Презентации для урока агглийского языка по теме Биосфера

The biosphere

The biosphere is the layer of the Earth in which all life exists. The term biosphere was coined in 1875 by the geologist, Eduard Suess, but it was Vladimir Vernadsky who recognised its ecological importance in 1929. He believed that all living organisms together with their environments make up the biosphere. These environments include the air (the atmosphere), land (the geosphere), rocks (the lithosphere) and water (the hydrosphere). The exact thickness of the biosphere on Earth is difficult to calculate, but most scientists would agree that it is from about 5000 metres above sea level to around 9000 metres below sea level. Thus, there is a 14-kilometre zone within which life exists.

The biosphere is important because it is all of life. Without the biosphere, Earth would be a lifeless planet like all the others in our solar system. Also, the biosphere could not exist without water. Water is essential for all living organisms on Earth and has played a very important role in the evolution of life on our planet. Life on Earth began approximately 3.5 billion years ago in the oceans. At that time, Earth was very different from what it is today.

The earliest forms of life were very simple organisms similar to modern bacteria. Over millions of years, more complex organisms evolved and in time, many different forms of life began to inhabit the land, the sky and the oceans. They all depended on each other to survive. The biosphere is like a ladder. This ladder is known as the food chain, and all life depends on the first step of the ladder which is made up of plants. Animals eat the plants; bigger animals eat the smaller animals, and so on. In this way, all organisms are closely connected to their environment.

The biosphere is what keeps us alive. It gives us our food, water and the air that we breathe. Everything we need in order to grow and survive comes directly from the biosphere, so it is important to protect it; however, humans have not always done that. Humans have had a huge impact on the biosphere. Sometimes this has been good, but at other times it has been very destructive. The growing human population on Earth means there is less room for other species and by destroying their habitats we have made many types of plants and animals extinct.

As scientists learn more about our world, they can help us to understand the biosphere, how it evolved, and even try to predict how the biosphere will respond to global change and human activities. Scientists are very concerned about the future, particularly how people will affect the environment in harmful ways. It is very important to try to prevent any permanent damage, or we will destroy ourselves.

Vladimir Vernadsky

Vladimir Ivanovich Vernadsky was a Russian scientist who was born on 12th March, 1863 in St Petersburg. His most important contributions to science were the development of the ideas of the biosphere (from the Greek word bios meaning life) and the noosphere (from the Greek word noos meaning mind).

He graduated from the Physics and Mathematics Department of St Petersburg University in 1885. From 1890 to 1911 he taught mineralogy and crystallography at the University of Moscow. In 1912 he was made a full member of the Russian Academy of Sciences where he was actively involved for 33 years, until his death in Moscow on 6th January, 1945.

Through his work in mineralogy, Vernadsky became interested in the distribution of chemical elements in the Earth's crust, hydrosphere and atmosphere - the field known as geochemistry. Vernadsky published many papers on the geochemistry of various elements, including the geochemistry of radioactive compounds.

Vernadsky was one of the first scientists to suggest the possibility of using radioactive elements as sources of energy, and he organised a special commission to look for uranium ores in Russia. In 1916, the first uranium deposits were discovered. But Vernadsky was aware of the danger of putting atomic energy into the hands of man. He said that scientists carried the huge responsibility of making sure their discoveries did not lead to destruction.

However, Vernadsky is probably best known for his development of the idea of the biosphere of the Earth and his ideas on the evolution of the biosphere into the noosphere.

He defined the boundaries of the biosphere by showing that the biosphere includes all the hydrosphere, part of the troposphere - the lowest layer of the atmosphere where most weather changes take place - and the upper part of the Earth's crust down to a depth of two or three kilometres, in short, everywhere that life exists. For Vernadsky, the biosphere had existed since the very beginning of the Earth's history and it was constantly evolving. Our present living world is the product of a long and complex evolution of the biosphere.

Vernadsky believed that the technological activities of mankind were a stage in this evolution. He believed that human reason and combined scientific efforts could overcome the negative results of technology and could lead to a safe future for everyone. This positive evolutionary stage of the biosphere of the Earth is for him the noosphere, the sphere of reason.

In his paper, Several Words on the Noosphere (1944, the last paper he published before his death), Vernadsky outlined the conditions that were required for the creation of the noosphere: equality for all people and an end to wars, poverty and hunger. Today, Vernadsky's vision of the world is more important than ever before.