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Introduction |
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Heredity is the transmission of characteristics, physical or mental from parents to offspring that is, from one generation to the successive generation. |
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Accumulation of Variation During Reproduction |
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All round us we see different organisms from the lowest forms to the highest. Species differ from each other. However, the variation we focus relates to the differences among individuals of a species. |
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Heredity |
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An important result of the reproductive cycle is production of similar featured individuals for generations. The transmission of characteristics through successive generations refers to heredity. |
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Evolution |
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It is clear that there is an inherent tendency to variation in sexual reproduction. An error in DNA copying during sexual reproduction also causes changes as we shall see. |
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Acquired and Inherited Traits |
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The theory put forth by Darwin and Wallace gained wide acceptance. However, in the light of modern evidences, it was slightly modified and called Neo-Darwinism. |
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Speciation |
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Speciation is the evolutionary process by which new biological species arise. A new species will be a group of individuals distinguished from the original one because by nature only interbreeding takes place amongst their own species. |
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Evolution and Classification |
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The central ideas of evolution are that life has a history-it has changed over time-and that different species share common ancestors. |
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Evolution by Stages |
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The evolutionary process has developed over millions of years. Lineages evolved and split and modifications occurred gradually in stages. |
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Evolution Should not be Equated with Progress |
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Evolution of life has been taking place for about 3.8 billion years of time. When we view macroevolution - the large-scale evolutionary history of life. |
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Summary |
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Mendel postulated that there are certain physical entities called the factors that are responsible for the transmission of characters; these factors are now called genes. |
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Question and Answers |
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Multiple Choice Questions |
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