Chapter 17 - Emergence of the Human Species

Notes for Understanding Evolution - Chapter 17

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or back to Chapter 16 or ahead to Chapter 18

General guide on these review questions here

Notes for Chapter 17: Emergence of Humans

Nature has made pdfs available of classic papers on human fossil discoveries, including the most recent Toumaï skull

These pdf-format first year human evolution - lecture notes from Leeds University are interesting to read with lots of fascinating historical details. I found them useful, so will list them here, and also will provide some links under the appropriate sections below. I could not figure out the author of these notes but they appear to be intentionally available.

1. Evolution of humans
2. Primate taxonomy
3. A human's unique features
4. Primate behavior
5. Fossil apes and early fossil humans
6. The genus Homo appears, Homo habilis
7. Homo erectus and H. sapiens - biochemical dating
8. Homo sapiens: Modern humans
9. Cautionary tale - Human races
10. Measuring heads

Introduction

RQUE17.1: The following is a quote from the introduction to Ch. 17:

There is almost universal unanimity that our closest relatives are apes. The line leading ultimately to humans diverged from the ape branch during Tertiary times.

Take the main points from the Ch. 13 web notes regarding birds and the paraphyletic grade "reptiles," as conventionally defined, and use these notes to develop a parallel cladistic criticism of the above statement about "apes." Note that in the reptile case, it was possible to rediagnose reptiles to be monophyletic, i.e., to include birds as a reptile subgroup. Another, separate, criticism might address whether the fossil record really is consistent with a ladder-like "ape branch" as implied here.

Source of Image

I. Primate Radiation (Primate links: 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9)

RQUE17.2: Compare the branching pattern of Fig. 17.1 with a more modern cladogram-based such as these 1 - 2 - 3 and summarize the main differences implied by the differences in branching order and the differences in naming schemes.

For a modern cladogram based approach to primate classification, click here (this will help with a quiz question).

II. Adaptive Radiation of Humans

III. Forerunners of the Great Apes

RQUE17.3: It might seem odd that, in the Miocene (ca. 20 MYBP), apes were a more diverse group in Africa than monkeys. The reverse is true today, but we are quite familiar with the apes that managed to survive. One early ape was Dryopithecus africanus (or Proconsul africanus). Describe why this primate is considered an ape, and briefly describe how it likely lived.

IV. Forerunners of the Hominidae

Links: 1 - 2 - 3 - 4

RQUE17.4: What evidence was initially emphasized to place Ramapithecus and Sivapithecus within Hominidae, and what living "great ape" are they currently considered most closely related to?

More details: According to this interesting pdf, these are now considered male and female individuals of an extremely sexually dimorphic species. Gigantopithecus, which the text does not mention, is another important younger (6.3 to 0.5 MYBP) Asian relative that was huge (10 feet tall, about 1200 lbs.) and probably a bamboo feeder analogous to a panda. Its teeth have been collected for centuries among other fossil bones and teeth in caves and sold as "dragon bones" in Chinese pharmacies. Its fossilized skeletons might also have been the source of yeti or sasquatch legends. It is conceivable that this likely peaceful herbivore went extinct at the hand of Homo erectus, with whom it lived for perhaps the last half million years of its existence.

V. Australopithecines: The First Hominids

...are also covered in this interesting pdf

See some of the fossils here or here or here in spinning 3D (requires Shockwave plugin)

This site has a current evolutionary tree of hominids

Nature article on new significant discovery of a 6 to 7 million year old human skull, the earliest known record of the human family

Between 6 and 7 million years old, this skull is the earliest known record of the human family. Discovered in Chad in Central Africa, the new find, nicknamed 'Toumaï', comes from the crucial yet little-known interval when the human lineage was becoming distinct from that of chimpanzees. Because of this, the new find will galvanize the field of human origins like no other in living memory - perhaps not since 1925, when Raymond Dart described the first 'ape-man', Australopithecus africanus, transforming our ideas about human origins forever. A lifetime later, Toumaï raises the stakes once again and the consequences cannot yet be guessed. Dart's classic paper was published in Nature, as have most of the milestones in human origins and evolution. To celebrate the new find, we are proud to offer free access to a selection of ten of the very best from Nature's archives, including Dart's classic paper. Click here for free access to these fascinating papers.

RQUE17.5: Briefly summarize the significance of the recently discovered Toumaï skull from Chad.

VI. Humans Emerge: Homo habilis

Excellent link to pdf on early members of genus Homo

VII. Gathering-Hunting Way of Life

VIII. Homo erectus: The Explorer

Excellent link to pdf on Homo erectus

IX. Evolution of Human Society

X. Emergence of Modern Humans

Excellent link to pdf on modern humans