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Conservation and Biodiversity: An Introduction to natural selection

Conservation and Biodiversity: An Introduction to natural selection. Darlene Oehlke ESS Nido de Aguilas. Species:. Organisms that are able to reproduce to produce live, fertile offspring. Natural selection.

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Conservation and Biodiversity: An Introduction to natural selection

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  1. Conservation and Biodiversity: An Introduction to natural selection Darlene Oehlke ESS Nido de Aguilas

  2. Species: • Organisms that are able to reproduce to produce live, fertile offspring

  3. Natural selection • There are more organisms than the habitat can support, thus there is a competition for resources. • Diversity exists within the population, so organisms of the same species posses different traits. • If a trait helps the individual survive, it is passed onto the offspring.

  4. Natural Selection • Organisms possessing such advantageous characteristics increase the proportion of beneficial characteristics in the population. • Pressure from the environment influences the proportion of a population displaying a characteristic: in this way organisms become adapted to their environment and way of life.

  5. Peppered moths in 19th Century England

  6. Speciation: Evolution of a new species • If a small population is isolated on a remote island, desert oasis, or mountain peak, a new species may evolve quite quickly because: • The gene pool is small • New genetic material does not come in from elsewhere. • The population adapts to a specialised environment and the traits of the population change.

  7. Isolation can lead to different species Isolation of populations can lead to different species being produced that are unable to interbreed to yield fertile offspring. • Geographic Isolation • Reproductive Isolation

  8. Geographic Isolation • The voles on islands off the coast of Scotland have been separated from the populations on the mainland for just a few thousand years - since the rise in sea level following the Ice Age.

  9. Isolation of species example • In Lake Victoria there are 170 species of cichlids; in Lake Tanganika 126 species, and in Lake Malawi 200 species. These lake faunas have, probably been isolated from each other for millions of years.

  10. Galapagos Finches • The Galápagos Islands' 14 species of finches all evolved from one ancestral species • The finches arrived 2-3 million years ago.

  11. Behavioural Isolation • If courtship differences which prevent reproduction.

  12. Plate tectonics • Plate activity in generates new and diverse habitats, thus promoting biodiversity. • Gene pools are isolated by moving plates. Natural selection over time creates new species

  13. http://www.livescience.com/images/pangea_animation_03.gif

  14. In pairs.. • Outline the mechanism of natural selection as a possible driving force for speciation. • State how place activity has influenced evolution and biodiversity.

  15. Bibliography • State of the Planet http://www.bbc.co.uk/nature/programmes/tv/state_planet/habitat.shtml • IB Booklet Biodiversity and Conservation • Course Companion

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