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NCERT Solutions for Class 12 Biology Chapter 12 - Ecosystem

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NCERT Solutions for Class 12 Biology Chapter 12 - Ecosystem - Free PDF

Chapter 12, Ecosystems is one of the most important and scoring topics covered in the Class 12 Biology syllabus. The NCERT Solutions for Class 12 Biology Chapter 12 are prepared in a simple manner by our subject-matter experts to help you learn the topics covered in this chapter easily. These solutions are available in the PDF format on Vedantu. You can download the PDF file for free. By referring to these NCERT Solutions, you can revise chapter 12 of Class 12 Biology thoroughly and secure good marks in the exams.

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Table of Content
1. NCERT Solutions for Class 12 Biology Chapter 12 - Ecosystem - Free PDF
2. Access NCERT Solution for Class 12 Biology Chapter 12 -Ecosystem
3. NCERT Solutions for Biology Class 12 Chapter 12 - Ecosystem
    3.1Ecosystem Class 12 NCERT PDF Explanation
    3.2NCERT Solutions for Biology Class 12 Chapter 12 Weightage
4. Important Topics in NCERT Solutions Class 12 Biology Chapter Ecosystem
    4.1NCERT Solutions of Ecosystem Class 12 Benefits
5. Conclusion 
FAQs


Class:

NCERT Solutions for Class 12

Subject:

Class 12 Biology

Chapter Name:

Chapter 12 - Ecosystem

Content-Type:

Text, Videos, Images and PDF Format

Academic Year:

2024-25

Medium:

English and Hindi

Available Materials:

  • Chapter Wise

  • Exercise Wise

Other Materials

  • Important Questions

  • Revision Notes



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Ecosystem Chapter at a Glance - Class 12 NCERT Solutions


Ecosystem


Ecosystem

Competitive Exams after 12th Science
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Access NCERT Solution for Class 12 Biology Chapter 12 -Ecosystem

1. Fill in the blanks.

(a) Plants are called as_________ because they fix carbon dioxide. 

(b) In an ecosystem dominated by trees, the pyramid (of numbers) is _________ type. 

(c) In aquatic ecosystems, the limiting factor for productivity is _________. 

(d) Common detritivores in our ecosystem are_________.

(e) The major reservoir of carbon on earth is_________.
Ans.

(a) Plants are called autotrophs because they fix carbon dioxide. 

(b) In an ecosystem dominated by trees, the pyramid (of numbers) is of inverted type. 

(c) In aquatic ecosystems, the limiting factor for productivity is light.

(d) Common detritivores in our ecosystem are earthworms

(e) A major reservoir of carbon on Earth is the oceans.


2. Which one of the following has the largest population in a food chain? 

(a) Producers 

(b) Primary consumers

(c) Secondary consumers 

(d) Decomposers 

Ans.

(d) Decomposers 

Decomposers include microorganisms like bacteria and fungi. The largest population is formed by them in a food chain and they obtain nutrients by breaking down the remains of dead plants and animals.


3. The second trophic level in a lake is

(a) Phytoplankton

(b) Zooplankton

(c) Benthos

(d) Fishes

Ans.

(b) Zooplankton

Primary consumers are at the level of Second trophic. These are the organisms that eat the primary producers. Zooplankton is also one of them. They are the primary consumers in aquatic food chains that feed upon phytoplankton and efficiently digest plant matter for energy. 


4.  Secondary producers are 

(a) Herbivores

(b) Producers

(c) Carnivores

(d) None of the above 

Ans.

(d) None of the above.

Plants are the only producers and they lie at the lowest trophic level. Thus, they are called primary producers. There are no other producers in the food chain. 


5. What is the percentage of photosynthetically active radiation (PAR), in the incident solar radiation. 

(a) 100% 

(b) 50 % 

(c) 1-5% 

(d) 2-10%

Ans.

(b) 50% 

About fifty percent of total incident solar radiation forms photosynthetically active radiation of PAR. 


6.  Distinguish between 

(a) Grazing food chain and detritus food chain

(b) Production and decomposition 

(c) Upright and inverted pyramid 

(d) Food chain and Food web

(e) Litter and detritus

(f) Primary and secondary productivity

Ans. The difference between the grazing food chain and the detritus food chain are: 

Grazing food chain

Detritus food chain

1.

Energy is derived from the Sun in the grazing food chain.

1.

Energy comes from organic matter which is generated in trophic levels of the grazing food

chain.

2.

It starts with the producers,available at the first trophic level. The plant biomass is then eaten by herbivores, which successively are consumed by a spread of carnivores.

2.

It starts with detritus like dead bodies of animals or fallen leaves, which are then consumed by decomposers or detritivores. These detritivores are in turn eaten by their predators.

3.

This food chain is a large one.

3.

Detritus food chain is smaller as compared to the

grazing food chain.


The difference between Production and decomposition are: 

Production

Decomposition

1.

It is the rate of organic matter produced by producers.

1.

Breaking down of complex organic matter with the help of decomposers from the body of dead plants and animals and converting into organic raw materials like CO2, H2O, and other nutrients.

2.

It is dependent on the photosynthetic capacity of the producers. 

2.

It occurs with the help of decomposers.

3.

The requirement of sunlight is necessary by plants for primary production. 

3.

No sunlight requirement is there in the process of decomposition. 


The difference between the upright and inverted pyramid are: 

Upright pyramid

Inverted pyramid

1.

The pyramid of energy is always upright.

1.

The pyramid of biomass and the

a pyramid of numbers can be inverted.


2.

The number and biomass of organisms in the producer level of an ecosystem are the highest in an upright pyramid, which further keeps on decreasing at each trophic level in a food chain.


2.

The number and biomass of organisms in the producer level of an ecosystem is the lowest in an inverted pyramid, which further keeps on increasing at each trophic level.


The difference between the Food chain and the Foodweb is: 

Food chain

Food Web

1.

It is a single linear sequence of

organisms.


1.

It is a network formed by interconnecting food chains.


2.

In this chain, members are present at higher trophic levels which sustain single types of organisms.


2.

Alternate food sources are present in one organism.


Difference between Litter and detritus are: 

Litter

Detritus

1.

Litter is all the wastes that are produced above the ground.

1.

Detritus is the remains of dead plants and animals in an ecosystem.

2. 

Litter consists of both biodegradable and non-biodegradable matter.

2.

Detritus consists of only biodegradable matter. 


The difference between Primary and secondary productivity are: 

Primary Productivity

Secondary productivity

1. 

It is defined as the rate at which organic energy is stored as organic matter produced by producers per unit

the area over a period of time.

1.

It is defined as the rate of production of organic matter by consumers over a period of time.



7. Describe the components of an ecosystem.

Ans. An ecosystem creates a link that has both the biological community as well as the non-living components of an area. The ecosystem was defined as the living world and its habitat by A.G. Tansley. It meant that any habitat on the earth which includes plants, animals, and non-living substances interact to produce materials that can be exchanged between living and nonliving components of the habitat in an ecosystem. Thus, they perform as a unit, which gets conspicuous during the processes of nutrient cycling, energy flow, decomposition, and productivity. Many ecosystems like ponds, forests, grasslands, etc are there. 

The two components of an ecosystem are:

  • Biotic Component: The living component of an ecosystem is the biotic component. Which includes biotic factors such as producers, consumers, decomposers, etc. It is divided into major groups:

(a) Producers are green plants that include plants and algae. The presence of chlorophyll pigment, helps them carry out the process of photosynthesis in the presence of light. Thus, they are also referred to as converters or transducers. 

(b) Consumers or heterotrophs are organisms that cannot manufacture food and are, therefore, directly (primary consumers) or indirectly (secondary and tertiary consumers) dependent on producers for their food.

(c) Decomposers are the microorganisms like bacteria and fungi. The largest population is contributed by them in a food chain by breaking down the remains of dead plants and animals, and nutrients are obtained. 

  • Abiotic component: These are the nonliving components within an ecosystem such as light, temperature, water, soil, air, inorganic nutrients, etc.


8. Define ecological pyramids and describe with examples, pyramids of number and biomass.

Ans. An ecological pyramid is a graphical representation of the number, biomass, and energy of the successive trophic levels of an ecosystem. In an ecological pyramid, the lowermost trophic level is formed by the producers and the topmost level is that of carnivores. 

There are three types of pyramids:

  • Pyramid of numbers

  • Pyramid of energy

  • Pyramid of biomass

The pyramid of numbers illustrates the relationship between producers, herbivores, and carnivores in an ecosystem. It can be either upright or inverted based on the number of producers. In a grassland ecosystem, grasses act as producers, making the pyramid upright. In this food chain, the number of individuals is highest at the producer level and decreases as we move up to tertiary carnivores like eagles.


Pyramid of Numbers


Pyramid of Numbers


On the flip side, in a parasitic food chain, the pyramid of numbers is upside-down. In this setup, a single tree (the producer) supports various fruit-eating birds, and these birds, in turn, sustain multiple insect species.


Biomass pyramid depicts the total living matter at each trophic level in an ecosystem, whether it's higher or lower. In grasslands and forests, it's upright, indicating more biomass at the producer level than the top carnivore level. Conversely, in pond ecosystems, it's inverted, showcasing fishes' biomass surpassing that of zooplankton they consume.


9. What is primary productivity, and what factors influence it?

Ans: Primary productivity refers to the organic matter produced by producers per unit area over time. Environmental factors like light, temperature, water, and precipitation, along with nutrient availability and plant access for photosynthesis, determine an ecosystem's primary productivity.


10. Q: What is decomposition, and what does it involve?

Ans: Decomposition is when decomposers break down complex organic matter from dead plants and animals into inorganic substances like carbon dioxide, water, and nutrients. The processes involved in decomposition are as follows:


Fragmentation: The first step in the process of decomposition is fragmentation. By the action of detritivores, there is a breakdown of detritus into smaller pieces like in earthworms is called fragmentation.

Leaching: Several water-soluble inorganic substances percolate into the deeper layers of soil along with rain or irrigation water, it is known as leaching.  

Catabolism: Bacteria and fungi degrade detritus through various enzymes into smaller pieces is called catabolism.

Humification: is the creation of a dark, finely divided substance known as humus. This acts like a nutrient reservoir for plants.

Mineralization: By the action of microbes, humus is further degraded which finally results in the release of inorganic nutrients into the soil. 


A dark-colored, nutrient-rich substance called humus is produced by the process of decomposition. Humus thus degrades and releases inorganic raw materials such as CO2, water, and other nutrients from the soil.


11. Give an account of the energy flow in an ecosystem?

Ans. In ecosystems, energy follows a one-way path, entering living things from the physical world, passing between organisms, and eventually returning to the environment in a less useful form. Solar energy enters through the Sun, absorbed by Earth's surface for photosynthesis and maintaining temperatures. Green plants capture a small portion (2-10%) of solar energy for photosynthesis. This energy, called gross primary productivity, is used for plant respiration. When herbivores consume plants, only 10% of the stored energy is transferred, with 90% used for various processes. Similarly, only 10% of herbivores' energy is transferred to carnivores. This pattern, known as the ten percent law of energy flow, highlights the gradual loss of energy as it moves through different trophic levels in an ecosystem.


Flow of Energy


Flow of Energy


12. Write the important features of a sedimentary cycle in an ecosystem?

Ans. Sedimentary cycles have their reservoir pool in deep sediments or in the earth’s crust or rocks. Nutrient elements that are found in the sediments of the Earth are Sulphur, phosphorus, potassium, and calcium. There is absence of a gaseous phase in this cycle.

This cycle is very slow.  A  longer period of time is taken to complete their circulation and is considered a less perfect cycle. Since, In the process of recycling, nutrient elements get locked in the reservoir pool, which thereby takes a long time to come out and continue circulation. Thus, it always goes out of circulation for an extended time.


13. Outline the salient features of carbon cycling in an ecosystem.

Ans. An essential cycle in nature is the carbon cycle, with the atmosphere as its main reservoir. Carbon is a crucial element in all living organisms, forming the backbone of organic components like carbohydrates, lipids, and proteins. Through photosynthesis, sunlight and carbon dioxide create glucose, a carbon compound, entering living organisms. Recycling is vital, and processes like respiration and decomposition release carbon dioxide back into the atmosphere. In respiration, glucose is broken down, producing carbon dioxide. Decomposition releases carbon dioxide from dead plants and animals. Additionally, human activities like industrialization, fuel combustion, deforestation, volcanic eruptions, and forest fires contribute significantly to carbon dioxide levels in the atmosphere. Understanding the carbon cycle helps us comprehend how this essential element moves through living organisms and the environment, emphasizing the interconnectedness of all living things and their dependence on natural processes.


Carbon Cycle


Carbon Cycle


NCERT Solutions for Biology Class 12 Chapter 12 - Ecosystem

Class 12's Ecosystem chapter delves into vital ecology topics, a key part of the Biology syllabus. Covered in NCERT Ch 12, it explores Ecosystem Structure and Function, Productivity, Decomposition, Energy Flow, Ecological Pyramids, Ecological Succession, Nutrient Cycling, and Ecosystem Services. These subjects enable students to grasp the complexities of Earth's ecosystems, offering insights into their structures and functions.


Ecosystem Class 12 NCERT PDF Explanation

This summary covers the Class 12 NCERT Chapter 12, "Ecosystem." It breaks down the ecosystem's structure and functions, distinguishing between terrestrial and aquatic ecosystems. The PDF elaborates on different types of productivity and the intricate process of decomposition. Exploring Energy Flow, the chapter delves into food chains, detailing producers and consumers, culminating in an Ecological Pyramid. Ecological Successions are explained, particularly in plant contexts, followed by insights into Nutrient Cycles—specifically, the Nitrogen and Phosphorus Cycles. Finally, Ecosystem Services are discussed in the NCERT Solution for Chapter 12, offering a comprehensive understanding of these essential elements in the study of ecosystems on Earth.


NCERT Solutions for Biology Class 12 Chapter 12 Weightage

The chapter Ecosystem is part of Unit X of the class 12 NCERT Biology textbook, Ecology and Environment. Unit X of the book has a total of 4 chapters and Ecosystem is the second chapter of the unit. Unit X carries a total of 14 marks, split into four chapters including Ecosystem itself. The weightage of chapter 12 is 3.5 marks for the Class 12 final examination of Biology, if questions are asked from all the chapters in this unit. The marks allotment may vary depending on the question format of the examination.


Important Topics in NCERT Solutions Class 12 Biology Chapter Ecosystem

In Class 12 Biology Chapter 12 Ecosystem, students will get a detailed explanation of the following topics:


  • Structure and Function of Ecosystem

  • Decomposition

  • Energy Flow

  • Ecological Succession

  • Productivity

  • Ecological Pyramids

  • Nutrient Cycling

  • Ecosystem Services


All of these topics are important for the Class 12 Biology exam; therefore, one must go through these topics in detail and clear their doubts beforehand.


NCERT Solutions of Ecosystem Class 12 Benefits

NCERT Biology's chapter 12 for class 12 is very scoring from the examination point-of-view. The benefits of the NCERT Solutions for Class 12 Biology's Chapter 12 (Ecosystem) are as follows.


  • The NCERT Solutions for Biology Class 12 Chapter 12 (Ecosystem) facilitates a holistic understanding of the topics covered in the chapter.  

  • By referring to the NCERT Solutions for Ecosystem you will be able to learn the appropriate answer pattern for the Class 12 Biology exam.

  • The NCERT Solutions for Class 12 Chapter 12; Ecosystems, make an excellent resource for self-study and revision purposes. Therefore saving a lot of time during the exams.

  • Since these solutions are available in a PDF format, you can consult them even when you are not connected to the internet.


Explore Study Materials for Class 12 Chapter 12 - Ecosystem


Access Other Chapters of NCERT Solutions for Class 12 Biology


Other Related Links for Class 12 Biology



Conclusion 

The Ecosystem chapter teaches us about the way different living things in our world connect and depend on each other. It looks at the parts of ecosystems, how energy moves through them, and how new life takes over from old life. We also learn how things like carbon and water move around the planet, and how we can affect these processes. The chapter reminds us that everything in nature is linked, and we need to take care of it for ourselves and the future. It asks us to make good choices and protect the variety of life and the Earth’s materials that keep us alive. Learning about ecosystems helps us deal with environmental problems and live in harmony with nature.

FAQs on NCERT Solutions for Class 12 Biology Chapter 12 - Ecosystem

1. What are the Important Topics Covered in the Ecosystem Class 12 NCERT PDFs?

All the topics in the chapter Ecosystem Class 12 NCERT PDFs are of equal importance. Here is a list of all the important topics in the chapter.

  • Structure and Functions of Ecosystems, 

  • Patterns and Components of Ecosystems, 

  • Productivity, 

  • Decomposition, 

  • Energy Flow, 

  • Ecological Pyramid, 

  • Biomass, 

  • Energy, 

  • Nutrient Cycles (of Carbon and Phosphorous), 

  • Ecological Succession 

  • Ecological Services (carbon fixation, pollination, seed dispersal, and oxygen release). 

These topics are explained in detail for the best understanding of the students in the NCERT Solutions for Class 12 Biology's Chapter 12, available on Vedantu.

2. Are the NCERT Solutions for Class 12 Biology's Chapter 12 Beneficial for Exam Preparation?

The NCERT solutions for class 12 Biology's Chapter 12 will help you to understand the chapter very well. In case you have some doubts for answering the questions given in the chapter and it becomes extremely difficult to understand the concepts properly, these NCERT Solutions will help you to address your doubts. All the topics covered in the 12th chapter of Class 12 NCERT Biology are thoroughly explained in the solutions.

3. Where can I get the accurate solution for NCERT Solutions for Class 12 Biology Chapter 12?

Vedantu offers accurate and easy to understand NCERT Solutions for Class 12 Biology, Chapter 12. These solutions are crafted by the experts in Vedantu which provides authentic and knowledgeable information in a simplified manner. Visit the Vedantu website (vedantu.com) to download the free NCERT solutions PDF to learn and understand the concepts to ace your exams. 

4. What are the topics covered in Chapter 12, Biology Class 12?

The topics covered are: 

  • Ecosystem–Structure and Function

  • Productivity

  • Decomposition

  • Energy Flow

  • Ecological Pyramids

  • Ecological Succession

  • Nutrient Cycling

  • Ecosystem Services

To gain more knowledge on the mentioned topics, visit the Vedantu website and the app. It will provide you a deeper insight into this chapter. Students are advised to make use of the NCERT Solutions offered by the Vedantu to help them do well in their exams.

5. How important is Chapter 12 Of Class 12 Biology for board exams?

Ecosystem is one of the important topics and is given a lot of weightage in the board exams. Since the chapter is easily understandable, it will be easier for the students to answer the NCERT questions. Download the important questions PDF at the Vedantu Website or the app for free of cost.

6 .  Which questions and answers are important in Chapter 12, Class 12 Biology?

Vedantu provides a series of important questions and answers. Visit the Vedantu website to download a PDF of important questions for Chapter 12, Class 12 Biology. These questions are crafted by the experts at Vedantu to make the revision easier for the students. With the NCERT Solutions provided by the Vedantu, students will get well versed in this chapter and excel in the exams.

7.  What is Chapter 12 of Class 12 Biology all about

Students will learn about the structure and functions of an ecosystem. It will take you through the terrestrial and aquatic ecosystems too. You will also learn about Energy Flow, Ecosystem, and the Ecological Pyramid. Ecological Successions, Nitrogen Cycle and Phosphorus Cycle. To get in-depth knowledge, it is better for the students to get the help of NCERT Solutions. Visit the website to register for online live classes and download the PDF of NCERT solutions of Chapter 12 to revise and practice for the exams. Download the important questions at the Vedantu Website or the app for free of cost too.