1. It is normally an open system with a continuous, but variable influx and loss of materials and energy.

2. An ecosystem is an overall integration of the whole mosaic of interacting organisms and their environment.

3. It is a basic, functional unit with no limits of boundaries.

4. It consists of biotic and abiotic components interacting with each other.

5. Its functional unit is capable of energy transformation, circulation and accumulation.

6. An ecosystem is the smallest unit of biosphere.

7. Different types of ecosystem are present in different areas.

Rainforests are thought to be the oldest ecosystem on earth, accounting for the greatest diversity of plants and animals.

Tropical rainforests exist in three major global areas: Central & South America, Africa and Indo-Malaysia.They are aptly referred to as rainforests, averaging between 125 to 660 cm of rainfall annually.

Tropical rainforests are generally found near the Equator, allowing the most direct sunlight of any habitat; consequently there is no cold season.Temperatures average between 20ºC and 34ºC. The combination of warmth and rainfall creates a very humid environment.The warm air retains the water vapour, but as the air rises and cools, clouds form, producing more rain.

It is calculated that there are more than 50 million different species of invertebrates in the rainforest, by far the largest family found. Many have not yet been identified and even new mammals are still being discovered, such as the tiny maues marmoset monkey, found only in a very small pocket of the Amazon rainforest.

Some plants and animals have developed a close association of mutual benefit (symbiosis). For instance, The Azteca ant finds its nourishment, water and shelter on the acacia tree, and in turn it protects the tree from potential predators by fiercely attacking them.

Seed dispersal by birds and mammals plays a major role in the germination of new trees. The birds and mammals eat the seeds found in fruits, then travel great distances away from