
In general, the term '
evolution' can imply a drastic orgradual change from a very broad perspective. Life on earth, the universe,galaxies, as also the earth in general have evolved through millions of years.In this essay we consider only one aspect of
evolution emphasizing on
evolutionas a biological tool for change among species
and consider fossil record assupportive of both
evolution theories
and also the other theories contrary to
evolution.
Evolution is the central unifying concept, a theory thatsuccessfully connects biology, paleontology
and other branches of science.
Evolution is a gradual descent of organisms accompanied by changes that helpthe organisms to adjust
and adapt to the surroundings. 'Descent withmodifications' as Darwin contended implies changes in organisms in successivegenerations (Mayr, 1976). These changes are triggered by the derivation of newspecies
and there is a change in the properties of populations of organisms
andthese properties tend to transcend the lifetime of any single individual. Newerspecies are modified versions of older species.