๐ฟ Ecosystem – Structure, Function, Producers, Consumers, Energy Flow & Ecological Succession
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๐ฑ What is an Ecosystem?
An ecosystem is a functional unit of nature where living organisms (biotic components) interact with non-living components (abiotic factors) of the environment to meet their life requirements.
Definition
An ecosystem is defined as a self-sustaining natural unit consisting of living organisms and their physical environment, interacting with each other through energy flow and nutrient cycling.
Example
Forest ecosystem
Pond ecosystem
Desert ecosystem
Grassland ecosystem
Marine ecosystem
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๐งฉ Structure of an Ecosystem
Ecosystem structure includes:
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✔ 1. Biotic Components (Living)
(A) Producers / Autotrophs
Green plants, algae, some bacteria
Prepare their own food by photosynthesis
Convert solar energy into chemical energy
Examples:
Grass
Phytoplankton
Trees
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(B) Consumers / Heterotrophs
They depend on other organisms for food
Types:
1️⃣ Primary consumers – herbivores
Examples – deer, cow, grasshopper
2️⃣ Secondary consumers – carnivores
Examples – frog, fox, snake
3️⃣ Tertiary consumers – top carnivores
Examples – lion, tiger, eagle
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(C) Decomposers
Fungi and bacteria
Break down dead organic matter
Convert them into simpler substances
Release nutrients back into the soil
Help in recycling minerals
Example
Rhizopus
Penicillium
Bacteria
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✔ 2. Abiotic Components (Non-living)
These are physical and chemical factors
sunlight
water
air
soil
minerals
temperature
pH
nutrients etc.
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๐ Functional Aspects of Ecosystem
Function of ecosystem includes 4 major processes:
✔ 1. Productivity
Producers prepare biomass through photosynthesis
✔ 2. Energy flow
Energy moves in food chains (sun → producers → consumers)
✔ 3. Nutrient Cycling
Minerals are recycled by decomposers
✔ 4. Ecological Succession
Natural process of gradual change in species composition
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๐ Producers, Consumers and Decomposers
Component Meaning Example
Producers Synthesize food Plants, algae
Consumers Depend on others for food Animals
Decomposers Break dead matter Bacteria, fungi
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๐ฅ Energy Flow in an Ecosystem
Energy flow means transfer of energy from one trophic level to the next.
๐ Energy always flows in one direction
Sun → Producers → Consumers → Decomposers
Trophic levels
1. Producer
2. Primary consumer
3. Secondary consumer
4. Tertiary consumer
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10% Law of Energy Transfer
Proposed by Lindeman
Only 10% energy is available to the next trophic level example: Plants = 1000 units
herbivores receive = 100 units
carnivores receive = 10 units
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Why energy flow is unidirectional?
Because energy cannot be reused again, it is lost as heat at each trophic level.
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๐พ Ecological Succession
Ecological succession is a natural and gradual process through which one biological community replaces another in an ecosystem.
Why does succession occur?
Due to:
natural changes
climate change
availability of water
fire
human activities (deforestation)
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Types of Succession
✔ 1. Primary succession
Occurs on an area where no life existed previously
Example:
new volcanic island
bare rocks
glacier retreat area
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✔ 2. Secondary succession
Occurs where life existed earlier but was destroyed Example:
abandoned farmland
destroyed forest
after flood or fire
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๐ณ Stages of Ecological Succession
1. Pioneer community → first organisms
2. Intermediate community → shrubs, herbs, small plants
3. Climax community → stable forest ecosystem
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๐ Key Points to Remember
Ecosystem includes both living and non-living components
Energy flows in one direction
Nutrients are recycled
Succession leads to formation of a stable climax ecosystem
Decomposers are essential for nutrient cycling
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⭐ Long Answer
๐ฟ Ecosystem, its Structure, Functions, Producers, Consumers, Decomposers, Energy Flow and Ecological Succession
An ecosystem is a basic functional unit of nature in which living organisms interact among themselves and also with the physical environment in which they live. The term ecosystem was first coined by A.G. Tansley. An ecosystem includes both biotic (living) and abiotic (non-living) components. Living organisms depend on abiotic factors like water, soil, light, and temperature for their survival and growth. Forests, ponds, grassland, ocean and deserts are common examples of natural ecosystems.
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⭐ Structure of an Ecosystem
The structure of an ecosystem consists of two main components:
1. Biotic Components
These include all living organisms such as plants, animals and microorganisms.
(a) Producers – They are autotrophs which synthesize food by photosynthesis using sunlight, carbon dioxide and water. They convert solar energy into chemical energy. Example – green plants, phytoplankton and algae.
(b) Consumers – They depend directly or indirectly on plants for food. They are of different types:
• Primary consumers such as grasshopper, goat and deer (herbivores)
• Secondary consumers such as frog, snake and fox (carnivores)
• Tertiary consumers or top carnivores such as lion, tiger and eagle.
(c) Decomposers – These are bacteria and fungi which decompose dead bodies of plants and animals and convert them into simpler substances. They release nutrients back into the environment and help in nutrient cycling.
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2. Abiotic Components
These consist of non-living physical and chemical factors such as air, water, soil, temperature, sunlight, minerals, humidity etc. These factors influence the life processes of organisms present in the ecosystem.
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⭐ Functions of Ecosystem
The ecosystem performs various functions, some of which are as follows:
(i) Productivity
Green plants capture solar energy and convert it into chemical energy through photosynthesis, thereby forming organic matter known as primary productivity.
(ii) Energy Flow
Energy flow refers to the transfer of energy from one trophic level to another through a food chain. It begins with the sun and passes through producers and different levels of consumers. It is always unidirectional.
(iii) Nutrient Cycling
Minerals such as carbon, nitrogen, phosphorus etc. circulate between biotic and abiotic components of the ecosystem. Decomposers play an important role in recycling these nutrients.
(iv) Ecological Succession
Ecosystems continuously change due to climatic and biological factors. Ecological succession refers to a gradual process by which one community of organisms replaces another until a stable climax community is formed.
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⭐ Energy Flow in an Ecosystem
Energy flows from the sun to the producers and then from producers to consumers. At every step, a large part of energy is lost in the form of heat. According to Lindeman’s 10% law, only about ten percent of the energy is transferred from one trophic level to the next, while the rest is lost. Therefore, food chains are generally short having 3–4 trophic levels.
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⭐ Ecological Succession
Ecological succession occurs in the following stages: (1) Pioneer community – first organisms to colonize a barren area
(2) Intermediate stage – herbs, shrubs and small plants appear
(3) Climax community – stable, self-sustaining community forms
Succession may be primary, which starts on a new bare area like a volcanic rock, or secondary, which develops in areas where life existed earlier but was destroyed due to disturbances like fire, flood or human activity.
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⭐ Conclusion
Thus, an ecosystem is a dynamic and self-regulating unit of nature. It maintains the balance of the environment through energy flow, nutrient cycling and ecological succession. Producers, consumers and decomposers are inevitable parts of the ecosystem and together they help in maintaining the continuity of life on Earth.
