When looking at my photo reference, I thought that it would be a good idea to try and get an idea of what the different species would look like. In a lot of the diplays in the museums I visited, there were artworks which gave a general idea of the homanoids, behavior, and environment at the time.
Initially, to get an idea of where the muscles would be placed, and where the features would be more defined, I started with a skull and then added muscle, and eventually skin and hair. From that general i created several conepts for each stage of evolution.
Homo Ergaster/ Homo Erectus
When doing actual images for the gallery I do intend on doing sepourate images. These concepts don't really give enough of a feel for their social interactions, or their environment.