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11.28: Human Evolution

Difficulty Level: Basic Created by: CK-12
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What is a "cave man"?

What if you were to wake up with a group of Neanderthals? They were close relatives to modern humans. Still you might find them to be a bit different from your usual friends.

Human Evolution

Humans evolved during the later Cenozoic. New fossil discoveries continue to alter the details of what we know about human evolution. The major evolutionary events are well understood though.

Primate Ancestors

Humans evolved from primates, but humans did not evolve from apes. Apes and humans have a primate common ancestor. About 7 million years ago, chimpanzees (our closest living relatives) and humans shared their last common ancestor.

Hominids

Animals of the genus Ardipithecus lived roughly 4 to 6 million years ago. These animals had brains roughly the size of a female chimp. Although they lived in trees, they were bipedal. That is they could stand on two feet. What are the advantages to being bipedal? An organism that can stand up can see farther. This is important if you live in a grassland. A bipedal organism uses its hands and arms for hunting.

Another human ancestor Australopithecus afarensis lived between 3.9 and 2.9 million years ago. These animals were completely bipedal. Their brains grew rapidly across the generations ( Figure below ).

Australopithecus afarensis is a human ancestor that lived about 3 million years ago.

Homo

The genus Homo appeared about 2.5 million years ago. These human-like primates developed the first stone tools. Homo erectus evolved in Africa about 1.8 million years ago. Fossils of these animals show a much more human-like body structure. This allowed them to travel long distances to hunt. Cultures began and evolved.

Homo sapiens

Homo sapiens is our species. We originated about 200,000 years ago in Africa. Evidence of a spiritual life appears about 32,000 years ago. The evidence includes stone figurines that probably have religious significance ( Figure below ).

Stone figurines likely indicate a spiritual life.

The ice ages allowed humans to migrate. During the ice ages, water was frozen in glaciers. Land bridges such as the Bering Strait allowed humans to walk from the Old World to the New World.

Summary

  • Australopithecus afarensis was completely bipedal and had a growing brain.
  • Homo erectus evolved 1.8 million years ago. These organisms left behind signs of an early culture.
  • Our species is Homo sapiens . We evolved 200,000 years ago in Africa and spread.

Practice

Use this resource to answer the questions that follow.

Human Evolution Made Easy at http://www.youtube.com/watch?v=u7Y34zrJjtk (9:39)

  1. What was Darwin's little heresy?
  2. Who was Huxley?
  3. Where was the first Neanderthal found?
  4. What was the problem with the fossil evidence from Africa?
  5. List the traits that separate humans from apes?
  6. What did DNA indicate?
  7. What does mitochondrial RNA indicate?

Review

  1. Why is being bipedal a good thing?
  2. Did humans evolve from apes? Explain.
  3. What makes Homo sapiens different from Homo erectus ?

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Difficulty Level:

Basic

Grades:

6 , 7

Date Created:

Jan 04, 2013

Last Modified:

Jun 16, 2014
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