This lack of transitional fossils was acknowledged by Professor Steve Jones of University College, London, when he published an updated version of Darwin's Origin of Species in 1999. This is what he wrote:

The fossil record - in defiance of Darwin's whole idea of gradual change - often makes great leaps from one form to the next. Far from the display of intermediates to be expected from slow advance through natural selection many species appear without warning, persist in fixed form and disappear, leaving no descendants. Geology assuredly does not reveal any finely graduated organic chain, and this is the most obvious and gravest objection which can be urged against the theory of evolution.

So we can see that the fossils give us an important fact. That is that the fossil record does not contain the partly developed animals that the theory of evolution predicts.

Before we finish looking at the theory of evolution, let's look at some of the other facts that are used to support this theory.

Classification of animals

Another argument used to support the theory of evolution is comparative studies of modern animals, known as 'cladistics'. When you look at animals, you will see that certain animals look like other animals. And scientists have produced a classification system so that things that look like each other are classified as being similar.

For example, monkeys and humans both have arms and legs and five fingers and five toes, and therefore humans and monkeys are classified together.

As another example, horses and donkeys and zebras all look like each other, with minor variations. So scientists have looked at all the creatures around the world and classified them all in this way. However, we can't do any experiments, and there is no way of knowing how these observable facts came to be. The theory of evolution simply provides one possible explanation of how animals came to look like they do. A perfectly valid alternative explanation is that some intelligent power created them like that

Variations within species

Another argument that is used to support evolution is variation within species. When we look at dogs we can see different breeds of dogs. Human beings on a relatively small timescale can interbreed dogs and produce very different dogs. The argument is that, given enough time, these variations could produce new species.