105. Basic principles of ecology. Human environment, human ecology.

From greek.doctor
  • Ecology is the study of interactions between organisms and the environment
  • Supra-individual organization levels in ecology
    • Populations – groups of individuals
    • Communities – interactions of populations which interact
    • Ecosystem – the sum of communities and the environment
  • The Gaia hypothesis = the biosphere (ecosystems) and the physical components of the Earth are closely integrated and form a complex interacting system
  • The tragedy of the commons
    • The tragedy of the commons is a situation where people act independently in a way which is good for them, but because everyone does that, it ends up being bad for everyone
    • Example
      • A shared, common (“the commons”) land is discovered
      • Many farmers want to exploit the new land and put cattle there
      • The carrying capacity of the new land is blown, and none of the farmers can use the land anymore
      • Because everyone wanted to exploit the land for themselves, nobody could exploit it
    • This is relevant in human population growth
  • The prisoner’s dilemma
    • The prisoner’s dilemma is a situation where two prisoners who are not allowed to communicate with each other are independently interrogated
    • If one of the prisoners betrays the other, the betraying prisoner will go free while the other serves a long sentence
    • If both prisoners betray the other, both prisoners will serve long sentences
    • If none of the prisoners betray each other, both prisoners will serve short sentences
    • The conclusion is that the action which is best for them both (not betraying) is not the same action which is best for them individually (betraying)
    • This is relevant in global climate change
      • All countries will benefit from preventing climate change in the long run, but no individual country wants to prevent it (due to cost)
  • Interactions among populations
    • Predation – one organism kills and eats another
    • Parasitism – a relationship between two organisms where one benefits at the expense of the other
    • Competition – populations compete against each other
    • Coexistence/symbiosis – populations coexist, sometimes by helping each other
  • Every ecosystem is made up of three components
    • Producers – organisms which create food from inorganic matter
    • Consumers – those who consume the food producers produce, directly or indirectly
    • Decomposers/reducers – break down waste and dead organisms
  • Meadows model
    • A model of human population growth
    • This model says that the world will eventually reach a point where natural resources aren’t enough to sustain the world, and the population will collapse
    • The model is continuously updated
  • Human ecology
    • Humans are consumers in the ecosystem, sitting on top of the food chain
    • We depend on producers and decomposers
    • Unique for humans; we can change the environment
      • Mining
      • Pollution
      • Mechanical and chemical degradation
      • Production of xenobiotics, like drugs
      • We remove natural environment and replace it with our artificial environment
    • Relevant questions regarding human ecology
      • Can the environment be transformed to carry the accelerated population growth?
      • Can the growth be decreased to meet the carrying capacity of the environment?
      • Can the ecosystems work normally under the present conditions?