marți, 15 aprilie 2008


- The Life view of Science

Science has a theory of how life began and changed on earth called the Theory of Evolution. The general framework of this theory is accepted by all who have looked carefully and open mindedly at the evidence. Some specific details of the theory continue to change as more evidence becomes available, just like for most of the other major theories of science. According to the theory, the oceans of the early earth were filled with many combinations of atoms, called molecules, including those of the organic (carbon-oxygen) variety. Experiments have shown that electrical discharges (such as lightning) through water containing organic molecules can form amino acids, the basic building blocks of life as we know it. It has been observed through the geologic record that by 3.5 billion years ago the earth's oceans contained bacteria and algae, but it was not until 570 million years ago that evidence of animals with shells and flying insects is found. The key to this appearance of life that can change and reproduce is the DNA molecule. Endless varieties of amino acid combinations in the oceans apparently produced this DNA type of combination, where the main priority is the perpetuation of itself, this amino acid pattern. Slight errors in replication along with the principle of natural selection account for the variety and persistence we see in life. Natural selection was finally proposed as the mechanism for the evolution of life in a theory by Charles Darwin about 140 years ago. This is where only those organisms having DNA-produced characteristics that enable them to live long enough to have offspring will pass along those same life-sustaining characteristics. Thus certain DNA combinations are naturally selected by the environment to be passed on, because the DNA combinations are what determine the characteristics of the resulting organism. The evidence for the theory of evolution is overwhelming. Embryology is one of several fields of study that provide the evidence. Amazingly, the development of the human embryo roughly follows the order of archeological record: the human fetus actually has a tail in early stages. Following is an overview of the deductions by Science indicating about how many years ago certain events first occurred: 13B Big Bang, 5B Solar System, 3.5B Bacteria/Algae, 570M Free Oxygen/ Crustaceans/ Flying Insects, 400M Fish/Amphibians, 225M Reptiles, 80M Dinosaurs Extinct, 70M Mammals, 35M Monkeys, 8M Australopithecus, 3M Walking Man, 2.5M Division of Labor/ Stone-age Tools, 2M Human, 500K Fire Use, 250K Homo Sapiens, 50K Counting, 40K Bow/Arrow, 30K Paintings, 14K Fire Starting/ Domestic Dog, 12K Metal Use, 11K Agriculture, 9K Pottery, 8K Beer, 7K Cloth, 6K Writing/Music/Egypt/Tempering, 5.5K Wheel/Bronze. The effects of this 3.5 billion years of evolution that has resulted in the DNA that has formed each and every one of us can not be over estimated. The main question is just how much of what we see and feel, the emotions and priorities we have, and the interpretations we make are influenced (or even determined!) by our biological background.

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