
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.