Phylogenetic
Approach -
The
post
Darwirian
biologists
thought
in
terms
of
evolutionary
affinities
between
organisms,
In
the
19th
century
the
concept
of
a
natural
system
accordingly
changed
if
pnylogenetic
ones.
However, this approach needs a sound knowledge of fossil records of organisms. We would like to refer here again to Protista. A German, Ernst H. Haeckel separated the unicellular organisms from plants and animals, placing them under a third kingdom, Protista. The fungi, protozoa, bacteria and algae were included in this kingdom.
A
modem
system
of
this
type
is
devised
by
R.H.
Whittaker
(1969).
We
have
already
referred
to
this
five
kingdom
system
of
the
living
world.
The
microorganisms
have
been
included
in
the
kingdoms
Monera,
Protista
and
Fungi
in
this
system.
