EVOLUTION OF LIFE FORMS - A THEORY Video Lecture - Class 10

evolution of life-forms the theory of
special
it accounts for the existence of diverse
plants and animals it states that one
all living organisms species are types
where created as such to the diversity
was always the same since creation and
it will be the same in future also three
the earth is about four thousand years
old based on the observations Charles
Darwin concluded that existing living
forms share similarities to varying
degrees
not only among themselves but also with
life-forms that existed millions of
years ago
many such life-forms do not exist
anymore
there have been extinctions of different
life forms in the past and new life
forms arose at different periods of
times on earth there had been gradual
evolution of life-forms Darwin observed
small variations in almost all organisms
of a species that is differences in
characters between the individuals even
if they were closely related some
individuals had favorable variations
which ensured their success in this
struggle for existence whereas the other
like them obviously the fitted
individuals that possessed such
characters survived more and hence are
selected by nature he called it nature
selection and implied it as a mechanism
of evolution Alfred Wallace had also
come to similar conclusions all the
existing life forms shared similarities
and share common ancestors
however these ancestors were present at
different period in the history of Earth
therefore the geological history of
Earth closely correlated with the
biological history of Earth