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Evolution of life


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Evolution of life

  1. 1. Evolution of Life
  2. 2. CHARLES DARWIN 1809 – 1882 born in Shrewsbury in Western England naturalist when he was 16 years old enrolled at Cambridge University to become clergy man Reverend John Henslew Captain Robert FitzRoy preparing the survey ship HMS Beagle for a voyage around the world.
  3. 3. CHARLES DARWIN 22 years old collected South American plants and animals Lyell’s Principle’s of Geology (rocks containing the fossils must have been raised there by a long series of similar earthquakes collected birds in the Galapagos He hypothesized that the Galapagos had been colonized by organisms that had strayed from South America
  4. 4. DARWIN INTRODUCES A REVOLUTIONARY THEORY November 24, 1859 Charles Darwin published On the Origin of Species by means of Natural Selection it is focused in biologists’ attention on the great diversity of organisms
  5. 5. TWO MAJOR POINTS OF DARWIN1. evidence that many species of organisms presently inhabiting Earth are descendants of ancestral species that were different from the modern species.2. He proposed a mechanism for this evolutionary process, which he termed natural selection.
  6. 6. EVOLUTION A change over time in the genetic composition of a population gradual appearance of all biological diversity, from the earliest microbes to the enormous variety organisms alive today. Evolutionary adaptation an accumulation of inherited characteristics that enhance organisms’ ability to survive and reproduce in a specific environment
  7. 7. NATURAL SELECTION AND ADAPTATION struggle for existence and the capacity of organism to ‘overreproduce unequal ability of individuals to survive and reproduce can increase the adaptation of organisms to their environment
  8. 8. NATURAL SELECTION AND ADAPTATION Artificial Selection humans have modified other species over many generations by selecting and breeding individuals that possess desired traits
  9. 9. THE EVOLUTION OF DRUG- RESISTANT HIV Human Immunodeficiency Virus its connection to natural selection is that it is more on the process of editing than a creative mechanism A drug does not create resistantpathogens, it selects for resistantindividuals that were already present inthe population
  10. 10. THE EVOLUTION OF DRUG- RESISTANT HIV Natural Selection depends on time and place it favors those characteristics in a genetically variable population that increase fitness in the current, local environment what is adaptive in one situation maybe useless or harmful to others
  11. 11. HOMOLOGOUS STRUCTURE Comparison of body structures between species represent variations on a structural theme that was present in their common ancestor