The eye is a complex sensory organ that allows us to see the world around us. The eye works by gathering light from the environment and converting it into electrical signals that can be interpreted by the brain. The basic structure of the eye includes the cornea, iris, pupil, lens, retina, and optic nerve. The cornea is the transparent outer layer of the eye that helps to focus incoming light. The iris is the colored part of the eye that regulates the amount of light that enters the eye through the pupil, which is the black circular opening in the center of the iris. The lens is a clear, flexible structure located behind the iris that helps to focus light onto the retina. The retina is a thin layer of tissue that lines the back of the eye and contains photoreceptor cells called rods and cones. These cells convert light into electrical signals that are sent to the brain via the optic nerve. The rods are responsible for the low light vision and detecting motion, while the cones are ...
Hello everyone our today's topic is Evidences in favour of chemical evolution on primitive earth. In previous posts we talk about the modern theory for appearance of life on earth given by Oparin and Haldane which is divided into two major processes first one is chemical evolution and other one is Biological evolution but this was only a hypothesis until this theory was not proved by giving the evidences in favour of it. And in this post we are going to take a look of that evidences which was in favour of chemical evolution, so come and take a look on evidences in favour of chemical evolution.
There are mainly two evidences in favour of chemical evolution :
In 1953, S.L. Miller, an American scientist created a similar condition at a laboratory scale which were thought to be on primitive earth as mentioned by Oparin and Haldane.
S.L. Miller took almost all the simple compounds which was mentioned by Oparin and Haldane in his theory like CH4, NH3, H2 (in ratio of 2:1:2) and water vapour at 800 degree celsius in a large flask because on primitive earth the temperature was too high. He also created an electric discharge by using two tungsten electrodes as a source of energy as on primitive earth.
He observed that the formation of simple amino acids like glycine, alanine, and aspartic acid take place in his experiments .
Some other scientists also did the similar experiments with same setup and observed the formation of sugars, nitrogen bases, pigment and fats which indicate the theory of chemical evolution was true as mentioned in the modern theory.
There are mainly two evidences in favour of chemical evolution :
(1) Harold Urey and Stanley Miller Experiment:
In 1953, S.L. Miller, an American scientist created a similar condition at a laboratory scale which were thought to be on primitive earth as mentioned by Oparin and Haldane.
S.L. Miller took almost all the simple compounds which was mentioned by Oparin and Haldane in his theory like CH4, NH3, H2 (in ratio of 2:1:2) and water vapour at 800 degree celsius in a large flask because on primitive earth the temperature was too high. He also created an electric discharge by using two tungsten electrodes as a source of energy as on primitive earth.
He observed that the formation of simple amino acids like glycine, alanine, and aspartic acid take place in his experiments .
Some other scientists also did the similar experiments with same setup and observed the formation of sugars, nitrogen bases, pigment and fats which indicate the theory of chemical evolution was true as mentioned in the modern theory.
(2) Evidences from meteorites:
After the analysis of meteorite contents, which was fall on earth scientists found the similar compounds which were thought to be at the time of chemical evolution this indicates that the similar processes as chemical evolution occurring elsewhere in space. This is an interesting fact for astronomers to find and another living planet as earth.
So, with these limited evidences, the first part of the conjectured story, i.e., chemical evolution was more or less accepted.
This version of abiogenesis, i.e., the first form of life arose slowly through evolutionary forces from non-living molecules is accepted by majority. However, once formed, how the first cellular forms of life could have evolved into the complex biodiversity of today is the fascinating story that will be discussed in organic evolution .
So, there is the end of the question that how the first living organism arise on earth and in the next post we are going to start the biological evolution on earth, i.e., how from simple one celled organism todays mega diversity earth were formed on which very complex and variety of organisms were found.
So, there is the end of the question that how the first living organism arise on earth and in the next post we are going to start the biological evolution on earth, i.e., how from simple one celled organism todays mega diversity earth were formed on which very complex and variety of organisms were found.
Comments
Post a Comment