How Nature Works in Harmony

Class 08 Science

The living beings are termed as the biotic components and non-living things as the abiotic components of a habitat.

Every organism needs specific conditions to survive. Different habitats offer different living conditions.

A pond provides food, oxygen, shelter, and space to grow - conditions essential for survival of organisms. Fish obtain their biotic needs, such as food, from small plants and animals, and abiotic needs, such as oxygen, from water. Other living beings also inhabit the pond, such as frogs, fresh turtles, snakes, dragonflies, mosquitos, snails, and ducks, along with plants like algae, diatoms, duckweeds, and lotus. They all interact with the other living beings and non-living things present in the places where they grow and thrive.

Habitat

Each habitat has its own biotic components and physical conditions - air, sunlight, water, temperature, and soil. Different organisms living in the same habitat may use the resources in different ways. A forest might be warm during the day and cool at night. A snake that comes out at night and a rodent active during the day both live in the same habitat, but they face different conditions. This is how living organisms coexist in harmony in the same habitat.

Different group of organisms live together in a habitat. A community comprises different populations sharing the same habitat. The biotic components of a habitat, such as the plants, animals, and microorganisms together form the community. These organisms interact and depend on one another for survival.

Different Types of Interactions

Plants and animals need air, water, soil, and sunlight to grow. Living organisms, or the biotic community, depend on non-living things, that is abiotic components for their survival. Plants and animals also depend on each other for nutrition, respiration, and reproduction. These are interactions among the biotic components. Both types of interactions - among biotic components, and between biotic and abiotic components - are important for survival in any habitat.

The biotic components (plants, animals, and microorganisms) and the abiotic components (air, water, soil, sunlight, and temperature) in a habitat interact with each other to form an ecosystem. Organisms in an ecosystem interact with abiotic components for food, shelter, and protection in an ecosystem. Different communities of living organisms interact with abiotic components in an ecosystems.

There are two main types of ecosystems in nature. Aquatic ecosystems include ponds, rivers, and lakes while terrestrial ecosystems include forests, farms or even large trees like banyan, mango, or pilkhan.

Plants make their own food by the process of photosynthesis. Thus, they are called producers or autotrophs (auto = self + troph = food). Organisms that cannot produce their own food and depend on other organisms for their food are called consumers or heterotrophs (hetero = other + troph = food).

Organisms that eat only plants are called herbivores, such as deer and hare. Those that eat only animals are carnivores, such as leopard. Organisms that eat both plants and animals are omnivores, such as crows, foxes, and mice.

Food Chain

The interactions between biotic components based on feeding relationships can be represented in the form of a linear chain. A food chain is a simple sequence showing ‘who eats whom’ in an ecosystem. For example,

Grass → Grasshopper → Frog → Snake → Eagle

Each organism in a food chain has a specific position, called a trophic level.

• Producers (like green plants) are at the first trophic level.
• Herbivores (like hares and deer) are at the second level.
• Small carnivores (like frogs) are at the third level.
• Large carnivores (like tigers or vultures) occupy the next level.

In an ecosystem, the food chains are interlinked with each other to form a network, called a food web.

Decomposition

Microorganisms like fungi and bacteria break down complex substances in dead plants and animals into simpler ones. This process returns important nutrients to the soil. This process is called decomposition and the organisms carrying out the process are called decomposers or saprotrophs (sapro = rotten + trophs = food). Plants grow in soil and many of the nutrients in soil come from the decomposition process. Thus, decomposers play an important role in recycling nutrients.