The Importance Of Water For Life On Earth Essay

1501 Words Sep 27th, 2016 7 Pages
Just as it is a difficult task to concisely define what constitutes life on Earth, it is equally difficult to construct a list of environmental requirements that represents the bare essentials for life. In general, astrobiologists are in agreement that life needs a liquid medium for transporting the molecules that are necessary for its existence. For life on Earth, this liquid medium is water. Many other liquids have been proposed as potential substitutes for water, such as ammonia (NH3), methane (CH4), or ethane (C2H6). However, as we will see, water is a versatile and somewhat unique molecule that is extremely compatible for life on Earth, and probably other planets.
As we begin our discussion on the importance of water for life, it is important to recognize that water is possibly the most abundant liquid in the universe. But does that necessarily make it the best candidate for life? Water is composed of two hydrogen atoms and a single oxygen atom; there are a total of two chemical bonds in the molecule. Each of the hydrogen atoms is bound to the oxygen by a covalent bond – a bond formed by the sharing of one or more electrons between two atoms. In the case of the oxygen-hydrogen covalent bond, the electrons are not shared equally between the two atoms. In fact, oxygen is a strongly electronegative atom and can be thought of as a bit of an “electron hog”. The oxygen will tug on electrons so that there will be a higher density of electrons around the oxygen as…

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