B3: Life on Earth

Adaptation and Variation
1. Species is a group of organisms that can breed together to produce fertile offspring
2. Species adapt to theri favourite envoronment
  1. Fish are adapted to aqatic environments
    1. Gills
    2. Streamlined bodies
  2. Cactus is well adapted to desert conditions
    1. Shallow but extensive roots which absourbs water
3. Variation in species
  1. Some variation is genetic and is passed on
    1. Mutations
      1. Develop new characteristics
Natural Selection
1. process that cause evolution
  1. Survival of the fittest
  2. Organisms compete for resorces
    1. Best ones win and survive
      1. Best ones breed and evolution occurs
2. Selective breeding
  1. Humans choos what gets bred
    1. eg - cows that produce lots of milk
Evolution
1. Life began 3500 million years ago
2. The process of evolution can produce new species
  1. Sometimes the same species become so isolated they cant interbreed
  2. Natural selection
    1. Mutations
  3. Environmental change
  4. Evidence
    1. Fossils
      1. Get more complex as time goes on
    2. DNA
      1. Similarities in DNA to see how life has evolved
3. Charles Darwin
  1. Lamarck argued that more used characteristics
    1. become more developed
Biodiversity and Calssification
1. Biodiversity includes
  1. Number of species on earth
  2. Range of different types of organisms
  3. Genetic variation of same species
2. Maintaining biodiversity is important
  1. More plants, more resources
    1. New medicines
3. rate of extinction is increasing
  1. Humnas destroying habitats
  2. Humans hunting animals
4. Classification
  1. Kingdoms
    1. Plants, fungi, bacteria, algae, animals
  2. Divided into groups, eventually get to species
  3. Number in a class decreases, characteristics in common increases
Interactions between organisms
1. Everything needs light, food, O2, CO2 and water
2. Rely on eachother, interdependance
  1. One animal dies, has knock on effects to other animals
  2. Even possibly extinction
Energy in Ecosystems
1. Energy comes from the sun
2. Energy is transfered at each stage but some is lost
  1. respiration
    1. heat
    2. waste products
  2. uneated parts of organism
  3. efficincy = (energy available to next stage/energy that was available to previous stage) x 100
The Carbon Cycle
1. Whole thing powered by photosynthesis
2. Eating passes the carbon from plants to animals
  1. Both animals and plants respire releasing it back into the air
    1. Plants and animals die and decompose whch releases CO2
    2. Burning of fossil fuesl released CO2
The Nigtrogen Cycle
2. Decomposers - decompose protein and exretion into ammonia
3. Nitrifiing bacteria - turns ammonia in decaying matter to nitrates
4. Nitrogen fixing bacteria - turns atmospheric N2 into nitrogen compounds for plants
5. Denitrifing bacteria - turns nitrated back into N2 gas
  1. Has no benefit to living organisms
Measuring environmental change
1. Non living indicators
  1. Temperature
  2. Nitrate level
    1. Increase - sewage in water
      1. CO2 level
2. Living indicators
  1. Lichens
    1. lots of - clean air
  2. Mayfly nymphus
    1. more - bad water
  3. Phytoplankton
    1. more - clean water
Sustainability
1. Meeeting the needs of todays population without harming the environment for future generations
2. Packaging materials can be more sustainable
  1. Use renewable materials
    1. use less energy
      1. Create less polution

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B3: Life on Earth

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