Understanding our Environment

Classification
1. Kingdom
  1. Phylum
    1. Class
      1. Order
        Family
        Genus
        Species
2. Species can breed to create fertile offtspring
3. Binomial System: Genus - species
4. Problems with classifying
  1. Organisms at different evolutionary stages
    1. Archaeopteryx : Bird-reptile
  2. Bacteria
    1. Reproduce asexually
  3. Donkey-horse interbreeding
    1. Mules: Infertile, have no species
5. Evolution
  1. Consider similarities and differences
    1. E.g. Dolphins and bats both mammals, related through evolution.
Energy Flow
1. Biomass/ Number Pyramids
  1. May differ if:
    1. Producer is large
    2. Small parasite on large animal
  2. Biomass flaws:
    1. Dry mass means no water: Kills the organism
    2. Organisms feed on different trophic levels
2. Loss of energy:
  1. Growth
  2. Excretion
  3. Egestion
  4. Respiration
  5. Decomposers use this waste
  6. 90% loss per trophic level
  7. Growth energy/energy input = efficiency
Recycling
1. The Carbon Cycle
  1. Removed from air: Photosynthesis
    1. Released into air: Respiration, decomposition, combustion
    2. CO2 absorbed by oceans
2. The Nitrogen Cycle
  1. Plants take in nitrogen in a 'nitrate' form
    1. Food chains pass on the nitrogen
      1. Nitrogen compounds in dead organisms broken down by decomposers
        Nitrogen in the soil once again
  2. Microorganisms involved
    1. Decomposers: Convert proteins into urea/ammonia
    2. Nitrifying bacteria: Ammonia > nitrates
    3. Denitrifying bacteria: Nitrates > nitrogen gas
    4. Nitrogen fixing: Nitrogen gases > Nitrogen compounds
      1. Live in root nodules of leguminous plants
Interdependence
1. Ecological niche: Habitat and an organism's role
  1. Niche-similar organisms = more competition
    1. E.g. Harlequin ladybird vs. UK native in 2004
2. Predator-Prey
  1. Both show cyclical changes (up-down)
    1. More prey > More predators survive
      1. More predators > Prey eaten
        Predators starve > Numbers drop
    2. Short lag time due to reproduction
3. Parasitism/Mutualism
  1. Host suffers, parasites gain
    1. Fleas
    2. Tapeworm
  2. Bees' pollination rewarded by nectar
  3. 'Cleaner' fish in coral reefs eat dirt on larger fish
  4. Leguminous Pea-plant
    1. Nodules contain nitrogen-fixers
      1. Bacteria convert nitrogen to usable form
        Pea, in return, lends sugars produced in P.synth
Adaptation
1. Anatomical adaptations to cold:
  1. Insulation e.g thick fur, blubber
  2. Migration/Hibernation:
    1. Birds fly to warmer locations
    2. Bears hibernate, slow down body processes
  3. Specialist adaptations:
    1. Anti-freeze proteins in cells (Codfish)
    2. Penguins "counter-current" exchange:
      1. Warm blood entering flippers passes heat to cold blood leaving flippers
2. Hot/Dry Adaptations
  1. Animals have large 'Surface area - volume ratio'
    1. Heat loss
  2. Behavioural:
    1. Seek shade midday
  3. Dry Conditions:
    1. Camels have concentrated urine
    2. Small spines on cacti minimise water loss
3. 'Extremophiles'
  1. Bacteria that live in 100'c+ conditions
4. Specialists v. Generalists
  1. Polar bears
  2. Rats
  3. Generalists lose in certain habitats
Natural Selection
1. Charles Darwin
  1. 1850s
  2. "Better-suited organisms are more likely to survive. They pass on their traits."
    1. We now know GENES are passed on
  3. Modern Summary:
    1. Variation in species
      1. Competition for food /habitat to survive
        Survival of the fittest: The best adapted will survive
        Successful traits passed on
  4. Opposition:
    1. Christianity was still influential
    2. Jean Baptiste:
      1. "Giraffes acquired long necks in order to feed: They pass this on."
    3. Darwin now accepted due to new 'genes' knowledge
2. Peppered Moths:
  1. Darker moths survive in polluted areas. Their numbers increase.
3. Bacteria becoming RESISTANT
Population and Pollution
1. USA and Europe using most fossil fuels
2. Carbon Footprint: Total greenhouse gas / person / time
3. Measuring Pollution
  1. Equipment (Direct)
    1. Oxygen probes
    2. Nitrate indication chemicals
  2. Indicator Organisms
    1. Presence/Absence used to estimate pollution
      1. Mayfly larva lives CLEAN water
      2. Bloodworm: POLLUTED water
      3. Lichen often killed by city pollution
        Grows in clean air
  3. Advantages to each method:
    1. Ind. Organisms:
      1. Long time period, cheap, no equipment
    2. Equipment:
      1. More accurate at any time
Sustainability
1. Conservation:
  1. Preserves food chains
  2. Keeps plants for medicines
  3. Recreational culture
  4. Whales
    1. Hunted for body parts
      1. Oils for alcohol, machinery
      2. Skin for belts, shoes, bags
    2. Kept in captivity for entertainment
    3. Controversy surrounding whaling bans
    4. Scientists want to dissect for anatomical info
      1. Need to be kept alive for migratory patterns
2. Sustainable Development:
  1. Taking enough while leaving some for future generations
  2. Fish quotas
  3. Tree replantations
  4. Endangered species are at risk

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Understanding our Environment

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	Creado por Oliver Wood hace casi 11 años