Tag Archives: human_evolution

Hominoids, hominids and homonins – what’s the difference?

 

Image source

Primates: (Order Primate) includes all species with prehensile (grasping digits) with opposable thumbs. They also have forward facing eyes with binocular vision, a well-developed cerebral cortex and bicuspid teeth. This includes all the new world monkeys (such as spider monkeys) and old world monkeys (macaques), as well as the Greater and Lesser apes.

Hominoids: refers to the broad term for great and lesser apes which includes gibbons, orangutans, gorillas, chimpanzees and humans. They have no tail, an upright gait and arms shorter than their legs.

Hominids: includes just the great apes, orangutans, gorillas, chimpanzees and humans

Hominins: Refers to the bipedal human species and their relatives.  such as the following:

  • Sahelanthropus tchadensis (Tournai) – mix of human and chimp features, small brain, may have been bipedal (6.5 mya)
  • Ardipithecus ramidus – Primitive teeth, probably bipedal (4.5mya)
  • Australopithecus afarensis (Lucy) – Walked upright, about 1.2m – 1.4m tall , basic stone tools (3.5mya)
  • Homo habilis (Handy man) – More advanced stone tool making and use, brain size half of modern humans (2 mya)
  • Homo ergaster – Small face and teeth, advanced tool use and may have used fire (2.5mya)
  • Homo erectus (Java man) – Modern features, but with a visible brow ridge, brain size 60-70% of modern humans (1 mya)
  • Homo heidelbergensis – Found in Europe, brain size very similar to modern humans, advanced tool use (1 mya)
  • Homo neanderthalensis – Stocky, adapted to cold, tool use, social structures, rudimentary language possible, brain size slightly larger than modern humans. (500, 000 ya)
  • Homo floresiensis (the hobbit) is known from fossils discovered in Indonesia and co-existed with Homo sapiens. (17,000 – 95,000 ya)
  • Homo sapiens (including the sub-species Denisovans) (present day)

The Australian Museum has some good information about how the definitions for these terms have changed over time, causing lots of confusion for students and scientists alike. New technologies, such as CT scans and DNA analysis, have given us new evidence to support different theories of human evolution than from fossil morphology alone.

The Science of Human Evolution (YouTube, 54.42min) is an interesting video that describes the features of various human ancestors, based on their fossil remains.

Evolution from Ape to Man (YouTube, 50.43min) is another video that describes how the search for the “missing link” in human evolution was based on flawed thinking and how scientists have changed their theories depending on the evidence that becomes available.

Human face evolution in the last 600 million years (YouTube, 1.07min) shows an animated progression of facial features from our distant ancestors to the modern human face we recognize today.

Great Human Odyssey (YouTube, 1hr 52.06min) describes how human ancestors migrated out of Africa and developed skills, technology and talent to survive in almost every environment across the globe.

Modern humans may have interbred with Neanderthals and Denisovans (YouTube, 10.54min) – an excellent segment from Catalyst on ABC with the evidence that modern humans have DNA in common with neanderthals and Denisovans indicating that modern humans may have interbred with these species.

Human Evolution

evolution_silohettesImage source

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 

7 Strange and Surprising ways that humans have evolved recently