- Biosphere – the part of planet Earth that accomodates living organisms.
- Ecosystem – an interactive whole consisting of living organisms (plants, animals, etc) and their non-living environment (water, rocks, etc).
- Organism community – all the populations of living organisms inhabiting a specific area.
- Population – all the individuals of the same species living in a specific area.
- Species – the basic unit of the classification of living organisms; e.g. spruce, bear.
- Organism – a living being; bacteria, protist, plant, fungus, or animal.
