b3 life on earth **

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  • Created by: moorelm02
  • Created on: 30-04-16 14:57
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  • B3-life on earth
    • Adaptation
      • A SPECIES is a group of organisms that can breed together to produce fertile off spring.
      • Every living thing needs resources from its environment - 1.Light(pl), 2.Food(an)(minerals=plants), 3.Oxygen(pl+an), (CO2-pl), 4. Water(all)
      • Cactus- thick stem= store H2O, rounded shape= small surface area reducing H2O loss, shallow extensive roots=water
      • Fish- gills=extract O2 from H2O, tail fins=large surface area, streamlined, swim bladder
    • Natural selection
      • Species can change to adapt to their environment through Natural Selection
      • Natural selection causes evolution and means "survival of the fittest"
      • Survival characteristics get passed down because more likely to survive through competition of limited resourcesUntitled
    • Selective breeding
      • Selective breeding is when humans choose a feature they want to appear in the next generation e.g. most milk
    • Evolution
      • Life began around 3500 million years ago
        • Fossil records + DNA provide evidence for evolution
          • Fossil records show species getting more complex over time, Mutations in DNA still similar/related to living species
      • Charles Darwin- theory of evolution by natural selction, by observations Untitled
        • Lamarck's rejected for Darwin's, acquired characteristics don't have a genetic basis = can't pass on
          • Lamarck- theory if characteristic used more= more developed = passed to offspring
      • Factors to make different  species: Different  mutation create different features in the organisms, Natural selection, Environmental changes = different  adaptations
    • Interactions between organism
      • Every living thing needs resources from its environment - 1.Light(needed by plants to make food ),     2.Food(for animals)(minerals=plants),    3.Oxygen(plants +animals), (CO2 (carbon dioxide -plants),               4. Water(all)
      • Any change in the environment has all effects on the food cycle e.g. less food = competiton = extinction
      • 3 changes that can cause extinction:
        • 1. Environmental conditions change- can't adapt
          • 2. New species intro-ed, competitor, disease organism, predator of them
            • 3. An organism in its food web becomes extinct
    • measuring environmental change
      • environmental change can be measured with non-living idicators
        • Environmental change can be measured by temperature measurements, nitrate level-water, CO2 level-air
      • environmental change be measured with living indicators
        • lichen- air pollution can be monitored by looking at particular types of lichen. which are sensitive to levels of sulphur dioxide. the number and type of lichen at a location will indicate how clean the air is,
        • Mayfly Nymphs- sensitive to level of oxygen levels in the water. if the water's clean if there you will find mayfly nymphs.
        • phytoplankton increase when levels of nitrates+ phosphates in water increase- this is called algal bloom. algal bloom can be used to indicate water pollution
    • sustainability
      • Sustainability means meeting the need's of today's population without harming the environment so that future generations can still meet their own needs
      • packaging material can be made more sustainable
        • Using renewable materials- a lot of packaging comes from non- renewable resources e.g plastic. swap to use material like paper and card can improve the sustainability as the resources can be replaced. e.g plant more trees.
          • using less energy- making packaging from recycled material uses less energy. this means the environment isn't damaged as much because less energy been used.
            • creating less pollution- making plastics biodegradable is more sustainable because they will rot away more easily and causes less pollution.
    • Biodversity and classification
      • Biodiversity- number of different. species, range of different types of organisms, genetic variation between organisms of same species
      • Maintaining biodiversity-important. more plants= more resources for new food crops, chemicals in living things= new medicines
      • The rate of extinction of species increasing
        • Correlation between growth of population+ no. of species extinction
          • Humans can cause extinction directly(e.g. hunting)indirectly(destroy habitat/intro new species)
      • classification
        • Millions of species grouped into 5 kingdoms- bacteria, fungi, algae, plants, animals.
          • Each kingdom is divided into more groups and they are divided into more groups. until you get a species.
            • As you go down the groups the number of types of organisms in each one decreases, but the number of characters increases.
        • classification-shows us the evolutionary relationships between the different organisms
    • Energy in the eco system
      • Efficiency of energy transfer- efficiency= energy available to next stage ÷ energy that was available to previous stage
      • Plants use 10% of the sun's energy during photosynthesis and the 90%'s lost
        • Energy form the sun is the source of energy for nearly ALL life
          • Energy is lost from organism to organism in the food cycle
            • The energy is lost in respiration, heat (to surroundings), waste, movement
              • Remaining energy is transferred to predator when eaten or eaten waste.
    • Variation
      • variations are individual of the same species that look slightly different from each other. Some variation is genetic so it can be passed on to the off spring.
        • one cause of genetic variation is genes change, these changes are called mutations.
          • mutations can be caused by outside factors like radiation or chemicals. also by mistakes when genes are copied during cell division.
            • if mutations occur during the formation of body cells they usually have little effect, though they can lead to cancer.
              • if they occur during formation of sex cells they have more effect because the mutation will then be passed on to all the cells of the off spring
                • This can cause the offspring to develop new characteristicssome might be harmful towards the offspring and some might help it survive.
  • 2. New species intro-ed, competitor, disease organism, predator of them
    • 3. An organism in its food web becomes extinct
  • if they occur during formation of sex cells they have more effect because the mutation will then be passed on to all the cells of the off spring
    • This can cause the offspring to develop new characteristicssome might be harmful towards the offspring and some might help it survive.

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