One of the earliest defining human traits, bipedalism — the ability to walk on two legs — evolved over 4 million years ago. Other important human characteristics — such as a large and complex brain, the ability to make and use tools, and the capacity for language — developed more recently. Many advanced traits — including complex symbolic expression, art, and elaborate cultural diversity — emerged mainly during the past 100,000 years.
Since Darwin first proposed that humans and apes had a common ancestor, our understanding of human evolution has improved due to fossil finds, analysis of our closest living and extinct relatives, studies of geographic distribution and DNA analysis. Although the image above is often used to represent human evolution, the process is not the simple linear procession that is shown. Your task is to write an essay of at least eight paragraphs that explains why this image is suitable, but also why it is an inaccurate representation of human evolution.
- Introduction – what will the following paragraphs explain?
- Outline primate family tree, including lemurs, monkeys, apes, hominins and Homo sapiens.
- Where do Australopithecus sp., Homo erectus, Homo habilis, Homo neanderthalensis and Homo heidelbergensis fit in?
- Discuss bipedalism – location of foramen magnum, shape of spine and ratio of arm to body length.
- Discuss skull shape, brow ridges, sagittal and nuchal crests, prognathous jaw and facial sloping.
- Discuss cranial capacity and relationship to body mass and intelligence.
- What is the evidence that human evolution is not a linear progression, but a many-branched family tree?
- Conclusion – what are the main characteristics that can be identified in the image and why is the image an inaccurate representation of human evolution.
Introduction to Human Evolution from the Smithsonian