Human evolution began in Africa six million years ago, it describes the process our ancestors followed to eventually become the modern humans we are today 'today. Major changes in human evolution resulted in the appearance and development of modern Homo sapiens. These major changes concern the shape of the skull, the size of the brain and the size of the snout. This research essay will describe and evaluate these changes to describe and explain how modern humans evolved. Natural selection plays a major role in human development over time. Natural selection is Darwin's most famous theory; it states that evolutionary change results from the production of variation in each generation and the differential survival of individuals with different combinations of these variable traits (Natural Selection, 2009). Brain size Environmental conditions have spurred important developments in how we became who we are today. The development of early humans faced environmental changes and evolved larger bodies, larger and more complex brains. Having a larger, more complex brain was an advantage. Processing and storing a lot of information became easier, which gave early humans the advantage of interacting more socially and becoming aware of encounters with an unfamiliar habitat (Bigger Brains: Complex Brains for a Complex World, 2015 ). From two million to 800,000 years ago Brain and body size have increased dramatically in an era of climate change. At that time, having large and complex brains gave humans the advantage of interacting with each other and their environment in different ways. Homo erectus is the oldest known human to have possessed modern human body proportions. The average brain size of Homo erectus is estimated... middle of paper ... which is why the mutation is observed in every human being on this planet. When the jaw muscles weakened, this allowed the head muscles to grow, which made room in the skull for a larger brain. The image on the right shows that the chimpanzee skull is much smaller because it has a larger jaw to support, while the human skull is larger because the jaw is smaller. This gave the skull more space for the front of the brain to expand. The prefrontal cortex (the largest part of the brain) gave humans an advantage, making them smarter. Give them the opportunity to learn to talk and plan for the future. The development of our ancestors over time led us to become the complex, modern humans we are today. Our species' ability to create new realities in our minds that allow us to perceive things that evil primates were never able to do.