Unlike physics and astronomy, in which unbiased observation directly contradicted religious teachings, for a long time progress in biology did not challenge old wisdom. Throughout the 16th and 17th centuries biologists classified all known plants and animals into taxonomical groups, and were, therefore, well aware of the commonalities living organisms shared. Yet, the belief that all living organisms had been created in their current form was so well rooted that no serious alternative existed before 1859. This was the year that Charles Darwin shocked his contemporaries by implying that humans and animals shared a common ancestor.
In 1831, Charles Darwin (1809–1882) joined as a naturalist the survey ship HMS Beagle for an expedition around the world. When he returned home in 1836 with over 2000 pages of notes and thousands of skins, bones and fossils, his work had just begun. It took over 20 years before he finally formalized his findings and observations into a consistent theory, which he published in his book On the Origin of Species by Means of Natural Selection.
Natural selection theory suggests that adaptation to the environment, through the survival of the fittest, is the main (though not the only) mechanism of evolution. Random variations continuously occur in species, which are constantly under struggle for resources. When “the surviving one of ten thousand trials” gives an organism an advantage in its environment, it would pass on this favorable change to its offspring. Accumulation of such variations within a population, particularly when major environmental changes occur, could eventually lead to the creation of new species.
Both the super bug and the bird flu are contemporary evidence that evolution processes are happening here and now.
2008-03-14 @ 11:27