Living things are adapted to their habitats. This means that they have special features that help them to survive.
An African elephant, for example, lives in a hot habitat and has very large ears that it flaps to keep cool.
A polar bear, on the other hand, lives in a cold habitat and has thick fur to keep warm.
It’s not just animals that are adapted to their environment, plants are too. A cactus is well adapted for survival in the desert. They have long roots to collect water from a large area and a stem that can store water for a long period of time.
The animals and plants in one habitat are suited to live there and may not be able to survive in other habitats. When a habitat changes, the animals and plants that live there are affected.
The spines of a cactus are much better than flat leaves at preventing water being lost from the plant. The spines are also good protection from animals that might want to eat them.
When living things reproduce they pass on characteristics to their offspring. This is known as inheritance.
You’ve probably noticed that you might look like your parents. This is because you inherit key characteristics from them, like your eye colour, skin colour and height.
All living things produce offspring of the same kind, but normally offspring are not identical to their parents; there are variations that make them different.
For example, if you cross two different breeds of dog, you get a dog with a combination of characteristics. Some characteristics come from their mother and some from their father.
However, you don't inherit everything from your parents. For example things like hairstyle, scars and ear piercings.
Evolution is the way that living things change over time.
The first person who explained how evolution happens was Charles Darwin with his scientific theory of natural selection.
Charles Darwin observed that although individuals in a species shared similarities, they were not exact copies of each other; there were small differences or variations between them. He also noticed that everything in the natural world was in competition.
The winners were those that had characteristics which made them better adapted for survival. For example, they were stronger, faster, cleverer or more attractive than others in their species. These living things were more likely to reproduce and pass on their useful characteristics to their offspring.
Individuals that were poorly adapted were less likely to survive and their characteristics were not as likely to be inherited.
Over time, the characteristics that help survival become more common and a species gradually changes. Given enough time, these small changes can add up to the extent that a new species altogether can evolve.
Charles Darwin published his scientific theory of natural selection in a book called ‘On the Origin of Species’ in 1859.
Darwin’s theory explained how every living thing is connected in a family tree that stretches back billions of years to the beginning of life on Earth.