Write short notes based upon the information known to you.
Evolution: Evolution refers to the gradual change which occurs in an organism over a long duration of time. It is a slow going process which results in the development of the organism. Life originated on earth about 3.5 billion years ago. It is believed that there might have been presence of simple elements on earth which may have given rise to simple organic and inorganic molecules. From these simple molecules, complex molecules like proteins, DNA etc. may have been formed. Other evolutionary changes may have resulted in the formation of simple cells and the result of the continuous evolution on earth is the several species of plants and animals which exist on earth. Today, the diversity on earth varies from unicellular Amoeba to a human being and from a unicellular algae like Chlorella to huge Banyan tree.