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Theory Of Evolution of Natural Selection by DARWIN


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Theory of Evolution

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Theory Of Evolution of Natural Selection by DARWIN

  2. 2. Key Terms • Mutation: creation of altered DNA • Gene flow: gene movement from one population to another • Genetic variation is affected by gene flow and it allows natural selection to occur • Charles Darwin • Natural selection • Survival of the fittest • Family Tree • “Descent with modification”
  3. 3. as a Child  Naughty  Clumsy  Athletic  Gullible  Lazy  Slow learner  Shy
  4. 4. Darwin’s Love for Natural Science  Was taught the classics, ancient history, and Greek at Revd. Samuel Butler's school and found it to be extremely boring  He developed his interest for natural science in activities outside of school  Hiking  Book Reading  Chemistry
  5. 5. Darwin and Medicine  Darwin was admitted to Edinburgh University, in Scotland  Many members of his family including his dad were in the medical field  Assisted at his dad’s medical practice  Again he found most of his school studies a bore  Scared of blood
  6. 6. A Further Interest in Science  Darwin participated in many things outside of school that sparked his interest in natural science  Stuffing Animals  Natural History Book  Natural History Museum  Plinian Society  Robert Grant
  7. 7. The Voyage of the Beagle • Ships naturalist on a trip around the world aboard the HMS Beagle • During his travels, Darwin made numerous observations and collected evidence that lead him to propose a revolutionary hypothesis about the way life changes
  8. 8.  Was a religious orthodox that received proper religious schooling  Darwin began to research the origin of species and saw that the species adapted to their environment of time  While coming up with the laws of natural selection, Darwin became less religious  In contrast with the churches views believed that God initiated the process but did not create each species already fit for their environment Religion vs. Science
  9. 9. The Theory of Natural Selection  Darwin’s several observations on nature: variation, heritance, competition, adaptation.  Natural Selection is a very simple concept!  Individuals with favored traits → higher chance of reproduction → more offspring with the traits  Thus, the certain traits will become popular in the population over generations. Background Inference
  10. 10. The Theory of Natural Selection Survival of the fittest
  11. 11. Family Tree Evolution • Darwin’s another observation on bird species in Galápagos Islands in 1835 • Common ancestor from the mainland of South America • “Descent with modification”
  12. 12. Stages of Development
  13. 13. Keys in Natural Selection Natural Selection is… • The evolution of the population, not the evolution of the individuals • Dealing with heritable traits, not acquired characteristics • Based on the environment; being favored in one place does not mean it is also favored in a different place
  14. 14. Artificial Selection • Darwin was convinced that a process like artificial selection occurs in nature • High birth rates and a shortage for resources would force organisms into a competition for resources
  15. 15. Summary of Darwin’s Theory 1. Individual organisms in nature differ from one another. Some of this variation is inherited 2. Organisms in nature produce more offspring than can survive, and many of those that survive do not reproduce. 3. Because more organisms are produced than can survive, members of each species must compete for resources. 4. Because each organism is unique, each has different advantages and disadvantages in the struggle for existence.
  16. 16. 5. Individuals best suited to their environment survive and reproduce most successfully. The characteristics that make them best suited to their environment are passed on to offspring. Individuals whose characteristics are not as well suited to their environment die or leave fewer offspring. 6. Species change over time. Over long periods, natural selection causes changes in the characteristics of a species, such as in size and form. New species arise, and other species disappear. 7. Species alive today have descended with modification from species that lived in the past. 8. All organisms on Earth are united into a single tree of life by common descent.
  17. 17. Thanks…