Introduction to evolution

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  Evolution is a theory in biology postulating that the various types of plants animals and other living things on earth have their origin in other pre-existing and that the distinguishable differences are due to modifications in successive generations
•   theory of evolution it is a scientific theory is a well supported testable explanation of phenomena that have occurred in the natural world
• Charles darwin voyage is on hms beagle
• Charles darwin published the book the origin of species in 1859
• Darwin visited argentina and australia which had similar grassland ecosystems and those grasslands were inhabited by very different animals, neither argentina nor australia was home to the sorts of animals that lived in european grasslands
• Darwin collected the preserve remains of ancient organisms called fossils and some of those fossils resembled organisms that were still alive today
• Darwin was fascinated in particular by the land tortoises and marine iguanas in the galapagos island and giant tortoises varied in predictable ways from one island to another, the shape of tortoises shell could be used to identify which island a particular tortoise and inhabited
• These are the animals found in the galapagos island the land tortoises, the darwin finches, the blue footed booby, and marine iguanas.
• These are the people that shape darwin's thinking about evolution first is James Hutton, Charles Lyell, Jean Lamarck, and Thomas Malthus.
• James hutton 1795 theory of geological change this means forces change earth's surface shape he also said that changes are slow and earth is much older than thousands of years
• Charles lyell

  Book: Principles of Geography

  geographical features can be built up or torn down
• Catastrophism such as volcanoes floods and earthquakes are example of catastrophic events that were once believe responsible for mass extinctions and the formation of all landforms
• Gradualism said canyons carved by rivers show gradual change. it is the idea that changes on earth occurred by small steps over long periods of time
• Uniformitarianism such as rock strata demonstrate that geologic processes which are still occurring today add up over long periods of time to cause great change
• Thomas malthus is 19th century english economist he about the increase in population
• Jean Lamarck

  • Lamarcks theory of evolution
  • Inheritance aquired traits
  • Use and disuse
• Russell wallace wrote an essay summarizing evolutionary change from his fieldwork in malaysia
• Russell wallace wrote an essay summarizing evolutionary change from his fieldwork in malaysia
• Observe differences among island species

  • Variation
  • Adaptation
• Nine distinct species of finches in the galapagos islands where all very similar for each other except for their beaks
• Darwin's voyage on HMS Beagle was a five-year expedition around the world, departing from England in December 1831.
• Natural Selection: The process by which individuals with traits that are better suited to their environment survive and reproduce more than individuals with traits that are less suited
• Artificial selection is the process of selecting for a particular characteristic in a population.
• Population

  • All the individual species that live in a specific geographical area and that can interbreed
• Population

  • All the individual species that live in a specific geographical area and that can interbreed
• Key concepts derived from Darwin's theory

  • Natural selection explains how evolution can occur
  • Variation
  • Overproduction
  • Adaptation
  • Descent with modification
• Other factors

  Selective pressure

  • Factors in the Environment select for or against a genetic trait
• Sexual selection

  intra sexual- males compete against to each other to win a mate

  Inter sexual- feamles choose a mate based on specific male traits