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Conservation and Biodiversity: An Introduction to species, diversity and natural selection

Conservation and Biodiversity: An Introduction to species, diversity and natural selection. Darlene Oehlke ESS Nido de Aguilas. Species:. Organisms that are able to reproduce to produce live, fertile offspring. How many species exist?. Between 1.4 – 2.0 million species are known.

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Conservation and Biodiversity: An Introduction to species, diversity and natural selection

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

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

  3. How many species exist? • Between 1.4 – 2.0 million species are known. • Large animals and plants are easiest to observe. • Smaller organisms, such as fungi, insects are harder to find and identify. • Current estimates of the number of species ranges between 10 to 100 million • Resource: Course Companion

  4. The average existence of a species varies • Mammals: 1 million years • Arthropods: 10 million years

  5. Biodiversity The variety of genes, species, and ecosystems within a region. The variability amongst living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and ecological complexes of which they are a part.

  6. Genetic Diversity • A level of biodiversity that refers to the total number of genetic characteristics in the genetic makeup of a species. • The range of genetic material present in the gene pool.

  7. Genetic diversity within a population • A healthy population usually contains a good deal of genetic diversity, individuals varying considerably. • This variability provides the basis for natural selection and evolution.

  8. Low genetic diversity • A species that has been brought close to extinction, and then recovered contains less genetic diversity and thus displays less variability. • A small population can contain fewer genes in total than a large one.

  9. Seals hunted to near extinction • Some species of seals that were reduced to a tiny population in the nineteenth century by hunting, have, in recent decades have increased in numbers. • The "new" population is genetically impoverished and displays less variability than the original one.

  10. Large genetic diversity • Researchers have discovered varieties of barley with a surprisingly high level of genetic diversity in Eritrea. • This may help breed drought and disease resistant barley. http://www.scidev.net/en/news/high-genetic-diversity-discovered-in-eritrean-barl.html

  11. Loss of genetic diversity • http://www.life.illinois.edu/ib/335/rainforestdeforestation.jpg

  12. Species Diversity • Species diversity: the number of species in an area and their relative abundance in a single habitat.

  13. The tropics and coral reefs are regions with high species diversity.

  14. Habitat Diversity • The diversity of a place at the level of ecosystems. • The variety of habitats within an area. • These are sometimes called microhabitats.

  15. The Vosges du Nord Biosphere Reserve is an area with a large habitat diversity.

  16. Habitat Diversity • Compare the habitat diversity of the tundra to the tropical rainforest.

  17. Endemic Species on Islands • Oceanic island ecosystems show a high level of endemism. • Endemic = exclusively native to a place

  18. The Hawaiian Islands and the Galapagos are centres of considerable biodiversity.There are many endemic species on the island

  19. Hot spots: Locations containing endemic plants and serious levels of habitat loss • The biodiversity hotspots hold especially high numbers of endemic species. • Hotspots face extreme threats and have already lost at least 70 percent of its original natural vegetation. • Over 50 percent of the world’s plant species and 42 percent of all terrestrial vertebrate species are endemic to the 34 biodiversity hotspots.

  20. Chilean Hotspot: Chilean Winter Rainfall- Valdivian Forests Threatened species: • Darwin’s frog • mountain vizcacha • Araucaria Forests • Andean Cat http://www.biodiversityhotspots.org/xp/hotspots/chilean_forests/Pages/default.aspx

  21. Natural selection • Speciation occurs as a result of the isolation (geographical or reproductive) of populations. (Two different species arise in response to different environmental conditions. • Diversity exists within the population randomly. • If the trait helps the individual survive, it is passed onto the offspring.

  22. Natural Selection • Organisms possessing such advantageous characteristics increased 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.

  23. Peppered moths in 19th Century England

  24. 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.

  25. 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

  26. 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.

  27. 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.

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

  29. 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

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

  31. Ecosystem stability and diversity Greater habitat diversity leads to greater species and genetic diversity A complex ecosystem, with its variety of nutrient and energy pathways, provides stability An ecosystem’s capacity to survive change may depend on diversity, resilience and inertia.

  32. Simplification of ecosystems • Human activities often simplify ecosystems, rendering them unstable, for example, North America wheat farming versus tall grass prairie

  33. Changes in diversity with succession • The pioneer community is less diverse than the climax community. • Human activities modify succession, for example, logging, grazing, burning

  34. 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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