After completion of this lesson, student must be able to:

  • Define evolution and interpret the process of evolution.
  • Enlist the evidences of organic evolution.
  • Explain the theories of evolution in brief.



Organic evolution is the process of gradual and orderly changes in organisms from one form to another. According to Modern concept of origin of life theory, the first living cell arose from simple elements. This note gives us the information about evolution.

Lamarck’s Theory of Evolution

According to Lamarck, the environment directly influences the modification of the organs in organisms. A constant use and disuse of organs leads to its modification in the form and less used structures reduced and ultimately gets lost. This note gives us the information about Theories of evolution and its use.

Darwin’s Theory or Darwinism

Darwinism is also known as Theory of Natural Selection. According to the Darwin, out of the vast number of individuals which compete for a place in the world, only those having advantageous variations survive and reproduce. This note provides us the information about Darwin's theory and mutation.

Organic Evolution

Traces and preserved remnants of dead animals and plants are called fossils. The study of fossils is called paleontology. An embryo is defined as a multicellular structure that is developed from the zygote and gives rise to new offspring generally present inside the female tissue or egg-membrane. This note gives us the information about various evidences of evolution.