Ø populations, that are reproductively isolated from such other

Ø Article Name

Ø Biological
Species Concept

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

v Introduction

Biological
Species concept is mostly widely. Different scientists explain different
species according to their point of views that are described in a step wise
manner.

v Definitions

Different
definitions according to different scientists are given below:

According to
Dobzansky in 1937,

”Specie is
a group of interbreeding natural populations, that are reproductively isolated
from such other group”

According to
Mayer in 1942 who firstly developed the biological specie concept,

”Group of actually or
potentially interbreeding natural population which are reproductively isolated
from such other groups, is called specie” This
concept provides a useful tool to understand the many animal and plant species

 According to Grant in 1957,

”Specie is
a community of cross-fertilizing individuals that are linked together by bonds
of mating and reproductively isolated from each other by barriers of mating”

Weed is
reproductively isolated from such other groups. Identification of Biological
specie is based upon two main points i.e.

1)  
Interbreeding among populations of the same species

2)  
The reproductive isolation between members of different specie

According to
Valentine and love in 1958,

Species could
defined on the basis of gene exchange

”When two
populations have ability to exchanging their gene under the natural or
artificial condition, then both of these two populations are called conspecific
means member of the same specie”

While,

”When two
populations that don’t have ability to gene exchanging under natural or artificial
conditions, they will be said as specifically distinct”

 

v Some examples of biological species:

1)   
Now a days, Hamadryas baboons and olive baboons are considered two
different species due to their genetics, but they can interbreed occasionally.
So, according to the biological species concept, we can consider them one
species, because they come into contact with each other in nature and they can
interbreed.

2)   
Lions and tigers can reproduce and some of their
offspring are fertile themselves. On the one hand, we can say that both of these
are one species because they can potentially interbreed in nature under very
extreme or unlikely circumstances. But as we know that, biological species
concept is not without its flaws. Sometimes, it is very useful and sometimes
it’s not as suitable according to other ideas.

v Limitations

A
biological species concept has important impacts on the evolutionary theory. It
is limited when it is applied to specie in nature.

For
example,

1)   
Nobody can evaluate  the reproductive isolation of morphologically
similar fossils

2)   
This concept can only be applied to
those populations that are overlapped geographically

3)   
Moreover, the criterion of
reproductive isolation cannot be evaluated in many species like, Bacteria,
viruses reproduce completely asexually and are arranged to species which is
mainly based on structural and biochemical characteristics