We can easily name the living and non-living things around us, but it is difficult to define life. Instead, biologists describe the activities and properties that characterize living things.
Living and non-living things
A living organism shows a high degree of organization. Millions of atoms and molecules are arranged in an orderly and complex way to produce a living organism composed of one cell or many cells. This needs a lot of energy. Also, a constant supply of energy is needed to maintain a living organism. Thus, obtaining and using energy are important activities of living organisms.
All living organisms share several key characteristics or functions: Nutrition, respiration, excretion, movement, sensitivity, growth, reproduction. When viewed together, these characteristics serve to define life.
Non living things such as oxygen (gas) water (liquid) and stone (solid) do not show a high degree of organization. Their energy content is comparatively low. Other examples of non-living things include fuel, gas, chair etc.
There used to be a confusion on whether the number is 7, 8, 9 or probably 10. Whatever be the number, as long as the characteristics and features listed are seen in all living things, then its correct. For your consumption, we have compiled the 10 characteristics of living things.
Ten characteristics of living things
All living things carry out several chemical processes to produce and utilize energy
All living things are made up of one or more cells.
A living organism needs to stay alive. It uses food to build up its body and provide energy for its various activities. Generally, animals obtain ready-made food from their surroundings; plants make their own food using simple inorganic substances and the sun’s energy. Taking in (feeding) and using it is known as nutrition.
A living organism respires, i.e. releases energy from the breakdown of substances within its body. This process usually needs oxygen which the organism must get from its environment while carbon dioxide is given out as a waste product. The energy released enables the organism to carry out its life processes and maintain its complex body organization.
Activities within the body of a living organism produce unwanted and often toxic substances known as wastes. The organism removes or excretes these wastes from its body.
A living organism is able to move whole its whole body or part of its body. Generally, most animals can move themselves from one place to the another, while plants move only part of their bodies in response to stimuli.
A living organism is sensitive, ie. It is able to detect and respond to changes in its surroundings and within itself. Such changes are known as stimuli. Pain caused by a pin prick and changes in temperature and light intensity are examples of stimuli.
A living organism grows. This is an increase in size which is usually accompanied by development (a change in form and abilities).
All living organisms reproduce, i.e. produce individuals (offspring) resembling themselves.
Through this process, a particular of organism lives from generation to generation.
A living organism carries out all the above processes. When these processes cease, it dies.
Non-living things may carry out one or two of the above processes but not all of them. For example, a crystal grows by deposition of new materials from the surroundings on its outer surfaces. This however, is different from the various process that occurs in a living organism where new materials are formed within the organism’s body.
All living things are organized. To make the point clearer, living things are organized into similar parts. organelles come together to form cells, cells come together to form tissues, tissues come together to form organs, organs come together to form systems then systems come together to form a full living thing.
M – Movement
R – Reproduction
S – Sensitivity
M – Metabolism
C – Cellular Composition
N – Nutrition
E – Excretion
R – Respiration
G – Growth
O – Organization