Life on the earth is found almost everywhere. Living organisms are�found from the poles to the equator, from the bottom of the sea to several km in the air, from freezing waters to dry valleys, from under the sea to underground water lying below the earth’s surface.

BIOSPHERE

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The biosphere is one of the four layers that surround the Earth along with the lithosphere (rock), hydrosphere (water) and atmosphere (air) and it is the sum of all the ecosystems. The biosphere is unique. So far there has been no existence of life elsewhere in the universe.

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COMPONENTS OF BIOSPHERE

1. Abiotic Components: consists of all non-living elements which are essential for the survival of all living organisms.
2. Biotic Components: 1. Plants

2. Animals

3. Micro-organism

III Energy: essential for reproduction and generation of all biological life on Earth.

ECOLOGY

• A German zoologist Ernst Haeckel, who used the term as ‘oekologie’ in 1869, became the first person to use the term ‘ecology’
• The term ecology is derived from the Greek word ‘oikos’ meaning ‘house’, combined with the word ‘logy’ meaning the ‘science of’ or ‘the study of ’.
•  Ecology is the study of how organisms interact with one another and with their physical environment.

HABITAT

In ecology, a habitat is the type of natural environment in which a particular species of organism lives. A species’ habitat is those places where the species can find food, shelter, protection, and mates for reproduction It is characterized by both physical and biological features.

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ECOSYSTEM

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An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system.

The term ecosystem was first used by A. G. Tansley in 1935.

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FACTORS OF ECOSYSTEM

TYPES OF ECOSYSTEM

FOOD CHAIN

A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another. In a food chain, each organism occupies a different tropic level, defined by how many energy transfers separate it from the basic input of the chain.

TYPES OF FOOD CHAIN

1. Grazing food chain: This type of food chain starts from the living green plants goes to grazing herbivores, and on to carnivores.
2. Detritus food chain: Detritus food chain is the type of food chain that starts with dead organic materials.

FOOD WEB

Food web is a network of interconnected food chains. It comprises all the food chains within a single ecosystem. It helps in understanding that plants lay the foundation of all the food chains. In a marine environment, phytoplankton forms the primary producer.

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BIOMES

A biome is a plant and animal community that covers a large geographical area determined mainly by climate. Therefore, a biome can be defined as the total assemblage of plant and animal species interacting within specific conditions. These include rainfall, temperature, humidity and soil conditions. Some of the major biomes of the world are: forest, grassland, desert and tundra biomes.

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BIOGEOCHEMICAL CYCLE

“Biogeochemical cycles mainly refer to the movement of nutrients and other elements between biotic and abiotic factors.”

The term biogeochemical is derived from “bio” meaning biosphere, “geo” meaning the geological components and “chemical” meaning the elements that move through a cycle.

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Water Cycle

Carbon Cycle

Oxygen Cycle

Nitrogen Cycle

ECOLOGICAL BALANCE

• The ecological systems are usually in a stable equilibrium or homeostasis.
• Small change will be corrected by some negative feedback.
• Certain species compete with one another determined by the environment in which they grow.
• some species depend on others for their food and sustenance.
• In the case of plants, any disturbance in the native forests brings about a change in the species distribution which is called the succession.

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CONT….

Ecological imbalance may cause adverse effects to the general environment like floods, landslides, diseases, erratic climatic occurrences, etc.

Proper knowledge and understanding of such factors provide a strong base for protecting and conserving the ecosystems.