ENDANGERED ANIMALS

An endangered species is a population of organisms which is facing a high risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters. The International Union for Conservation of Nature(IUCN) has calculated the percentage of endangered species.

 Many animals are in danger of extinction, like the orangutan and the chimpanzee. 
In Africa people hunt elephants and rhinoceroses for the tusks. In the seas many types of fish as 
well as many types of whales are close to extinction. In the air, eagles and storks are at risk. 
Organisations like the World Wild Fund for Nature (WWF) help to protect these animals.

Species examples

Examples of critically endangered animals:

§                    African Forest Elephant

§                    African Penguin

§                    African Wild Dog

§                    Agile Gibbon

§                    Amami Rabbit

§                    Asian Elephant

§                    Asiatic Lion

§                    Bengal Tiger

§                    Blue Whale

§                    Bonobo

§                    Borneo Elephant

§                    Bornean Orangutan

§                    Bornean white-bearded gibbon

§                    Central Chimpanzee

§                    Common Chimpanzee

§                    Cuban Solenodon

§                    Dhole

§                    Dingiso

§                    Eastern Chimpanzee

§                    Eastern Gorilla

§                    Eastern Lowland Gorilla

§                    Ethiopian Wolf

§                    Florida Panther

§                    Giant Panda

§                    Hispaniolan Hutia

§                    Hispaniolan Solenodon

§                    Indian Elephant

§                    Kloss's Gibbon

§                    Lar Gibbon

§                    Malagasy Giant Rat

§                    Müller's Bornean Gibbon

§                    Nigeria-Cameroon Chimpanzee

§                    Pileated Gibbon

§                    Proboscis Monkey

§                    Siamang

§                    Silvery Gibbon

§                    Southern White-cheeked Gibbon

§                    Sri Lankan Elephant

§                    Sumatran Lar Gibbon

§                    Takahē

§                    Volcano Rabbit

§                    Western Chimpanzee

§                    Western Hoolock Gibbon

§                    Yellow-cheeked Gibbon

GLOBAL WARMING:

Greenhouse effect

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.

Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in turn re-radiate much of the energy to the surface and lower atmosphere. The mechanism is named after the effect of solar radiation passing through glass and warming a greenhouse, but the way it retains heat is fundamentally different as a greenhouse works by reducing airflow, isolating the warm air inside the structure so that heat is not lost by convection.

Rainforest

Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm (68-78 inches). The monsoon trough, alternatively known as the intertropical convergence zone, plays a significant role in creating the climatic conditions necessary for the Earth's tropical rainforests.

Around 40% to 75% of all biotic species are indigenous to the rainforests.^] It has been estimated that there may be many millions of species of plants, insects and microorganisms still undiscovered in tropical rainforests. Tropical rainforests have been called the "jewels of the Earth" and the "world's largest pharmacy", because over one quarter of natural medicines have been discovered there. Rainforests are also responsible for 28% of the world's oxygen turnover, sometimes misnamed oxygen production, processing it through photosynthesis from carbon dioxide and consuming it through respiration.

The undergrowth in a rainforest is restricted in many areas by the poor penetration of sunlight to ground level. This makes it easy to walk through undisturbed, mature rainforest. If the leaf canopy is destroyed or thinned, the ground beneath is soon colonized by a dense, tangled growth of vines, shrubs and small trees, called a jungle. There are two types of rainforest, tropical rainforest and temperate rainforest.

Preventing forest fires:

• Only light fires in places where fires are permited. Put on your fire completely before you leave.
• Do not leave bottles on the grass. Bottles act as magnifying glasses. They can cause fire.
• Do not burn rubbish or twings in a wood or forest.
• If you smell burning or see smoke in a forest, notify the forest rangers or the firefighters immediately.

Ozone layer

The ozone layer is a layer in Earth's atmosphere containing relatively high concentrations of ozone (O₃). However, "relatively high," in the case of ozone, is still very small with regard to ordinary oxygen, and is less than ten parts per million, with the average ozone concentration in Earth's atmosphere being only about 0.6 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere from approximately 20 to 30 kilometres (12 to 19 mi) above Earth, though the thickness varies seasonally and geographically.

The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958 Dobson established a worldwide network of ozone monitoring stations, which continue to operate to this day. The "Dobson unit", a convenient measure of the columnar density of ozone overhead, is named in his honor.

Acid rain

Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals, and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxides, which react with the water molecules in the atmosphere to produce acids. Governments have made efforts since the 1970s to reduce the release of sulfur dioxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightningstrikes and sulfur dioxide is produced by volcanic eruptions. The chemicals in acid rain can cause paint to peel,corrosion of steel structures such as bridges, and erosion of stone statues.

ENVIRONMENTAL RISKS

NOISE POLLUTION:
How can noise harm you?

Noise-induced hearing loss may occur through occupational noise exposure or through
exposurre to moderm urban noise. It is a gradual process progressing over a period of years, 
withyou any external signs at the outset. It causes comulative and finally irreversible damage in 
the middle and inner ear. After exposing the ear to sound above 110 dB or so for a few 
minutes, audiometry will show a temporary hearing loss, and after sufficient exposure time this 
becomes permanent.

WATER POLLUTION:

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds.

Water pollution affects plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and populations, but also to the natural biological communities.Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels (international down to individual aquifers and wells).

Water is typically referred to as polluted when it is impaired by anthropogenic contaminants and either does not support a human use, such as drinking water, and/or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major changes in water quality and the ecological status of water.

AIR POLLUTION 

• Acid rain :Acid rain comes from industrial countries. But the wind carries it and a lot of it falls on their neighbours. 
• The greenhouse effect: industrial countries also cause the 'greenhouse effect'. This gas works like the glass walls of a greenhouse. It lets in the sun, but it doesn't let out the heat. So the Earth gets hotter and hotter. 
• Pesticides The pesticide chemicals get into the 'food chain'. Insects eat the pesticide. Birds eat the insects. Big birds eat little birds. At the top of the food chain you find birds like the Peregrine Falcon. Fifty years ago they were common. But more and more of the pesticide DDT got into their blood. Their eggs became weak, and broke. Now the Peregrine Falcon is quite rare.

THE ENVIRONMENT

The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species. The concept of the natural environment can be distinguished by components:

All living criaturas and the characteristics of the area where they live form the enviroment.
Every living creature lives in a specific place. People have adapted to live anywhere.

ENVIROMENTAL PROBLEMS

• The acumulation on the ground, in the air, and in the water of harmful substances causes pollution. These substances harm living creatures.
•  Deforestation is the disappearance of forest. Cutting down many trees, pollution and fires causes trees disappear.
•  Desertification is the transformation of some landscapes into desert areas. The soil is very dry and very poor.
•  Excessive hunting, fires, and other actions can cause the extinction, or disappearence, of living creatures.

Many enviromental problems are connected. For example, deforestation leads desertification and the extinction of living creatures.

SOLUTIONS

• Reduce pollution. We can useautomatic fuels that do not pollut as much. 
•  Avoid cutting down trees wild for wood. We can grow trees and cut them down to get wood.
• Fordib funting animals that are in danger of extinction. Can stop selling the products we get from these animals, like ivory.
• Protect specific areas that are very important because of their natural values. We can do this by creating protected natural areas.

Everyone in our society has to cooperate.

ECOSYSTEMS

An ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system. These components are regarded as linked together through nutrient cycles and energy flows. As ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can come in any size but usually encompass specific, limited spaces (although it is sometimes said that the entire planet is an ecosystem).

The elements in an ecosystemAn ecosystem is made up of a specific area and the living creatures that live there.

• .The biocenosis is the group of living elements in an ecosystems (animals, plants, algea and fungi) 
• e biotope is thegroup of non-living elements in an ecosystem ( soil, air, water, temperature, wind, humidi, and so on.)

Relationships between living creatures in an Ecosystem

All living creatures in an ecosystem interrelate to eat,protect themselves, reproduce, etc. Food relationships are very important in an ecosystem because living creatures eat one another. They form food chains.
Any change in an ecosystem affects all the luving creatures because they are interrelated.

Relationships between living creatures and their habitat in Ecosystems

Living creeatures live in a different places on the Earth. Any change in the habitataffects the living crearures in the ecosystem.
The living crearures in an ecosystem also influence their habitat.

Change in Ecosystems

The changes may be natural or they may be a result of human actions. They tend to become more complicated with time. Many different animals and plants appear over the years. The ecosystems become more stable.

Ecosystem stability

An ecosystem is stable when its living creatures, soil, temperature,etc. can change without the risk of the ecosystem disappearing.

Ecosystems develop

An ecosystem can develop gradually in a place where previously there was no life. An ecosystem of one kind can change into another kind.

1.  Small plants, like moss, appear in stony area where there is no vegetation.
2. Several types of grass and animals, like worms, beetles, mice and birds star to appear. The result is pasture.
3. Thicket is a dense growth of bushes and shrubs. The soil becomes richer. It supports more living catures.
4. Forest. Has grasses, bushes, trees and animals.

An ecosystem takes many years to develop. The four steps above could take more than 200 years.

People change ecosystems

• Cutting down trees for wood to make paper.
• Building hydroelectric power plants to generate electricity from water.
• Putting up overhead electrical cables to distribute electricity.
• Discharging contaminants into the atmosphere rivers and the sea.

Protecting Nature:

Reforestation, planting trees, banning hunting certain animals. All there actions protect nature.

-Some areas are designated nature reserves.