type that starts with debris detritus produced by green plants.
43. Write a short note on Species.
Answer: Groups of organisms that resemble one another in appearance, behaviour, chemistry, and genetic structure form a species. Organisms of the same species can breed with one another and produce fertile offspring under natural conditions. For instance, all human beings (Homo sapiens) resemble one another in their body structure and systems and have a similar genetic structure, so they are grouped together under the species sapiens.
44. Write a short note on Communities.
Answer: Populations of various species occupying a particular area and interacting with each other make a community. For example, the community of the Kaziranga National Park refers to the rhino population, the elephant population, the cattle population, the grass population, and populations of all kinds of life forms present there. A community comprises several species interacting with each other.
45. Write a short note on Natural ecosystem.
Answer: This is an ecosystem that is found in nature, where there is no interaction with humans. It is a system where everything is in balance, and if one component is removed, the system will fall apart. Natural ecosystems are defined by their habitat. The two major categories are terrestrial and aquatic. Deserts, forests, meadows, prairies, and jungles are terrestrial ecosystems, while aquatic ecosystems include all marine and freshwater systems.
46. Write a short note on Artificial ecosystem.
Answer: Artificial ecosystems are constructed by humans. For example, a pond is built, plants are physically planted around it, and varieties of fish species are released into it. To keep the constructed wetland in balance, human intervention is needed to maintain the ecosystem. Ponds must be kept filled with water so that plants and fish will thrive, invading weeds must be controlled, and predators need to be controlled. It is not a natural ecosystem. Other artificial ecosystems are orchards, large or small gardens, and farms.
47. Write a short note on Abiotic Structure.
Answer: The physical and chemical components of an ecosystem constitute the abiotic structure. It includes all kinds of physical factors like sunlight, latitude and longitudes, average temperature, rainfall pattern, and wind velocity, as well as edaphic (soil) factors. Under chemical components, major nutrients like carbon, nitrogen, phosphorous, oxygen, and potassium, and compounds like carbohydrates, proteins, nucleic acid, and various other organic matters present in soil and water influence the functioning of the ecosystem.
48. Write a short note on Ecological Pyramids.
Answer: The graphical representation of the trophic structure and functions of an ecosystem with producers at the base and successive trophic levels of consumers forming the higher layers (apex) is known as ecological pyramids. Ecological pyramids are of three basic types: the pyramid of numbers, the pyramid of biomass, and the pyramid of energy. Ecological pyramids are used for comparing biomass and energy flow between trophic levels. Such comparisons can be used for identifying or comparing which ecosystems and communities are more efficient in terms of energy transfer.
Extra/additional Fill in the Blanks
1. The word ‘ecology’ is derived from the Greek words oikos and ______
Answer: logos
2. The levels of organization that ecology focuses on are organisms, species, population, communities and ______
Answer: ecosystems
3. An ______ is any form of life, from a single-celled amoeba to a massive banyan tree.
Answer: organism
4. Groups of organisms that can breed with one another and produce fertile offspring form a ______
Answer: species
5. The scientific name for human beings mentioned in the text is ______
Answer: Homo sapiens
6. A ______ is a group of individuals of the same species occupying a given area at a given time.
Answer: population
7. The Rhinoceros unicornis in the ______ National Park, Assam, make a population.
Answer: Kaziranga
8. An ______ is a community of organisms involved in a dynamic network of interactions with non-living components.
Answer: ecosystem
9. According to ______ (1963), the ecosystem is the main active unit of ecology.
Answer: Odum
10. Ecosystems that are free-flowing, like rivers, are known as ______ ecosystems.
Answer: lotic
11. Ecosystems that are of a standing type, like ponds and lakes, are known as ______ ecosystems.
Answer: lentic
12. Cropland ecosystems and fisheries are examples of ______ ecosystems.
Answer: man-made
13. Organisms that can produce their own food, like plants, are known as ______ or producers.
Answer: Autotrophs
14. Organisms that cannot produce their own food and get it from producers are called ______
Answer: Heterotrophs
15. Animals that directly consume producers are called herbivores or ______ consumers.
Answer: primary
16. Carnivores that feed on herbivores are called ______ consumers.
Answer: secondary
17. Organisms that feed on both plants and animals, such as man and fox, are called ______
Answer: Omnivores
18. Organisms that derive their nutrients by decomposing dead plants and biotic compounds are called ______
Answer: decomposers
19. The physical and chemical components of an ecosystem constitute the ______ structure.
Answer: abiotic
20. In an ecosystem, the sequential chain of eating and being eaten is called a ______
Answer: food chain
21. The type of food chain that starts with debris produced by green plants is termed a ______ food chain.
Answer: detritus
22. A network of interlinked food chains is called a ______
Answer: food web
23. Every organism in an ecosystem can be assigned a feeding level, referred to as the ______ level.
Answer: trophic
24. The graphical representation of the trophic structure of an ecosystem is known as an ______ pyramid.
Answer: ecological
25. The pyramid of ______ is based on the total dry weight or total amount of living matter.
Answer: biomass
