The Seven Characteristics of Life

You can remember what makes something alive using the handy acronym MRS GREN - and these seven features apply to every living thing on Earth, from your pet dog to the mould growing on old bread.

Movement means organisms can shift their position, either completely (like animals running) or partially (like plants growing towards sunlight). Respiration isn't just breathing - it's the crucial chemical reactions happening in every cell that break down nutrients like sugars to release energy for staying alive.

Sensitivity allows organisms to detect changes around them and respond accordingly - think of how you pull your hand away from something hot, or how plants lean towards windows. Growth means getting permanently bigger through an increase in size and dry mass (the weight left after removing all water from an organism).

The remaining characteristics keep life continuing and functioning properly. Reproduction creates more organisms of the same species, while excretion removes waste products and excess substances that could harm the organism. Nutrition involves taking in materials needed for energy and development - whether that's eating food like animals do, or absorbing nutrients from surroundings like fungi.

Quick Check: All living organisms contain at least one cell, but remember - viruses are considered organisms yet aren't technically "living" because they can't carry out these processes independently!