The eight characteristics of life

There are eight life characteristics that most living organisms will show at some time during their lives.

Movement: In all living cells, structure in the cytoplasm move. In more complex organisms, the whole structure may move. animals may move their entire bodies; plants may move parts of their body in response to external stimuli such as light.

Respiration: This is a series of reactions that take place in living cells to release energy from nutrients. This energy is used for all the chemical reactions that keep the body alive.

Sensitivity: Living organisms are able to detect and respond to changes in their external and internal conditions.

Homeostasis: This is the control of the internal conditions, to provide the best conditions inside cells for all the reactions needed for life to exist. For example, when we eat and drink we take in water - our body controls how much water is absorbed and removed from the blood, so that cell processes can continue to work efficiently.

Growth: This is the permanent increase in size and/or dry mass (mass without water content) of cells or the whole body of an organism. Your mass changes thourghout the day, depending on how much you eat and drink, but you growth is the amout by which your body increases in size when you take nutrients into cells to increase their number and size.

Reproduction: This includes all the processes that result in making more individuals of that kind of organism, such as making gametes and the fertilisation of those gamemes.

Excretion: Living cells produce many products from the reactions that take place inside them. Some of these are waste products - materials that the body does not use. For example, animals cannot use the carbon dioxide produced during respiration. Waste products may also be toxic, so they must be removed from the body by excetion.

Nutrition: The taking of nutrients, such as organic substances and mineral ions, into the body. Nutrients are the raw materials that cells need to release energy and to make more cells.

An easy way to remember all eight characteristics is to take the first letter from each process. This spells MRS H GREN.