Characteristics of Living Organisms
All living organisms—whether plants or animals, single-celled or multicellular—show seven basic characteristics. These can be remembered using the mnemonic MRS GREN.
M – Movement
Movement is an action by an organism or part of an organism.
It causes a change in position or place.
Example: humans walking, plants bending towards light.
R – Respiration
Respiration is the chemical reactions inside cells.
It breaks down nutrients to release energy.
This energy is used for all life processes (metabolism).
S – Sensitivity
Sensitivity is the ability to detect and respond to changes.
Changes may be internal or external.
Example: pulling your hand away from something hot.
G – Growth
Growth is a permanent increase in size and dry mass.
It happens due to cell division and cell enlargement.
R – Reproduction
Reproduction is the process of making more of the same kind of organism.
It helps in the continuation of a species.
Can be sexual or asexual.
E – Excretion
Excretion is the removal of waste products of metabolism.
Also removes excess substances not needed by the body.
Example: carbon dioxide, urea.
N – Nutrition
Nutrition is the taking in of materials.
These materials provide:
Energy
Growth
Development
Example: plants photosynthesise, animals eat food.