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Showing posts from July, 2019

Eyes: How They Work, Anatomy and Common Condition

 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 resp
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Evidences of Organic Evolution

Hello everyone, In previous posts we talk about the journey of evolution from non-cellular life to prokaryotes and after that eukaryotes and also we would see the various theories which try to explain this journey, and also the evidences of the theory which explain this journey in best way, which was Modern theory given by Oparin and Haldane.Now this part end i.e., how the first life originated on earth now we will discuss evolution of life forms on earth i.e., the changes in flora and fauna that have occurred over millions of years on earth. When we think about evolution the first question arise in our mind is, What is Evolution?  The word evolution means to unfold or unroll or to reveal hidden potentialities. Evolution simply means an orderly change from one condition to another. The term evolution was introduced by Herbert Spencer and It can be best explained by Darwin's Concept of "Descent with modification" which we will discuss in our Upcoming posts.
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Evidences of Chemical Evolution on primitive Earth

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 : (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 h
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Biological evolution on primitive earth

   Biological evolution on primitive earth     In previous post we talk about chemical evolution on primitive earth that how the protoplasmic constituents were formed and where? Now today we move to the biological evolution and start talking about how these protoplasmic constituents aggregate and form the first living cell and after that eukaryotic cell, so lets start. Biological evolution also known as biogeny . We will study the biological evolution in four steps: (1) Origin of protobionts:  Macromolecules which were synthesized abiotically in primitive oceans later came together and formed large colloidal drop like structures named as protobionts. It is believed that they were the clusters of proteins, polysaccharides, lipids, nucleic acids, etc. In these protobionts all prtoplasmic constituents were present but yet it is not reproduce or exhibit metabolism due to inactive proteins and nucleic acids but they exhibit growth by absorbing molecules from their surrounding
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Chemical evolution on primitive earth

   Chemical evolution on primitive earth     In previous post we talk about various theories which were try to solve the puzzle of life i.e. how first life appear on earth. In the race of these theories, The modern theory were come which is the most acceptable theory of origin of life.This theory was given by two scientist Oparin and Haldane, so it is also known as Oparin-Haldane theory. This theory was published by Oparin in his book 'Origin of life' . He told that life originated in sea water, so water is very essential for origin of life. They divided the origin of life in two major process, first the Chemical Evolution and second one is the Biological Evolution . In this post we talk about the Chemical Evolution, so lets begin. Chemical Evolution also known as chemogeny. This is the story after the big bang when our earth was too hot and we called this the Primitive earth.On primitive earth the atmosphere was very adverse, High temperature, volcanic storms, lighte
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