CONCEPT OF SPECIES It is already been stated that individual organisms which have many features in common and able to interbreed in natural conditions are encompassed by the term species. Species is the smallest basic unit of classification. Its proper characterization is, therefore, of vital importance for a 'Natural' scheme of classification. Identifying species on the basis of reproduction, John Ray (1693) considered all individuals produced by parents of the same types as members of the same species. Linnaeus and Some others distinguished species merely on the basis of structure. Morphological Concept of Species This is the most practical and widely used species concept to describe species since people began to classify organisms. Taxonomists use this concept mostly by default because they know most of the species on Earth only from their morphology. New species are usually named on the basis of morphological species concept; morphological descriptions are all that we need...
Charles Darwin gave the theory of Natural Selection that is applicable to both plants and animals. Darwin's theory of evolution Charles Robert Darwin ( 1809-1882 ) was a British naturalist who made significant discoveries of biology. He became the unpaid naturalist in 1831 and set out on a voyage when he was 22 years old. He developed the idea of organic evolution by natural selection on his five-year expedition around the world. When he returned to England, he didn't leave again and stayed at home. He conducted various experiments and formulated the hypothesis stating that evolution occurred due to natural selection. Darwin gave the theory of evolution called The Theory of Natural Selection in his book The Origin of Species. The Theory of Natural Selection in his book The Origin of Species. The Theory of Natural Selection suggests that the best adapted organisms are naturally selected to pass on their traits to the offsprings. Darwin's theory of evolution can be expl...