{"id":2013,"date":"2020-07-19T08:41:07","date_gmt":"2020-07-19T08:41:07","guid":{"rendered":"https:\/\/murreeroad.org\/Biology10\/?p=2013"},"modified":"2020-07-19T08:41:07","modified_gmt":"2020-07-19T08:41:07","slug":"q-13-what-is-biological-or-organic-evolution-explain-with-the-help-of-darwins-theory-of-natural-selection","status":"publish","type":"post","link":"https:\/\/murreeroad.org\/Biology10\/q-13-what-is-biological-or-organic-evolution-explain-with-the-help-of-darwins-theory-of-natural-selection\/","title":{"rendered":"Q.13 What is Biological or Organic Evolution? Explain with the help of Darwin\u2019s theory of natural selection"},"content":{"rendered":"

Q.13\u00a0What is Biological or Organic Evolution? Explain with the help of Darwin\u2019s theory of natural selection<\/strong>
\nAnswer:<\/strong>
\nBiological\/Organic Evolution <\/strong>
\nIt is a change in the characteristics of a population or species of organisms over the course of generations.
\nThe changes in an individual are not considered as evolution because evolution refers to populations and not to individuals.
\nProcesses <\/strong>
\nOrganic evolution includes two major processes:
\n\u2022 Alteration in genetic characteristics (traits) of a type of organism over time.
\n\u2022 Creation of new types of organisms from a single type.
\n\"Organic
\n\"Organic
\nTheory of Natural Selection <\/strong>
\nCharles Darwin (1809 \u2013 1882) proposed the mechanism of organic evolution in 1838. It was called as \u201cThe theory of natural selection”. “Darwin proposed after his 5-year voyage on HMS (His Majesty’s Ship) Beagle. He also published a book \u201cOn the Origin of Species by means of Natural Selection\u201d in 1859.
\nEarly response to Darwin’s theory. <\/strong>
\nDarwin theory of evolution was not widely accepted because of lack of sufficient evidence. Modern evolutionary theory began in the late 1920’s and early 1930s.
\nSome scientists proved that the theory of natural selection and Mendelian genetics are the same ideas just as Darwin has proposed.
\nImportance of study of evolution <\/strong>
\nIt determines the ancestry and relationships among different kinds of organisms.
\nTheory of special creation<\/strong>
\nThe anti-evolution ideas support that all living things had been created in their current form only a few thousand years ago. It is known as the theory of special creation.”
\nMECHANISM OF EVOLUTION<\/strong>
\nNatural selection : <\/strong>
\nIt is a process by which the better genetic variations become more common in successive generations of a population.
\nVariations in population <\/strong>
\nAlmost every population contains several variations for the characteristics of its members. These variations are of two types: (i) Morphological Variations (ii) Physiological Variations
\nEvolutionary Fitness of Organism <\/strong>
\nThe central concept of Natural selection is the evolutionary fitness of an organism.
\nFitness means an organism’s ability to survive and reproduce. Organisms produce more offspring than can survive and these offspring vary in fitness.
\nStruggle for survival <\/strong>
\nThese conditions produce struggle for survival among the organisms of a population.
\nFavourable variations <\/strong>
\nThe Organisms with favourable variations are able to reproduce and pass these variations to their next generations.
\nUnfavourable Variations <\/strong>
\nOn the other hand, rate of the transmission of unfavourable variations to next generations is low. It means that unfavourable variations are selected against their transmission to next generations. Examples <\/strong>
\nSkin colour in Mouse . <\/strong>
\nThere are three variations in skin colour of mouse population:
\n\u2022 Light coloured
\n\u2022 Medium coloured
\n\u2022 Dark coloured Cat preys upon light and medium coloured mouse.
\nFirst Generation <\/strong>
\nIn first generation, light coloured mouse is preyed upon by cat. Only medium and dark coloured mouse can make their next generation.
\n\"first
\nNext Generation <\/strong>
\nIn next generation, population again contains light, medium and dark coloured mouse. Cat preys upon the light and medium coloured mouse. Now only dark coloured mouse make new generation.
\nFavourable Variations <\/strong>
\nIt happens in many generations, we will see only the dark coloured mouse in the population.
\nNatural selection <\/strong>
\nAs a result of natural selection, the alleles that give more fitness of characteristics (favourable variations) than other alleles become more common within population.
\nColour Variations in Moth <\/strong>
\nIn England, moths had two variations i.e.
\n(i) Dark coloured moth
\n(ii) White coloured moth .
\nLight coloured tree trunk <\/strong>
\nThe moths used to rest on the light coloured tree trunks (on which white lichens had grown).
\n\"light
\nFavourable variations <\/strong>
\nIn those days, light colour was favourable variation as they were invisible to predatory birds” while resting on light coloured tree trunks. Industrial Revolution
\nAfter industrial revolution in England, the lichens on tree trunks died due to polluted air and naked tree trunks turned dark.
\nThe Unfavourable variation <\/strong>
\nNow the white moth variation became unfavourable or harmful because a white moth resting on dark tree trunk was easily visible to predatory birds.
\nNatural Selection <\/strong>
\nThe natural selection selected dark moths to reproduce. In this way, dark.coloured moth became more common and at last white moths disappeared from population. In this case, the dark colour variation in moth may be considered an adaptation to environment.
\nConclusion <\/strong>
\nSo it is concluded that individuals with favourable yariations become major part of population while individuals with harmful or unfavourable variations become rare.
\n\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Q.13\u00a0What is Biological or Organic Evolution? Explain with the help of Darwin\u2019s theory of natural selection Answer: Biological\/Organic Evolution It is a change in the characteristics of a population or species of organisms over the course of generations. The changes in an individual are not considered as evolution because evolution refers to populations and not… Read More »Q.13 What is Biological or Organic Evolution? Explain with the help of Darwin\u2019s theory of natural selection<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[26],"tags":[],"_links":{"self":[{"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/posts\/2013"}],"collection":[{"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/comments?post=2013"}],"version-history":[{"count":1,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/posts\/2013\/revisions"}],"predecessor-version":[{"id":2018,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/posts\/2013\/revisions\/2018"}],"wp:attachment":[{"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/media?parent=2013"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/categories?post=2013"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/tags?post=2013"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}