Neo-Darwinism or Modern Concept or Synthetic Theory of Evolution:

 

 The detailed studies of Lamarckism, Darwinism and Mutation theory of evolution showed that no single theory is fully satisfactory. Neo-Darwinism is a modified version of theory of Natural Selection and is a sort of reconciliation between Darwin’s and de Vries theories.

Modern or synthetic theory of evolution was designated by Huxley (1942). It emphasises the importance of populations as the units of evolution and the central role of natural selection as the most important mechanism of evolution.

The scientists who contributed to the outcome of Neo-Darwinism were: J.S. Huxley, R.A. Fischer and J.B.S. Haldane of England; and S. Wright, Ford, H.J. Muller and T. Dobzhansky of America.

  Postulates of Neo-Darwinism:

1. Genetic Variability

2. Natural Selection and

3. Reproductive isolation

Darwinism or Darwin’s theory of evolution or Theory of natural selection:

 

Theory of evolution given by Robert Charles Darwin (1809-1882) is called a Darwin's theory of evolution or Darwinism or theory of natural selection.

Darwin

 

Historical Background:

 Charles Darwin Was born in Shrewsbury, England. He completed his high school

Evidences in favour of evolution

 

The evidences in favour of evolution can be obtained from

*Evidences from comparative morphology and anatomy

*Evidences from fossils or palaeontology

*Evidences from embryology

*Evidences from physiology and biochemistry

*Evidences from biogeography

Introduction to evolution

 The term evolution was given by Herbert Spencer. Evolution means gradual change from one form to another. It means to unroll or to unfold or to reveal the hidden potential.  The change in non-living things is called as inorganic evolution while change in living organisms is called organic evolution. Darwin defined evolution as “descent with modifications”. According to Dobzhansky “Nothing in biology makes sense except in the light of evolution”. 

Experimental Evidence for chemogeny (Miller- Urey Experiment):

 

Harold C. Urey; an astronomer in 1952 provided the first adequate recognition to oparin-Haldane’s view in university of Chicago. Urey asked his student Stanely L. Miller; a biochemist to replicate the primordial atmosphere as explained by Oparin – Haldane.

Miller

Urey

Origin of life: Modern theory Or Oparin-Haldane theory Or Biochemical theory:

The modern theory of origin of life was put forwarded by Haeckel in crude form. Thus, it required further exploration and experimentation. The exploration was done by Oparin and Haldane while its experimentation was done by Miller and Urey. 

AI (Alexander Ivanovich) Oparin(1894-1980) Was a Russian biochemist in 1923; he had given his view regarding the origin of life. He wrote book “Origin of life” in which he explained his view regarding origin of life. 

AI Oparin

Life and its origin:

    Life is unique and complex Organization of chemical molecules which can express itself chemically. How life originated on earth is still not having suitable answer.      Different biologists have proposed different theories for the origin of life. The major theories for the origin of life are:

*Theory of special creation

*Theory of spontaneous generation or Abiogenesis

* Theory of biogenesis

* The cosmozoic theory or theory of Panspermia

* The catastrophic theory

* Modern theory or Biochemical theory or Oparin- Haldane theory

Human evolution

^{Systemic position of Human}

^{Kingdom:                   Animalia}

^{Phylum:                      Chordata}

^{Sub-phylum:               Vertebrata}

^{Group:                         Craniata}

^{Division:                     Gnathostomata}

^{Superclass:                  Tetrapoda}

^{Class:                           Mammalia}

^{Order:                           Primate}

^{Sub-order:                   Anthropoidea}

^{Infra order:-             Catarrhini}

^{Super family:-          Hominoidea}

^{Family:                        Hominidae}

^{Genus:                         Homo}

^{Species:                       sapiens}

^{The wonder about the origin of human, from where human came to this earth remain unsolved for thousands of years. Huxley (1863) in his book “Man’s place in nature” established a close relation among monkeys, apes and man.}

Theory of Evolution: Lamarckism

^{Theory of inheritance of acquired characters or Lamarck’s theory of evolution}

^{The theory of evolution given by French   biologist Jean Baptist de Lamarck (1744 – 1829) is called as Lamarckism.}

Lamarck

^{Introduction to Lamarck}    

           

^{—    Jean Baptist de Lamarck was a French naturalist born in 01 August 1744 AD in Bazentin, France and died in 18 December 1829 in Paris, France. He was soldier, biologist and academician.}

^{—    He was first biologist to give the formal theory of evolution.}

^{—    In 1809 AD, He published a book entitled    “ Philosophique zoologique”, Zoological philosophy in English and explained his view on evolution.}