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  • Created by: Karimoja
  • Created on: 24-12-14 16:40
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  • Speciation
    • Fossils
      • All living things come from simple life forms
        • These appeared on earth over 3 billion years ago
        • Changed slowly over time through evolutuon
        • Evidence of these things are fossils
      • Remains of organisms in rocks
      • How they are formed
        • Hard parts of animals decay slowly and are replaced by minerals forming a fossil
        • Marks like footprints and holes from roots that have been filled with minerals
        • From parts of organisms that aren't decayed due to wrong conditions e.g. ice fossils
          • Conditions needed for decay are oxygen, warmth and mosture
      • Reasons there aren't more
        • Many early forms of life were soft bodied and decayed fast
        • Many fossils have been destroyed by geological activity
    • Why animals become Extinct
      • Climate change
        • Not adapted to live in new climate and so die
      • Natural Disaster
        • Can cause climate change and affect large areas
      • New Competition
        • Fight for food, water and space, poorest competitor dies
      • New Predators
        • New unknown threats, don't know how to defend themselves
      • New Disease
        • Not protected from new diseases
    • How new species are formed
      • A species is a group of similar organisms that can breed together to produce fertile iffspring
      • 1. Isolation
        • 2 populations of a species become seperated
      • 2. Genetic Variation
        • In each population there is a range of characteristics
      • 3. Natural Selection
        • Alleles of a characteristic become more common
      • 4. Forms a new species
        • The population becomes so different that successful interbreeding is no longer possible


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