OCCURENCE OF
EVOLUTION
THEORY
-is an idea about how something in nature works tha
has gone through rigorous testing through
observations and experiments designed to prove the
idea right or wrong.
THEORY OF NEED
States that organisms change in
response to their environment. Their
ability to survive helped them develop
characteristics necessary for them to
adapt in a given environment.
THEORY OF USE AND DISUSE
According to Lamarck,
organs not in use will
disappear while
organs in use will develop.
THEORY OF ACQUIRED
CHARACTERISTICS
Acquired characteristics were
believed to be inherited by their
offspring and propagated
by the next generation of giraffes.
According to Darwin, giraffe species
originally had varying neck lengths
but natural selection favored the
survival of giraffes with longer necks
that could feed on taller trees that
were available.
Giraffes with short necks were
eliminated due to lack of
accessible food supply
ALFRED RUSSEL
WALLACE
(1 8 2 3 -1 9 1 3 )
Natural selection is
the process through
which species adapt to
their environments. It