We

We are all more closely related than you think. The traditional way to view how life developed on earth was via something called the Phylogenetic Tree (see image to the right), it's a fancy term for a branching system. The branches start at a root and then progress via various steps becoming more complicated as they go. The tree illustrates how all life was once one thing and progresses into being us, the most complex form of life on the planet.

But at a certain stage a clever monkey once asked "where did the root come from?". The chicken/egg issue has been found to be a false dichotomy. It is now known that life started from simple inorganic molecules, which interacted to make other molecules which could replicate themselves. After this it was just a matter of millions of years (a blink of an eye in earth's history) before more complicated organic replicants came to being.

Once the earliest life was created it took another 3.5 billion years for it to make us. Whilst the stepped classification is useful as it gives specific delineation for scientific study, in fact the process is much more fluid. Similar to the roots of a tree branching out, although many stems are produced it is still the same macro organism.