Environment and Ecosystem

• Environment refers to all the biotic (living) and abiotic (non-living) components that surround us and affect our life. These components together form an ecosystem.
• The interaction of biotic and abiotic components creates an ecosystem.
• In an ecosystem, organisms are dependent on each other for food, which creates food chains and food webs.
• Due to human activities, environmental degradation is occurring, leading to various issues like the depletion of the ozone layer and waste disposal problems.

Ecosystem

An ecosystem is a system of interactions between biotic and abiotic components. In an ecosystem, all organisms depend on each other for food and energy.

• An ecosystem consists of both biotic (living) and abiotic components, such as temperature, rainfall, air, soil, etc.

There are two types of ecosystems:

(a). Natural Ecosystem - Ecosystems that exist naturally in nature. Example: Forests, oceans, lakes.

(b). Man-made Ecosystem - Ecosystems created by humans. Example: Farmlands, reservoirs, gardens.

(a) Abiotic Components: Abiotic components are the non-living factors in the environment, such as air, water, soil, sunlight, temperature.

(b) Biotic Components: Biotic components are the living organisms, such as plants, animals, microorganisms, fungi.

Classification of Biotic Components Based on Nutrition:

1. Producers:

These are organisms that make their own food. All green plants and blue-green algae use sunlight to make food through photosynthesis.

Example: Green plants, grass, algae in water.

2. Consumers:

These organisms cannot make their own food and depend on producers or other consumers.

Consumers are further classified as:

(i). Herbivores: Animals that eat plants and leaves. Example: Goat, deer.

(ii). Carnivores: Animals that eat meat. Example: Lion, crocodile.

(iii). Omnivores: Animals that eat both plants and meat. Example: Crow, humans.

(iv). Parasites: Organisms that live on or inside other organisms to feed on them. Example: Lice, mistletoe.

3. Decomposers: Fungi and bacteria that break down dead plants and animals into simpler substances, helping to recycle nutrients in the ecosystem.

Food Chain

A food chain is a sequence where one organism eats another in order to obtain food.

Example: 🌿 Grass → 🦌Deer → 🦁Lion.

• In a food chain, the levels through which energy is transferred are known as trophic levels.
• Energy flows in one direction in a food chain. Green plants absorb 1% of the sunlight, which is used in photosynthesis to make food.
• The 10% rule states that only 10% of the energy is transferred from one trophic level to the next, while the remaining 90% is used by the organisms at that level for their metabolic processes.
• Typically, food chains have only 3 or 4 trophic levels because very little energy is available for higher levels.

Biomagnification

Biomagnification refers to the increase in the concentration of harmful chemicals as they move up the food chain.

• These chemicals accumulate at higher levels in organisms, particularly in humans.

Food Web

A food web is a network of interconnected food chains. In a food web, one organism can depend on multiple others for food, forming a complex web of interactions.

Example:

🌱Grass → 🐇 Rabbit → 🦅Hawk

🌱Grass → 🦌Deer → 🦁Lion

🌿 Plants → 🐛Insects → 🐦Birds → 🐍Snake → 🦅Eagle

🌿 Plants → 🐛Insects → 🐸Frog → 🐍Snake → 🐅Tiger

An organism like a hawk or lion can be part of several food chains in a food web.

Environmental Issues

Changes in the environment affect us, and our activities also impact the environment. Over time, this causes environmental degradation and leads to various environmental issues such as pollution and deforestation.

Ozone Layer:

The ozone layer is a protective layer of ozone (O₃) surrounding the Earth. It absorbs harmful ultraviolet (UV) rays from the sun, protecting living organisms from health issues like skin cancer, cataracts, weakened immune systems, and damage to plants.

• The ozone layer is mainly found in the stratosphere, a part of the Earth's atmosphere. At ground level, ozone is a harmful pollutant.

Ozone Formation Process:

1. Photodissociation:

When UV rays from the sun strike oxygen (O₂) molecules, they split into two oxygen atoms (O).

O₂ + UV → O + O

2. Ozone Formation:

The free oxygen atoms (O) combine with other O₂ molecules to form ozone (O₃).

O + O₂ → O₃

3. Ozone Breakdown:

UV-B rays break down ozone (O₃) into oxygen molecules and free oxygen atoms.

O₃ + UV → O₂ + O

Ozone Layer Depletion:

• In 1985, a significant thinning of the ozone layer was observed over Antarctica, known as the ozone hole.
• The primary cause of the depletion of the ozone layer was found to be human-made chemicals called CFCs (chlorofluorocarbons), used in refrigeration, air conditioning, and firefighting.
• In 1987, the Montreal Protocol was signed to limit the production of CFCs.

Waste Management

Today, waste disposal is a significant problem affecting the environment. The large amount of waste generated by our lifestyles causes environmental pollution.

Types of Waste:

(a). Biodegradable Waste: Waste that decomposes naturally with the help of microorganisms.

Example: Fruit and vegetable peels, cotton fabric, jute, paper.

(b). Non-biodegradable Waste: Waste that does not decompose naturally.

Example: Plastics, polythene, synthetic fibers, metals, radioactive waste.

 Difference between Biodegradable Waste & Non-biodegradable Waste

Waste Management Methods:

• Biomass Plants: Biodegradable waste is converted into compost and fertilizers by biomass plants.
• Sewage Treatment: Sewage treatment plants purify wastewater before it is released into rivers or lakes.
• Landfills: Waste is dumped in low-lying areas and compacted to reduce volume.
• Composting: Organic waste is placed in compost pits, covered with soil, and over time, it decomposes into compost.
• Recycling: Non-biodegradable waste is processed and converted into reusable materials.
• Reuse: Reusing items for a different purpose, such as using old newspapers to make envelopes.