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Grades K-2
Bipedalism means walking upright on two legs. For most of your students that probably comes easy, but for the earliest hominids, that sure wasn't the case! In this lesson, students will be introduced to Zeresenay "Zeray" Alemseged, a National Geographic Emerging Explorer , who is a paleoanthropologist. Students will be introduced to the complexities of this career while focusing on what bipedalism is and why it is an important characteristic of human development.
Connections to the Curriculum:
Geography, social studies, science
Connections to the National Geography Standards:
Standard 6: "How culture and experience influence people’s perceptions of places and regions"
Standard 17: "How to apply geography to interpret the past"
One to two hours

Materials Required:
Students will
  • learn about the life and work of Zeray Alemseged;
  • explain how Alemseged's cultural and life experiences influenced his career choice and locations of study;
  • explore different aspects of paleoanthropology through online resources including an interactive documentary;
  • describe the ways in which bipedalism is thought to have developed in hominids and, in turn, how bipedalism influenced the development of hominids; and
  • identify relationships between various aspects of human development and how learning about one aspect can help us understand another.
Geographic Skills:

Acquiring Geographic Information
Organizing Geographic Information
Analyzing Geographic Information

S u g g e s t e d   P r o c e d u r e
Write the phonetic spelling of the words paleoanthropology (pA-lE-O-an-thruh-PAH-luh-jE) and hominid (hAH muh nid) on the board and help students pronounce the term. Explain to students that paleoanthropology means the study of early humans, and hominid is the common name of humans and their ancestors. Tell students that many scientists all over the world have been working for years to better understand how humans developed and became the social, intelligent, cooperative beings that we are today.

Introduce students to Zeray Alemseged by showing them the online profile of his life and work and summarizing its contents for them. Explain that Alemseged is from Ethiopia, a country located on the continent of Africa, and that he now lives in Germany, a country located on the continent of Europe. Show students where these countries are on a globe or world map, and point out the location of your home state in the country of the United States of America on the continent of North America. For printable outline maps of the world, continents, and countries, visit the Xpeditions Atlas .

Explain that Alemseged is one of many people studying the early development of humans, and that one of the ways we can learn about people and animals who lived a very long time ago is by finding, digging up, and studying their bones (fossils) and remnants of objects buried with them. Africa, and especially Alemseged’s homeland of Ethiopia, is one of the best places to find fossils of early humans and their ancestors. For more information on human fossils in Africa, visit National Geographic's Xpeditions Hall 17: The Dig and related lesson plan, The Dig: Them Bones . For more information on why Africa was a good place for humans to develop, visit National Geographic: Outpost , click "In Search of Human Origins," then "Interpretation Station," then "Africa: Evolution Headquarters."

Explain that most of the scientists studying the early development of humans have traced human form back to what they consider a form very similar to apes and gorillas. Humans evolved beyond these animals by developing language, culture, society, and technology, but before that grand evolution, we were very similar to these creatures.

Activity 1:
Ask students to name similarities and differences between humans and apes. Write their answers on the board.

One of the differences students may note is that humans walk on two legs and apes use all four of their limbs. This four-limb locomotion is referred to as "knuckle walking." Tell students that is the change in hominid from knuckle walking to bipedalism that is seen by a great many scientists as the point at which the split between apes and humans happened. Tell students that today they'll be learning a little about how and why bipedalism developed.

Activity 2:
Divide the class into groups of four or five students. Then, create a miniature class obstacle course by doing the following:

  • Move six desks into two parallel rows of three, leaving space of about 12 inches between the rows.
  • Place five books at varying locations on the floor around the room.
  • Place one book on a shelf that is at your eye level.
Using a stopwatch, have student groups take turns running a relay race. Each team member must pass through the desk "alley," retrieve one of the books, return through the alley, and place it on the desk closest to the starting line. The last person on the team must retrieve two books—one from the floor and the one on the bookshelf—placing both books on the pile.

The trick? Students have to move around the room on all four of their limbs, rather than on two feet. Students may use their hands together only when they are stationary, and may carry things with only one hand, using the other one to help them move.

Record team times on the board.

Activity 3:
After all groups have competed against the clock, bring the class together for a discussion of the challenges they faced. Ask, what were the hard parts about your race? How could it have been easier? What was different about the book up on the shelf?

Accept all reasonable answers. Students are likely to say that keeping their hands on the floor slowed them down and made it difficult to maneuver and reach the higher books.

Ask students what else they use their hands for on a regular basis. Answers should include mention of the use of tools (e.g., hair and tooth brush, pencils, sports equipment), making gestures (e.g., waving, shaking hands with someone, even fighting), eating, playing instruments, and reaching for items.

Ask students if they have ever seen gorillas or apes either live or on television. Ask what similarities they've noticed between these animals and humans. Allow students to share their experiences.

Explain that while these animals use their arms for walking, they also use them for some of the same activities that people do. They use branches as tools, they wave their arms at each other, and they fight. Point out that these similarities are some of the reasons scientists think that humans and other primates share a common ancestor in the distant past.

Activity 4:
Tell students another reason that scientists believe there is a connection is the way in which human skeletons and ape skeletons are alike and different. Scientists have combined their efforts to determine where and when some small but key changes to human skeletons occurred in time. Have students visit Becoming Human ( Macromedia Flash Player required); this activity works best in Internet Explorer) and go to the "Learning Center" to complete the "Building Bodies" interactive activity. If feasible, use a projection device to complete this activity as a whole class, with one student at a time moving the bones into place. Each time related sections of the skeletons are put in place (e.g., both pelvic bones; both sets of legs), read aloud and explain the information presented in "Did You Know?"

Have students work in groups to create posters or murals illustrating the similarities and differences between apes and humans, and the benefits of bipedalism. Posters should include labels and short facts/descriptions of the differences and similarities discussed in the lesson.
Suggested Student Assessment:
Student presentations and displays should reflect an understanding of the ways in which bipedalism may have developed, and its impact on the evolution of humans.
Extending the Lesson:
  • Have students visit the National Geographic: Outpost feature and try some of the activities for grades K-4 .

  • Have students visit the American Museum of Natural History's Ology site and explore the sections on Archaeology and Paleontology. Have student partners work together to discover the tools and tasks "ologists" in these fields undertake.

  • If your technology supports it, show students the documentary on the Institute of Human Origins' Becoming Human website ( Macromedia Flash Player required), a project to which Alemseged contributed while studying at the Arizona State University. Invite students to listen to the documentary and explore some of the related exhibits and resources.
Related Links: