Mr. Scanlon's Biology Class

Human Evolution

  1. Objectives
    1. Students will compare and contrast the physical characteristics of both Primates and Humans.
    2. Students will write an essay explaining why three human characteristics are significant.
    3. Students will learn why "Lucy" is significant for human evolution.

    Assessments

    1. Objectives 1 and 2, assessment of activity 1 can be made by the evaluation of the student essays.
    2. Objective 3, assessment of "Lucy" can be made by the evaluation of the student answers to activity 2.

Human Evolution

Introduction

Evolution is a theory that states; over time things change. Nature has produced ways that cause the genetic makeup of creatures to vary. Some of these variations give a creature an advantage over others, allowing him to survive better and have more offspring. These genes are good genes and are passed on more than others. Other less adaptive variations tend to be expressed less frequently. It is the buildup of these good variations that causes a population to change over time. Even though we can identify these changes in many species, it is hard to believe that we (humans) have gone through this same process.

Primate Characteristics

There are a number of different animals that fall into the order primate. Chimpanzees, Gorillas, and Orangutans are just a few. Well, we are also primates. But, do you know why we are considered primates? All primates have the following characteristics.

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Human Characteristics

Many people do not like to think of us as primates. People like to should how different we are from the other primates. It is the physical differences that make us unique. But, do you know what some of these differences are? The following list will describe some of the major differences.

I. Brain Size: Our brain size averages 1,350 cm3, whereas a chimpanzees’ is only about 350 cm3.

I. Straight Face: Our nose and mouth are almost straight down from our eyes, whereas that of other primates jut out.

III. Small Jaw and Teeth: Even though we have the same number of teeth as chimpanzees, their teeth are much larger.

IV. Foramen Magnum: This is the opening at the base of the Cranium that the spinal cord comes out of. It is directly underneath the skull, which shows we are built for upright walking. The foreman magnum of other primates is moved further towards the back of the skull.

V. Curved Spine: Our spine is curved which helps us walk upright. Other primates have straight spines.

VI. Short Arms/Long Legs: There is a ratio between the sizes of the arms compared to the legs. A gorilla’s arms are much longer than his legs, whereas our arms are shorter than our legs.

VII. Big Toes: We are the only primate who has his big toes in line (going the same way) with the other toes. The other primates have opposable big toes.

Activity 1

Now it is time to answer a question!

Pick out three human characteristics you believe to be the most significant and submit to me a short (one page) essay explaining why.

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Ancestors

Activity 2

Many scientist believe the link between apes and humans was a genus named Australopithecus. Australopithecus lived between 3 and 5 million years ago. Now you need to learn more about these creatures by reading about Lucy. I want you to go to the following site and read the article on Lucy. As you do, please answer the following questions.

  1. Where was Lucy found and by whom?
  2. How do we know Lucy is more like us than other primates?
  3. Do we believe Lucy was killed by another animal for food?
  4. What method of dating was used to determine how old Lucy is?

Homo habilis

Homo habilis was the first primate to have enough physical characteristics to be put into our genus of Homo. He appeared about 2 million years ago. His brain size was only 500 to 700 ccm. He was the first to make tools.

Homo erectus

Homo erectus showed up about 1.5 million years ago. His brain capacity was 800 cm3. You may know him under some different names, Java man, or Peking man. He made much more refined tools than H. habilis. They were the first to use fire. It was H. erectus that appears to have moved out of Africa into Eurasia.

Neanderthals: Homo sapiens

Neanderthals showed up about 230,000 years ago and were around up to about 30,000 years ago. They lived in Europe, East and Central Asia. Even though the skulls were much thicker than ours today, their brain size was larger, 1,500 cm3.We have found evidence of Neanderthals that buried their dead.

Modern Man: Homo sapien sapien

You may know him as Cro-Magnon man because he was originally found in a cave near Cro-Magnon, France. Gone was the heavy thick boned skull, protruding brow ridge, slanting forehead and coarse thick jaw. He appeared about 40,000 years ago. Between 10,000 to 20,000 years ago he produced the famous cave drawings. He was a hunter and gatherer. At some point not too long ago he began to domesticate plants and animals.

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Related Sites

Fossil Hominids

Human Prehistory

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Contact Information
Edward Scanlon
Site last updated: March 20, 2001