EARTH AND LIFE SCIENCES Biology is a science that deals with all forms of life, including their classification, physiology, chemistry, and interactions. The term was introduced in Germany in 1800 and popularized by the French naturalist Jean-Baptiste de Lamarck as a means of encompassing the growing number of disciplines involved with the study of living forms. Where did life begin? Theories: Theory of Special creation, in accordance with the Book of Genesis, that every species was individually created by God in the form in which it exists today and is not capable of undergoing any change. Cosmozoic Theory (Panspermia Theory) – the idea proposed by Richter in 1865 and supported by Arrhenius (1908). According to this theory, life has reached the planet Earth from other heavenly bodies such as meteorites, in the form of highly resistant spores of some microorganisms. The spores of some microorganisms are called cosmozoa or panspermia. Theory of Spontaneous Generation also known as Abiogenesis, the idea that life arose from nonlife more than 3.5 billion years ago on Earth. Abiogenesis proposes that the first life-forms generated were very simple and through a gradual process became increasingly complex. Coacervate theory , it is expressed by the Russian biochemist A.I. Oparin in 1936 suggesting that the origin of life was preceded by the formation of mixed colloidal units called coacervates. Miller-Urey hypothesis. The first hypothesis where lightning could have operated the synthesis reactions in the Earth’s early atmosphere was tested by in 1953. It provided the first evidence that organic molecules needed for life could be formed from inorganic components. Fossil Evidence Fossil evidence indicates that life on Earth appeared about 3.5 billion years ago in the oceans. Early forms of life Biogenesis Theory, life is derived from the reproduction of other life, was presumably preceded by abiogenesis, which became impossible once Earth’s atmosphere assumed its present composition. Primordial Soup Theory According to primordial soup theory proposed by Alexander Oparin and John Haldane, life started in a primordial soup of organic molecules. Some form of energy from lightning combined with the chemicals in the atmosphere to make the building blocks of protein known as the amino acids. The first forms of life are believed to have appeared some 3.5 billion years ago. Photosynthetic organisms are organisms who make their own food by utilizing the energy from the sun and the carbon dioxide in the atmosphere. The process of photosynthesis produced more oxygen that changed the Earth’s early atmosphere, allowed oxygen-breathing organisms to exist. Cyanobacteria (blue-green algae) are the first photosynthetic organisms to form.
