This led to the most important scientific development in human history the

This led to the most important scientific development

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This led to the most important scientific development in human history: the theory of evolution.
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-Charles Darwin’s book ‘On the origin of species’ proposes that: (I) all life forms on Earth share common ancestry, (ii) over time new species arise and replace old ones by developing better adaptations to environmental conditions. - Darwin, never really explained how species formed. The science of genetics was not developed at this time yet and without understanding genetics, he could not have grasped the fundamental mechanisms of evolution. Nonetheless, he got the basics right. - Towards the end of Darwin’s life Gregor Mandell started to lay foundations for the science of genetics through painfully slow experimentation. However, full blossoming of genetics had to wait for development of tools needed to do molecular genetics. In 1953 Watson and Crick published a paper on the structure of DNA. Molecular biology is still a thriving field.
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Evidence of Evolution (plus genetic evidence, plus actual experiments evolving plants and animals) Branching Organization Of Life: (a) All living things organized into branching hierarchy of groups nested within groups. (b) Branching structure based on both anatomical and molecular structures. Homology: Organs with strikingly different functions commonly built from the same basic parts, suggesting a common ancestor. Vestigial Structures And Other Imperfections : (a) Many animals have tiny remnants (vestiges) of features they no longer use. (b) Examples include stunted tail bone and appendix in humans, remnants of hips and hind legs in whales and snakes, and remnant side toes on horses. (c) Vestigial structures inherited from ancestors where structures were at one time functional. Embryonic History: (a) All vertebrate embryos start out very similar with gill slits and a long tail inherited from ancient ancestors. (b) Embryonic development sometimes repeats evolutionary history. (c) Gills and tails persist in some adult vertebrate but are lost during human development into adults. Biogeography: (a) On many continents, unrelated animals evolved to occupy similar ecological niches. (b) Result was that unrelated animals developed similar physical features. (c) Example: Australian Marsupials (pouched animals) unrelated to and geographically separated from Placental mammals of Europe and North America. The Marsupials and Placentals, however, have remarkably similar descendants. Similarities in the features of Marsupials and Placentals probably resulted from both groups filling similar ecological niches on different continents.
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- Another key fact that our ancestors did not know, is how old the Earth is and how much time life had to evolve and diversify. - Hence they assumed that all plants and animals around us were created as we see them in some act of divine genesis.
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Darwin Gets It Right Again “All living things have much in common, in their chemical composition, their germinal vesicles, their cellular structure and their laws of growth and reproduction… therefore I should infer…that probably all
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