Fossils themselves, and the sedimentary rocks they are found in, are very difficult to date directly. Instead, other methods are used to work out a fossils age. These include radiometric dating of volcanic layers above or below the fossils or by comparisons to similar rocks and fossils of known ages.

How do paleontologists know how old dinosaurs are?

There are two ways to determine the age of a dinosaur fossil. One is called relative geologic time, which involves deciding whether one dinosaur fossil is older or younger than another. Geologists then measure the proportion of parent and daughter atoms present in the ash crystals to determine the crystals age.

Who is the first known human?

Homo habilis The First Humans One of the earliest known humans is Homo habilis, or “handy man,” who lived about 2.4 million to 1.4 million years ago in Eastern and Southern Africa.