7 Signs of Life
The 7 signs of life indicate what is non-living and what is living.
If a particular thing has all of these charateristics/signs, it is a living thing.
Here are the 7 signs of Life:
Movement:
Moving around. Humans run, bacteria propel themselves with flagellum, plants grow outwards and/or move towards the sun...these are all movement.
Respiration:
The basic metabolism reaction that releases energy for animals.
Sensitivity:
To detect and/or react to changes or its surroundings. Humans show emotion, animals growl, plants move towards the sun and detects the temperature.
Growth:
Our cells multiply as we become bigger or become more sophisticated and mature.
Reproduction:
Living things produces offsprings, which can be accomplished by a variety of different ways. For some it can asexual, for example splitting itself (fission) or spreading pollen; it can also be sexual, which is what most animals do. (Yes, for humans it's sexual intercourse.)
Excretion:
Removing ways from the body. That includes sweat, urine, poo and other things like that that carry the organism's unwanted materials.
Nutrition:
All living things take in food and use it for energy or for other purposes.
All these form a handy acronym: MRS GREN.
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Distinguishing between living and non-living things:
A motorcycle moves, eats petrol, and excretes carbon monoxide through the exhaust pipe. However, since it does not make baby cars (that would be so awesome for car dealers) and does not grow, cars are not living things. Some people ask are viruses living things. For scientists, viruses are still in the grey zone because although they cannot reproduce by themselves, they can by hijacking a host cell. Thus, because of this and other factors, viruses are considered "half-living". But you don't have to worry 'bout that because such questions won't appear on exams. Questions? Email me! (Box below)
