ENVIRONMENTAL STUDIES

ENVIRONMENTAL STUDIES

Renewable and Non-Renewable Natural Resources

A. Renewable Resources

·       Resources that can be naturally regenerated or replenished within a relatively short period.

1. Solar Energy

• Energy obtained from the Sun.
• It is virtually inexhaustible on a human time scale.
• Used for:
• Solar panels
• Solar water heaters
• Solar cookers
• Electricity generation

2. Wind Energy

• Energy produced by moving air.
• Wind turbines convert wind energy into electricity.
• Advantages:
• Clean
• Renewable
• Low operational pollution

3. Water

• Water is continuously renewed through the water cycle.
• Major processes:
• Evaporation
• Condensation
• Precipitation

4. Forest Resources

Forests provide:

• Timber
• Fuelwood
• Fruits
• Medicinal plants

5. Biomass

• Organic material obtained from plants and animals.
• Examples:
• Wood
• Agricultural residues
• Animal waste
• Can be used to produce energy.

B. Non-Renewable Resources

• Resources available in limited quantities.
• They take very long geological periods to form.
• Their consumption is generally much faster than their natural formation.

Coal

• Formed from ancient plant material under pressure and heat.
• Major uses:
• Electricity generation
• Industries
• Steel production

Petroleum

• Formed from ancient organic matter over millions of years.
• Used for:
• Petrol
• Diesel
• Kerosene
• Lubricants
• Petrochemicals

Natural Gas

• Mainly consists of methane.
• Used for:
• Cooking
• Electricity generation
• Industrial purposes
• Transportation

Ecosystem — Concept, Structure and Functions

Meaning of Ecosystem

• An ecosystem is a functional unit in which living organisms interact with one another and with their physical environment.
• The term ecosystem was introduced by A.G. Tansley in 1935.

Simple concept

Ecosystem = Living components + Non-living components + Interaction

 

Components of an Ecosystem

A. Abiotic Components

These are the non-living components.

Examples

• Sunlight
• Temperature
• Water
• Air
• Soil
• Minerals
• Humidity
• pH
• Nutrients

B. Biotic Components

These are the living components.

1. Producers

• Producers make their own food.
• They mainly use sunlight to make food.
• Examples: Green plants, algae.
• They are the first trophic level.

Producer = Makes food

2. Consumers

• Consumers cannot make their own food.
• They get food by eating plants or other animals.
• Examples: Cow, deer, tiger, humans.

Consumer = Eats food

3. Decomposers

• Decomposers break down dead plants, dead animals and waste materials.
• They convert them into simpler substances and return nutrients to the environment.
• Examples: Bacteria and fungi.

Decomposer = Breaks down dead matter

Types of Ecosystem

Terrestrial

• Forest
• Grassland
• Desert

Aquatic

• Pond
• Lake
• River
• Ocean
• Wetland

Artificial Ecosystems

• Crop field
• Garden
• Aquarium
• Artificial pond

Structure of Ecosystem

1. Abiotic components

↓

2. Producers

↓

3. Consumers

↓

4. Decomposers

↓

5. Energy flow and nutrient cycling

Functions of Ecosystem

1. Energy Flow

• Energy enters the ecosystem mainly through sunlight.
• Producers capture solar energy through photosynthesis.
• Energy then passes through different trophic levels.

2. Nutrient Cycling

Important nutrients continuously circulate between living and non-living components.

Examples:

• Carbon cycle
• Nitrogen cycle
• Phosphorus cycle
• Water cycle

3. Decomposition

• Dead plants and animals are broken down by decomposers.
• Nutrients are returned to the environment.

4. Productivity

• Ecosystems produce organic matter through producers.

5. Ecological Regulation

Ecosystems help regulate:

• Climate
• Water
• Soil
• Atmospheric gases
• Population levels

6. Habitat Provision

• Ecosystems provide food, shelter and breeding places for organisms.

Food Chain

Definition

·       A food chain is a sequence of organisms through which food, nutrients and energy are transferred from one organism to another.

Basic pattern

Producer → Primary Consumer → Secondary Consumer → Tertiary Consumer

Example

Grass → Grasshopper → Frog → Snake → Eagle

Trophic Level

·       Each feeding position in a food chain is called a trophic level.

Trophic levels

1st trophic level

• Producers

2nd trophic level

• Primary consumers

3rd trophic level

• Secondary consumers

4th trophic level

• Tertiary consumers

Types of Food Chain

A. Grazing Food Chain

Begins with living green plants.

Plants → Herbivores → Carnivores

Example:

Grass → Deer → Tiger

B. Detritus Food Chain

Begins with dead organic matter.

Dead organic matter → Detritivores/Decomposers → Consumers

Example:

Dead leaves → Earthworm → Bird

Importance of Food Chain

• Transfers energy.
• Transfers nutrients.
• Shows feeding relationships.
• Maintains ecological balance.
• Helps understand trophic levels.
• Controls populations.

Energy Flow in Ecosystem

Meaning

·       Energy flow refers to the movement of energy through different components and trophic levels of an ecosystem.

Source of Energy

For most ecosystems:

Sun → Producers → Consumers → Decomposers

• Solar energy is captured by producers through photosynthesis.
• Energy is then transferred through food relationships.

One-Way Flow of Energy

Energy flow is unidirectional.

It does NOT cycle.

The general pathway is:

Sun → Producers → Primary Consumers → Secondary Consumers → Tertiary Consumers

At every transfer, some energy is lost mainly as heat.

10% Law

According to Lindeman's 10% law:

• Approximately 10% of the energy at one trophic level is transferred to the next trophic level.
• The remaining energy is largely lost through metabolic activities, respiration and heat.

Example

If producers contain:

10,000 units

Then approximately:

• Primary consumers → 1,000 units
• Secondary consumers → 100 units
• Tertiary consumers → 10 units

Consequence

• Higher trophic levels contain less available energy.
• Food chains generally cannot have many trophic levels.

Energy Flow vs Nutrient Cycling

Energy	Nutrients
Flows through ecosystem	Cycle through ecosystem
Mainly enters as solar energy	Obtained from environment
One-way movement	Repeated circulation
Eventually dissipated as heat	Reused by organisms

 

Ecological Pyramids

Definition

·       An ecological pyramid is a graphical representation of the relationship between organisms at different trophic levels.

It can represent:

1. Number
2. Biomass
3. Energy

Pyramid of Numbers

·       Shows the number of organisms present at each trophic level.

Example

Grass → Grasshopper → Frog → Snake

• Many grasses
• Fewer grasshoppers
• Fewer frogs
• Fewer snakes

Important point

The pyramid may be:

• Upright
• Inverted

Pyramid of Biomass

·       Shows the total mass of living organisms at each trophic level.

Biomass

·       The total biological mass of organisms present at a trophic level.

Usually

·       Terrestrial ecosystems → generally upright.

Aquatic ecosystems

·       May show an inverted biomass pyramid, especially where phytoplankton have a low standing biomass but high turnover.

Pyramid of Energy

·       Shows the amount of energy available at each trophic level.

Characteristics

• Always upright.
• Energy decreases at successive trophic levels.
• Represents energy transfer through the ecosystem.

Pyramid of energy can never be inverted.

 

Conservation of Biodiversity

Biodiversity

·       Biodiversity means the variety and variability of life on Earth.

Levels of Biodiversity

1. Genetic Diversity

Variation in genes within a species.

Example

Different varieties of:

• Rice
• Wheat
• Mango

2. Species Diversity

Variety of different species in a particular area.

Example

A forest may contain:

• Trees
• Birds
• Mammals
• Reptiles
• Insects
• Fungi

3. Ecosystem Diversity

Variety of ecosystems within a region.

Examples

• Forests
• Grasslands
• Wetlands
• Deserts
• Rivers
• Oceans

Importance of Biodiversity

Ecological importance

• Maintains ecosystem stability.
• Supports food chains.
• Helps nutrient cycling.
• Maintains ecological processes.

Economic importance

Provides:

• Food
• Timber
• Medicines
• Fibres
• Fuel
• Raw materials

Scientific importance

• Supports research.
• Provides genetic resources.
• Helps develop medicines and crops.

Social and cultural importance

• Supports traditional practices.
• Has cultural and recreational value.

Major Threats to Biodiversity

1. Habitat Loss

• Destruction or modification of natural habitats.
• Major cause of species decline.

2. Overexploitation

Excessive use of biological resources.

Examples:

• Overfishing
• Excessive hunting
• Excessive logging

3. Pollution

• Air pollution
• Water pollution
• Soil pollution
• Plastic pollution

4. Invasive Alien Species

·       Non-native species that negatively affect native species or ecosystems.

5. Climate Change

Can alter:

• Temperature
• Rainfall
• Habitats
• Species distribution

6. Illegal Wildlife Trade

• Hunting and trafficking of animals and plants.

Biodiversity conservation 

Protection, management and sustainable use of biological diversity.

1.  In-situ Conservation

·       In-situ conservation means conserving organisms within their natural habitats.

Simple meaning

"Protect the species where it naturally lives."

Examples

National Parks

·       Areas protected primarily for conservation of wildlife and ecosystems.

Examples:

• Jim Corbett National Park
• Kaziranga National Park
• Ranthambore National Park

Wildlife Sanctuaries

·       Areas where wildlife and their habitats receive legal protection, with certain regulated human activities depending on the applicable rules.

Biosphere Reserves

Large areas designed to promote:

• Conservation
• Sustainable development
• Research
• Education

Advantages of In-situ Conservation

• Protects organisms in their natural environment.
• Conserves entire ecosystems.
• Protects natural interactions.
• Maintains evolutionary processes.
• Protects multiple species simultaneously.
• Maintains natural genetic diversity.

Ex-situ Conservation

·       Ex-situ conservation means conserving species outside their natural habitats under controlled or managed conditions.

Simple meaning

"Protect the species outside its natural habitat."

Examples

1. Zoos

• Maintain and breed wild animals under managed conditions.

2. Botanical Gardens

• Maintain collections of living plants.

3. Seed Banks

• Store seeds for future conservation and use.

4. Gene Banks

• Preserve genetic material.

5. Cryopreservation

• Biological material is preserved at extremely low temperatures.

Examples:

• Seeds
• Sperm
• Oocytes
• Embryos
• Plant tissues

6. Captive Breeding

• Breeding endangered species under controlled conditions.
• Individuals may later be used for conservation or reintroduction programmes where appropriate.

Advantages of Ex-situ Conservation

• Protects endangered species from immediate threats.
• Allows controlled breeding.
• Facilitates scientific research.
• Provides long-term storage of genetic material.
• Can support reintroduction into natural habitats.

Limitations

• Expensive.
• Requires specialized facilities.
• Limited number of individuals can be maintained.
• Natural ecological interactions may not be fully maintained.
• Genetic diversity can become limited if populations are too small.

Video Description

v  Don’t forget to do these things if you get benefitted from this article

v  Visit our Let’s contribute page https://keedainformation.blogspot.com/p/lets-contribute.html

v  Follow our page

v  Like & comment on our post

·