ecology wk1

• Populations


  Distinct group of individuals of the same species, in the same place and at the same time, capable of interacting and reproducing
• Population properties


  • Size
  • Density
  • Population structure (distribution of different aspects like age, sex)
• Population dynamics

  1. Growth rates

  2. Mortality rates

  3. Fecundity

  4. Immigration/emigration rates
• Cohorts

  Recognisable group within a population (based on age, size, weight)
• Metapopulations


  Subdivisions of a population that are spatially separated but still interact
• Community


  Assemblage of populations of different species in a given place and time
• Biosphere

  Part of Earth that contains all life, from deep ocean to upper atmosphere
• All major problems in biological sciences are ecological in nature: climate change, conservation, biodiversity losses, overpopulations, diseases, GM crops etc.
• Much evolution (NS) is driven by ecological processes – influences of competitors, predators, prey, climate, shelter, temperatures, diseases etc. may all be considered part of the ecology of an organism and / or population.
• We can examine ecology at the genetic level e.g., change in allele frequencies as a result of ecological factors such as virulent diseases.
• A single organism may have major influences on the ecology of an environment (e.g. blue whale, oak, first of a new parasite).
• An organism's birth, survival, growth, reproduction and death can all influence ecosystems.
• Populations have properties in a way that individuals or genes do not.
• Population structure may be influenced and altered by growth rates, mortality rates, fecundity, immigration/emigration rates.
• Metapopulations are subdivisions of a population, separated in some way (especially spatially) but which still interact.
• Metapopulations can be especially important when considering issues of fragmented habitats such as nature reserves or islands.
• Community structure and dynamics will vary with individual populations changing the overall community structure.
• Ecosystem is the largest scale typically examined, combining communities and abiotic aspects of the environment.
• The biosphere is the part of the Earth that contains all life, running from the deep ocean to the upper atmosphere.