Human to drier conditions. About 2.7 to 1

Human evolution is a theory that states that humans evolved from primates millions of years ago, evolution in humans has been happening for about eight million years and helped shaped what we look like today. There are many factors that can prove that evolution was the correct theory. One factor was that global cooling forced African rainforests to shrink and turn into savannahs, global cooling led to another factor that caused our ancestors to become ground dwelling animals and walk upright. When our ancestors started to walk bi-pedally, amazingly this caused an explosion in our ancestor’s intelligence and contributed to our evolution.

Evolution proves that all of our closest ape relatives evolved from one single species because all primates (including humans) became what they are because of natural selection and mutation. The transformation of the human diet since the discovery fires has hugely played a part of human evolution, when our ancestors discovered fire as well as its ability’s it not only allowed them to eat meat and vegetables more easily, but it also created a cultural advancement. Evolution affected early hominids intelligence to advance because of the creation of tools that were made by early humans to become more complex and creative.

The strategy of making stone tools changed various times in early human history. Over the course of millions of year’s evolution has moulded us and turn us into the most successful animal on earth physically. Climate change has a huge effect on the physical evolution of our ancestors, when the environment changed it forced our earliest ancestors to start living on the ground because of the degrading of their habitat. Old ocean fossil records from the Great Rift Valley located in East Africa show that the area was changing to drier conditions.

About 2.7 to 1 million years ago there were unusual wet and dry periods, this may have caused early hominids populations to adapt and readapt to the fast changing environment. The long dryer periods caused extreme famines in Easter Africa around 7 million years ago, the author of science weekly calls these unusual dry periods “mega droughts” that occurred 135,000, 75,000 years ago in the Great Rift Valley. Many plants and animals died from dehydration during this period, this forced our ancestors adapt or die like the other animals from this “mega drought”.

This caused our ancestors to migrate out of Africa and populate the rest world. They moved to other environments because they could adapt, also since there was more food and a better chance of survival in other environments. 6 million years ago our earliest primate relatives walked upright to adapt to its fast changing habitat. Moreover, evolutionary changes to the body such as the thigh bone transformed our early human ancestors. None of our primate cousins can walk on two feet because their thigh bones are not developed like as our ancestors stood, it separated our direct ancestors from our cousin’s primates.

It began with our oldest direct hominine ancestor Orrorin tugensensis; the first bipedal hominine. Walking upright gave our ancestors more time for other uses with their hands. Bipedalism let early humans have more use with their hand and help our ancestors create tools. Evolution shows that as early humans became more bipedal they became craftier with their hands. Over the time of evolution our human ancestors advanced and could run on two feet faster, thus they lost their old climbing way of life. If one goes back two hundred generations in our family tree our oldest and closest direct relative would be an Australopithecus apheresis.