Tuesday, March 31, 2009

How the Living Organisms interact with the Environment

Living organisms and the physical environment have a close relationship. They interact with each other. The biosphere is the parts of Earth inhabited by living organisms. The biosphere consists of specific geographical areas known as biomes. A biome is a collection of different types of ecosystems. The ecosystems include grasslands, rain forests, streams, lakes, sea, deserts etc., with various types of organisms starting from bacteria, fungi, algae, and various other types of plants and animals. There are millions of known species of organisms and there are many millions to be discovered. Each organism lives in a specialized regional environment within the ecosystem known as the habitat. An organism can live in a specific habitat because it is adapted to live in that habitat. Deep-sea vent, bottom of sea, arctic rivers, and river banks, etc. are examples of habitat.

Organisms living in a specific environment interact with the environment and also with themselves in very different ways. There are big trees growing along the bank of the stream. Since the trees are very big, they make half of the stream a shady area, and this may make the temperature of the water a bit lower than that in the middle region. It is because the water at the bank side is not directly heated by the sun. Similarly, there are many algae floating in the water freely, and this may reduce the penetration of sunlight. So the light intensity under the water may be decreased. All the organisms living in an environment along with that physical environment form an ecosystem. The organisms living in a fresh water pond, along with the pond, form an aquatic ecosystem. All organisms on land along with their environment form the terrestrial ecosystem.

The energy flow in an ecosystem obeys the laws of thermodynamics. It is an open system. An open System allows the free flow or exchange of energy and matter such as water, carbon dioxide, nitrogen, food materials, and even the movement of organisms from one ecosystem to another. There are producers, consumers, and decomposers in ecosystems. The producers are the photosynthetic organisms or the autotrophs. The producers of the ecosystem take energy from sunlight and convert it into chemical energy. This energy is passed on to consumers and then to decomposers, which cycles back the materials to the environment. But the energy flows only in one direction and is not cycled back. Herbivorous animals consume the organic food synthesized by the producers, which form the primary consumers.

These herbivores form the food of carnivores, which are the secondary consumers. And finally the decomposers act on the dead remains of all these organisms including the producers. decompose the organic materials into inorganic materials, and thus cycle back the materials to the environment. This forms the food chain in the ecosystem. In each step of the food chain energy is also transferred. In each step a portion of the energy is lost in the form of heat. Thus, heat is flowing in one direction and is not cycled back. The energy enters the ecosystem from the sun through producers and leaves the ecosystem in all steps of the food chain in the form of metabolic heat.

The materials in the form of nutrients required for life are cycled between organisms and the environment. The materials are absorbed by the producers for synthesizing the nutrients and are cycled among the consumers and finally returned to the environment by the activity of saprophytes and other decomposers such as fungi and bacteria. Considering the flow of energy and nutrients in the ecosystem and in the biosphere, it can be considered a single living organism.

Tags: Bio Technology, Bio Genetics , Life Forms, organisms

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