Reproductive system - an overview | ScienceDirect Topics
The principle events in the evolution of the earth essays The Principle Events in the Evolution of the Earth's Atmosphere The literal translation of the word atmosphere is "sphere of vapors". The Earth's atmosphere is a protective sphere of vapors, or air that surrounds the Earth and provides it with a layer of insulation from the harmful rays of the sun. It is a vital part of the Earth, and has changed dramatically since the beginning of time. The earth's atmosphere has gradually changed since the Earth's birth approximately 4.6 million years ago. In the beginning, the Earth's composition was very different that how it exists today. A long time ago the Earth's atmosphere was very similar to today's Venus and Mar's atmosphere. It had about 95% carbon dioxide, 2-3% nitrogen, and very little, less than 1% oxygen. Today the Earth contains 79% nitrogen, 21% oxygen, and 3% water vapor. It is evident that there were many events that happened over billions of years that have contributed to this change in the Earth's atmosphere. The Earth had developed so drastically because of the tremendous dust and gas cloud within the Milky Way galaxy. The Earth grew larger as huge meteorites hit it, and the surface was covered with dust. Volcanoes began to form and emitted lava, ash, and most importantly gases. Carbon dioxide, water vapor, and nitrogen were Indian Stars: August 2008 - iconsofindia.blogspot into the atmosphere from the volcanoes. This process is called outgassing, and took place within the first million years or so of the Earth's formation. Then, about 4 billion years ago, the planet cooled, and the outgassed water vapors condensed into clouds. It rained and produced the oceans, and even enough to Fast Essay Writing Aid for Students - paper writing website 95% of the Earth. In addition, because it rained, there was less carbon dioxide in the atmosphere. The carbon dioxide was lost over billion of years, as the ocean formed there was a chemical reaction in which carbon dioxide and water formed carbonic acid. It is shown in the equation CO2 + H2O = H2CO3. The carbonic acid dissol.