Question

CAN any one answer that how did life start on earth and how did th first whaterver form of live evolve or upgrade in to such suphosticated and variable life forms in brief

Answer 1

There are many theories given on the origin of life on earth but the most popular and accepted theory is the 'theory of abiogenesis'. According this theory, life originated on earth about 3.5 billion years ago. During these early period of earth's origin, the atmosphere was reducing with high voltage volcanic eruptions and lightning. Early atmosphere was composed of methane, ammonia, hydrogen, carbon dioxide, water vapour and under these prevailing condition, these compounds got converted into organic acids, sugars, amino acids etc. These organic molecules reacted together to form self-replicating RNA molecules. These self-replicating RNA molecules were then surrounded by lipids to form primitive anaerobic cell. When oxygen started to appear on atmosphere, most cells died and some of them adapted to become aerobic. Anaerobic cells then engulfed aerobic cells to survive and in this way mitochondria and chloroplast appeared. These cells under millions of years of evolution and interaction among themselves lead to the formation of multi-cellular organisms.