Biology B4

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ECOLOGY IN THE LOCAL ENVIRONMENT

  • An ecosystem includes all living things and their surroundings
  • Where an organism lives is called its habitat
  • A community is made up of the organisms living there
  • A population is the number of a particular organism in a community
  • Native ecosystems have a wider biodiversity than artificial ecosystems
  • Zonation is the gradual change in species distribtion across a habitat
  • Population size = number in 1st sample x number in second sample / number in 2nd sample previously marked
  • Capture-recapture data assumes : 1) no deaths, immigration, emigration 2) identical sampling methods 3) survival rates not affected by marking organisms
  • The distribution of organisms can be mapped using a transect line and displayed as a kite diagram
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PHOTOSYNTHESIS

  • Photosynthesis is a two-stage process : 1) light energy splits water into oxygen gas and hydrogen ions 2) carbon dioxide gas combines with the hydrogen to make glucose and water
  • Isotope experiments showed that the oxygen comes from the water
  • Greek scientists (plants take minerals from the soil)
  • Van Helmont (plant growth needs more than minerals)
  • Priestley (plants produce oxygen)
  • Carbon dioxide, light and temperature are limiting factors in photosynthesis
  • 6CO2 + 6H2O = C6H12O6 + 6O2
  • Leaves are adapted for efficient photosynthesis - large surface area, thin, contain pigments, have vascular bundles and guard cells
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DIFFUSION & OSMOSIS

  • Diffusion is the net movement of particles from a high concentration to a low concentration
  • The rate of diffusion is increased by a shorter distance, a greater concentration gradient and a greater surface area
  • Transpiration is the evaporation and diffusion of water from leaves
  • Transpiration rate is increased by light intensity, temperature, air movement and a decrease in humidity
  • Osmosis is the net movement of water from a high to a low water concentration across a partially-permeable membrane
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MINERALS & FARMING

  • Plants require nitrates for cell growth, phosphates for respiration and growth, potassium for respiration and magnesium for photosynthesis
  • Organic farming uses animal manure, crop rotation, weeding and differing planting times
  • Biological control has advantages (no chemical pesticides) and disadvantages (introduced predator may become a pest)
  • Hydrophonics has advantages (better control of minerals and water) and disadvantages (lack of support)
  • Minerals are absorbed by active transport, which needs energy
  • Detritivores feed on dead and decaying material
  • Saprophytic fungi use extracellular digestion
  • Intensive food production improves the efficiency of energy transfer
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Joelpadi

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I love you <3 Thanks 

Joelpadi

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I love you <3 Thanks 

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