Course of human evolution

Describe the course of human evolution from that of the early vertebrates

to the emergence of humankind.  Discuss the impact that both natural selection and fitness have had on each step of this evolutionary journey

Homo Sapiens Neanderthalensis

The Homo Erectus evolved into Homo Sapiens. During evolution, two sub-species of Homo Sapiens were identified- Homo sapien Neanderthal and Homo sapiens sapiens. The cranial capacity of Neanderthal grew from 1200 to 1600 cc. Some small hand axes had also been discovered.