• Unit 5-Biodiversity

    Key Points:
    • We do not know how many species are alive on Earth but we do kknow that many are becoming extinct or are endangered.
    • Some species are more prone to extinciton than others.
    • Threatened species are on the IUCN Red List.
    • The mechanism for speciation is isolation of populations and natural selection.
    • Movement of the Earth's plates over geological time has increased biodiversity.
    • Biodiversity is lost through natural hazards, habitat degradation, agriculture, introduction of non-native species, polution, hunting and harvesting.
    • Tropical reainforests are the biome with the most diodiversity and they are under threat.
    Key Words:
    biodiversity species diversity habitat diversity
    diversity index genetic diversity extinction rates
    background extinction rate mass extinction hotspots
    endemic species exotic species plate tectonics
    continental drift keystone species natural selection
    extinct endangered vulnerable
    lithosphere core mantle
    crust subduction mid-Atlantic ridge
    evolution physical barriers land brdiges

Last Modified on February 23, 2015