Cambridge IGCSE Biology (0610)

1.1 Characteristics of living organisms

Living organisms share a set of characteristics that distinguish them from non-living things.

The seven characteristics of living organisms

Most biologists recognise these seven characteristics, often remembered by the acronym MRS GREN:

• Movement — An action by an organism causing a change of position or place
• Respiration — Chemical reactions that break down nutrient molecules to release energy
• Sensitivity — The ability to detect and respond to stimuli
• Growth — A permanent increase in size and dry mass
• Reproduction — Processes that make more of the same kind of organism
• Excretion — Removal of toxic materials and waste products of metabolism
• Nutrition — Taking in of materials for energy, growth and development

Important notes

• All living organisms show these characteristics at some stage of their life.
• Some non-living things may appear to show one or two of these features, but not the full set.