Dawkins talks of how different species are related to one another. A species is not evolved into another but related by sharing an ancestor. If you lined up female rabbits from daughter to mother to grandmother and so forth down the line for many years, then walked the line backwards you can start to see the changes the rabbits have made genetically through time. However the change is very small and hard to see normally unless you were looking for it. He was describing how rabbits are related to leopards by walking backwards down the line of rabbits to what he calls the hairpin. Then you would turn at the hairpin and walk forward to the leopard. The hairpin is the ancestors that start to look less and less of the rabbit and start to look like the leopard, again these changes are small through time and are hard to really notice. Dawkins says that all animals are related to one another in this sharing of the ancestor whether it is a porcupine to a dolphin or a human to a haddock by means of an evolutionary history. We choose in the walk from the hairpin to the leopard to not walk down other paths since it will lead us to other species. This is because the hairpin animal is evolution to countless other end points.
It has been proven that domestic dogs today are modified wolves; this was determined by molecular genetic evidence in which they found that domestic dogs have wolf ancestry in them. Humans breed dogs to maintain certain breeds and to make sure that there is no interbreeding happening since this is the worst thing to happen in the book of the pedigree breeder. Dawkins says that breeders are sculptors since they choose what gene they want for the look of the breed that they want to make. Their chisel may not carve flesh but it is chiseled out of the gene pool and replaced by genes for the modification the breeder chooses. Also there is hybridization, and this is where they breed two different breeds of dogs to make a new one. Dawkins feels that the relevance to natural evolution, even when a human is the selecting agent, the process is exactly the same. See any one can understand evolution through artificial selection. Natural selection is the same thing but it just has one minor detail that is different or changed. When there is a systematic increase or decrease in a particular gene pool we refer that to being evolution.