Characteristics of living things

Next time you’re outside, look around you. What do you notice? You might see cars driving by, or the grass by the road. Perhaps you hear birds chirping nearby. The world around you is a mix of different things — plants, animals, stones, clouds, and man-made things, such as cars.

If you were asked to identify which are living things, and which are non-living things, the answer would probably seem quite obvious — you just know if something is alive or not. But do you know what really makes something alive — what the characteristics of living things are? Scientists who study living things — biologists — have figured out that all things we consider living, share seven basic characteristics. What’s something you do every day to stay alive? You eat and drink!

Just as you need food, all other living things need to take in materials — nutrients — from their surroundings. All living things need nutrition. What is this nutrition used for? Well, the first thing nutrients are used for in cells is the process of respiration. Respiration is the process through which energy is released from food substances.

This energy is then used to power all kinds of different processes. One of them is growth. You are much bigger now than you were when you were born, and you will probably continue growing for some time. Maybe you’ll want to have children one day, too. Just like you, all living things have the ability to produce offspring — to reproduce.

The next thing all living things do, is move. Many animals, including humans, can get up and change location. But even plants move in their own way! Their movements are simply so slow that we can’t really see them. Movement is often a response by a living thing, to something it senses in its environment.

For instance, if you’re outside when it’s raining, you’ll probably try to move somewhere dry. If you’re inside and the heating is turned on, you might get too warm and have to take off your sweater. You, like all other living things, are able to sense what is happening around you and adapt to it. What a great feature to have! All these processes come at a cost, however.

The chemical reactions that occur in cells and make all these processes possible, create waste products. These waste products could poison the cells, so waste has to be removed. How do humans get rid of waste products? Well, we sweat, we pee and we poo! This removal of waste products is excretion, and all living things do it.

For something to be classified as a living thing, it needs to have all of these seven characteristics. For instance, although cars move, release gases and need “nutrition” in the form of fuel, cars don’t grow or reproduce, and aren’t sensitive to their environment. Cars, therefore, are non-living things. There are some exceptions. For example, if someone can’t have children — they can’t reproduce — it doesn’t suddenly mean they are not alive!

Still, the seven characteristics are a good guideline for biologists to separate living from non-living things. And make sure to look out for all the different kinds of living things when you’re outside. Who knows what you might find!