topic 4a: organism in the environment

Ecology is the branch of biology that studies these relationships and tries to make sense of them.


Key terms

  • Ecosystem: It is all of the living (biotic) organisms in an area and all the non-living (abiotic) conditions

  • Habitat: The place an organism lives

  • Population: All the organisms of one species in a habitat

  • Community: All the different species in a habitat


Biotic and abiotic factors

Biotic and abiotic factors will affect population sizes and distribution of species within ecosystems


Biotic:

  • Food availability

  • Predators

  • Competition from other organisms

  • Infection from pathogens


Abiotic:

  • Sunlight

  • Temperature

  • pH

  • Water

  • Minerals

  • Soil type

  • Salinity (salt levels)

  • Wind


Investigating population sizes

  • Ecologists work to study and monitor ecosystems

  • Part of this is monitoring population sizes and how they are distributed in the ecosystem

  • This can sometimes be very challenging

  • Therefore scientists use sampling techniques to get an estimation which is much quicker


  • Ecologists use a piece of apparatus called a quadrat to take samples

  • Quadrat is a square metal frame, usually one meter length (we use half) but will vary depending on where and what you are sampling