The problem of population is the main cause of ecological environment damage. As the population grows up and economic develops, the increasing demand of resources is becoming more and more severe. Because of deforestation, unreasonably overgrazing dykes to reclaim land from a lake, marsh reclamation, excessive usage of land and water resources, which leads to the destruction of biological environment or even disappearance, the normal survival of the species is affected a lot. There is a large number of species which have not yet been detected by human beings. They have quietly become extinct, thus leading to destruction of biodiversity.

Land is the material basis of human survival. In the demand of the food sources of the survival of human beings, crops cultivated land accounts for 88%, 10% of grasslands and pastoral areas and 2% counted for marine. With the development and utilization of ocean, energy applied by sea food for human beings will increase. At present, the cultivated land of the world is about 1.37 x 109 hm2, which shows per capital is about 0.26 hm2. But due to the increase of the non-agricultural land land desertification, soil erosion, soil pollution and so on, it prompts the contradiction between population increase and reduce land resources becoming more and more sharp. What’s more, the pressure of increase in population on land is becoming bigger and bigger. According to the United Nations food and agriculture organization, nowadays, about 500 million people around the world are in a state of super land bearing capacity.

So the fresh water is going to run out. To discover and to make use of new sources are necessary within two aspects. One is to find fresh water resource which hasn ‘t been found or used. The other way is to thoroughly look for fresh water from where other than the fresh water resource it self. This is mainly asked to turn which is not fresh water purification into fresh water. Since sea water accounts a lot of the total water resources of the earth. The key means to turn them into the water we can drink is to purify and desalinate. Although it is not because that there is no water desalination plant in the world, why we still worry about water resources drying up? That is mainly due to the desalination technology which is not very mature and completed. Not to mention, the cost is very high as well. Ordinary people can not afford such high price. That explains why this technique is not popularized worldwide, but most concentrated in the developed countries. That is to say, if we want to fade in seawater batches, the most important is to rely on science technology to improve the efficiency of desalination, reduce the desalination cost and let ordinary people be able to use the desalinate water under a proper price.

Organisms of this ecosystem may generally be divided into three categories:

1. Producers, 2. Consumers, 3. Decomposers.

Producers mostly belong, to the category of plants that make their food by the inorganic substances by themselves in the presence of light.Consumers particularly include animals including human being, that de­pend for their food on other organism including plants, and the decomposers come in the category of bacteria and fungus etc. that decompose the organic substances present in dead plants and animals.

The system is useful to man. A perfect ecological balance cannot be expected in the wake of growing industrialisation as owing to this, pollution of environment becomes inevitable.The environment has “carrying capacity”, or the amount of pollution or damage an environment can sustain without further degradation.

By the misuse, abuse and uncontrolled use of resources both natural and otherwise have upset the equilibrium between human activity and nature.

1. Physical Environment. 2. Human Environment.

Physical Environment consists of all constituents of natural origin like physiography-, climate, vegetation, soil, water bodies, wild animals and minerals.

Human Environment consists of all elements having a human touch in their origin. Such elements include all manifestations of human activities.

Of course natural resources cannot be confined to the physical mani­festation of nature, it also includes the entire environmental scenario-the carrying capacity of nature, the extent up to which the nature can accommo­date.

Can we predict the ecological effects of pollution and climate change?

Governments and citizens around the world are increasingly aware of the consequences of atmospheric pollution and climate change. In large-scale experiments, plants and animals are exposed to carefully controlled atmospheres and different ecological conditions. Scientists use this information to understand how they respond to pollution levels, and make predictions about future climate change.

Can we fish the ocean without depleting its riches?

It is possible, but does depend on where we are in the world. In the Antarctic, the marine ecosystem is currently managed as a whole under an international agreement to conserve living resources. This makes it easier to understand marine communities and their interactions, as well as help monitor threatened species more closely.

Can we conserve a habitat and its biodiversity?

Yes. Ecology provides the essential basis for nature conservation. Maintaining a mosaic of habitats ensures the survival of a rich variety of species. For instance, heathland is a valued landscape that is fast disappearing throughout much of Western Europe, but studies have helped identify how to preserve its ecological characteristic.