Evolution means change over time. In the biological sense, evolution means change in DNA over time.
There is much that we know about biological evolution. The tree of life at the right is based on information from DNA sequence comparisons of living creatures. This data shows that all living things, from microbes to man, are related. All living creatures (top) have descended from a common ancestor (bottom of diagram). We also know that gene transfer (indicated by crossed lines) is an important mechanism for evolution.
To find out more about the evidence for evolution, click here.
To find out more about how evolution happens, click here.