The Evolution of Improved Fitnes6

The Evolution of Improved Fitnes6 - specific sequence of...

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The Evolution of Improved Fitness 1.1.2 Information theory Several formal arguments have been put forward to the effect that random mutations cannot increase the information content of a system. Since the information content of the human genome is vastly larger than that of bacteria, if mutation cannot play a role in this increase then the foundation of evolution by mutation and natural selection would seem to be in question. 1.1.3 Statistical argument A final argument put forward by creationists against the role of random mutation in biological origins is a statistical calculation supposedly proving the impossibility of an evolutionary origin of proteins. A protein is large biological molecule constructed of smaller subunits, known as amino acids, which become linked together in a linear chain and then folded into a precise three- dimensional structure. There are twenty different kinds of amino acids in proteins, and the
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Unformatted text preview: specific sequence of these amino acids determines the final shape and properties of a given protein. A typical protein is composed of a hundred or more amino acids in a strictly defined order. The creationists ask: what is the probability that the correct sequence of amino acids of a specific protein -- for example, the 141 amino acids of the human oxygen-carrying protein called globin -- could have been selected by chance? The total number of possible 141-long amino acid sequences is 20 141 , a number so incomprehensibly huge that the statistical probability of the actual globin sequence ever appearing from a random assortment of amino acids is negligibly small. In a picturesque simile, the creationists are fond of comparing the probability of correctly assembling a protein sequence by this random selection model to the likelihood that a tornado blowing through a junkyard could assemble a 747 airliner....
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This note was uploaded on 11/14/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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