Evolution is the gradual development and change of heritable traits in populations over successive generations. It is a long process that brings about biodiversity - from a single bacterium to a spectrum of plants and animals, all thanks to evolution!
There are many different types of evidence that support the theory of evolution. Some were perceived and noted by Charles Darwin in the 1800s, and some were added later when modern biochemical technologies became available. For the DAT, we will need to know the following 5 lines of evidence: fossils, biogeographical, embryological, comparative anatomy, and biochemical.
The study of fossils is also called paleontology. Fossils reveal a lot of information about prehistoric living organisms, including anatomy, lineage, behavior, habitat, etc.
There are two types of fossils — one is fossils of the actual remains of the animal, another one is fossils of their traces (ichnofossils), which records details like footprints and nests.
You may also wonder, how do fleshy living organisms turn into solid rocks? This can be achieved through the process of petrification. As the body of a living organism becomes buried under layers of sediments, minerals slowly seep into its body and replaces organic materials, hardening the corpse.