The photographs below show how a tree can change in nature throughout the year.

All living things undergo changes throughout their lives. Some of these changes are annual like those in the picture. This means they happen every year.  

Many other changes occur over much longer periods - think about the changes that occur in our bodies over our whole lifetime. Scientists refer to these changes as life cycles. 

Many life cycles are influenced by our environment and seasonal changes.

Let's take a closer look.