Biology Today — January 2018

EVOLUTION-II

Analysis of various PMTs from 2013-2017

2013

2014

2015

2016

2017

AIPMT/NEET

2

2

1

4

AIIMS

1

2

2

AMU

4

1

Kerala

1

2

K-CET

1

2

2

J & K

1

Class XII

• The various evidences of evolution ascertain that simple living organisms gradually
  modified into complex forms. This idea of organic evolution dates back to 322
  B.C. when Aristotle believed in a ladder-like gradation in nature and suggested
  that there had been a gradual transition from the simple and imperfect to the
  complex and perfect. Similarly, Buffon (1707-1788 A.D) the great French naturalist
  was the first to propose the direct modifying influence of the environment. He is
  therefore, also considered as the “Father of Evolutionary Concept”.


• However, the first person to put forth an elaborate theory of organic evolution and
  the origin of species by adaptations to environments was also a French naturalist,
  Jean-Baptiste de Lamarck. Many more theories have been proposed later to explain
  the concepts of organic evolution.


• Some of the important theories to be discussed here are:

Lamarck’s theory

Darwin’s theory

Hugo de Vries’ theory

Synthetic theory of evolution

Theories of Evolution

LAMARCK’S THEORY

• Lamarck published his theory of evolution in ‘Philosophie Zoologique’ in 1809.
  It is popularly known as ‘the inheritance of acquired characters in organisms’. It
  can be defined as “the changes in structure or function of any organ acquired
  during the life time of an individual in response to changes in the surrounding
  environment are inherited by its offspring and keep on adding up over a period
  of time”.


• Thus, Lamarck stressed on adaptations as means of evolutionary modification.