Population growth & Pest control.

Why do they live in a population?
1. -Greater Chance of meeting
2. Work together to bring up the young
3. Protection from Predators
4. If disease, better adapted to changing environmet
What is a population growth?
1. A group of ORGANISMS of a single species interbreeding and occupying a particular area
Growth Phase
Environmental Resistance
1. It is all the factors which may limit the growth of a population
  1. Food Availability
  2. Parasitism
  3. Predators
  4. Disease
  5. Weather
  6. Competition
  7. Acculmination of toxic waste
  8. Factors affecting population size
    1. Density Dependent Factors
      1. Food
      2. Parasitism
      3. Accumination of toxic waste
      4. Disease
    2. Density Independent Factors
      1. Floods
      2. Fire
      3. Frost
2. Population Fluctuations
  1. Regulated by balance between PR and DR
  2. Fluctuations are small
Competition
1. Plants compete for...
  1. Water
  2. Space
  3. Nutrients
  4. Sunlight
2. Animals compete for
  1. Space
  2. Reproductive Partner
  3. Shelter
  4. Food
3. Intraspecific Competition
  1. Competition for resources between members of the same species
  2. It's also the best driving force behind natural selection
4. Interspecific competition
  1. Competition for resources i.e SUNLIGHT, WATER, SPACE, FOOD.
    1. It's between members of different species
  2. Generally one out competes the other
Pest Control
1. A pest is an organism which competes/ adversely affects a population or organisms
  1. That are of economic importance
2. What pests do?
  1. Feed on crops and animals
  2. Compete with crop organisms for resources
  3. Directly cause disease in crop organisms
  4. Spoil food when being transported/stored
3. Chemical Control
  1. It involves the use of
    1. Herbicides
    2. Fungicides
    3. Insecticides
  2. How can it be applied
    1. Spray
    2. Powder
    3. Smoked
    4. Animal food
  3. What is a pesticide?
    1. Poisonous chemical weed to control organisms
      1. Considered harmful to agriculture
        Or to an organism involved in disease transmission
  4. Advantages
    1. Doesn't require high level of skill
    2. very effective masses of control
    3. Pests eradicated quickly and cheaply
    4. Chemicals can be applied on a small scale
  5. Disadvantages
    1. Some pests could harm fish or birds
      1. Contamination of food
    2. Long term exposure is harmful to humans
    3. Pests become resistant to pesticide
    4. Eradication can cause resurgence
4. Biological Control
  1. Beneficial organisms are deployed against undesirable pest
    1. Pests act as food source for introduced organism
      1. Reduction in numbers of pest as eaten, keep numbers below economical damage threshold
        Pests not eradicated completely as there would be no food source
  2. Advantages
    1. No environmental contamination
    2. Usually highly specific to one pest
    3. used in glass house situations
    4. Provide long term control if population eqilibrium is reached
  3. Disadvantages
    1. very few successful examples
    2. biological control agents slow to build up in numbers
    3. High level of skill and research involved for success
    4. Detailed knowledge of life cycle of pesticide is required
Carbon Cycle
Nitrogen Cycle
1. How can humans improve the circulation of nitrogen
  1. Fixing atmospheric nitrogen artificially using chemical processes that convert to fertilisers
  2. Micro organisms can be used for making compost and silage
  3. Sewage disposal boosts organic nitrogen supplies
  4. Large amounts of animal waste from stock rearing used as manure

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Population growth & Pest control.

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	Created by paige-monaghan over 10 years ago