There are three theories that have been put forward to explain the mode of evolution i.e., origin of species. 1. Lamarck's Theory of Evolution: Lamarck proposed that the evolution of life forms had occurred by the use and disuse of organs. He gave the example of Giraffe, which initially did not have long necks. But, in order to reach the [...]
In this article we will discuss about:- 1. Concept of the Origin of Life 2. Approaches of the Origin of Life 3. Theories. Concept of the Origin of Life: The origin of life on earth is one of the most elusive and oldest problems of biology. For about one half of the long span of earth's history, the earth was [...]
In this article we will discuss about the origin of flight in birds. Birds constitute a very specialised group of vertebrates which have evolved from reptiles during Mesozoic era. The actual documentary records of the stages showing how such reptiles were transformed into birds are rare because of the non-availability of abundant avian fossils. Two fossil specimens of Archaeopteryx discovered [...]