The Amazing “Human” Race

Background

     Human evolution is the lengthy process of change by which people originated from apelike ancestors. Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years. 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.

Humans are primates. Physical and genetic similarities show that the modern human species, Homo sapiens, has a very close relationship to another group of primate species, the apes. Humans and the great apes (large apes) of Africa -- chimpanzees (including bonobos, or so-called “pygmy chimpanzees”) and gorillas -- share a common ancestor that lived between 8 and 6 million years ago. Humans first evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between 6 and 2 million years ago come entirely from Africa.

     Most scientists currently recognize some 15 to 20 different species of early humans. Scientists do not all agree, however, about how these species are related or which ones simply died out. Many early human species -- certainly the majority of them – left no living descendants. Scientists also debate how to identify and classify particular species of early humans, and what factors influenced the evolution and extinction of each species.

     Early humans first migrated out of Africa into Asia probably between 2 million and 1.8 million years ago. They entered Europe somewhat later, between 1.5 million and 1 million years ago. Species of modern humans populated many parts of the world much later. For instance, people first came to Australia probably within the past 60,000 years and to the Americas within the past 30,000 years or so. The beginnings of agriculture and the rise of the first civilizations occurred within the past 12,000 years.  Because of advancements in genetics, only .1% of our DNA makes us different from other humans and that only about 2% of our DNA makes are species different from other primates like chimpanzees.  Human never descended from chimpanzees or other such primates; but instead we all shared a common ancestor some 7-8 million years ago.  Our common lineage continues to be made clearer with the help of other biological disciplines besides genetics such as: anatomy and physiology, embryology, and paleontology.

Procedure

Materials:

Common Ancestor Skull Replicates: Sahelanthropustchadensis (~ 6-7 myo) Australopithecus afarensis (~3.0-3 myo) Australopithecus africanus (~2.5 myo) Homo habilis (~2.4-1.4 myo) Homo heidelbergensis (~700-200 tyo) Homo neanderthalensis(~200 tyo-29 tyo) Homo sapiens (~200 tyo-present day) Skull Cards

Computer / Internet Resource Headphones Metric Ruler Magnifying Glass Caliper Cut Out – on card stock paper Large Paper Clip (“slide on” hinge) Scissors Resources

Steps: 

Part I: Research “Do Prior to Activity Outside of Class”

1. Develop a basic understanding of human evolution by exploring the following interactive documentary, which will help to explain our origins and our evolutionary journey.

http://www.becominghuman.org/node/interactive-documentary

Play, listen and understand the documentaries for the following titles:

Prologue, Evidence, Anatomy, Lineage, and Culture

2. After watching the documentaries, feel free to explore other areas of the website or other evolutionary facts.  Note other resource may be and have been provided for you.

Part II: Skull Stations “Done Just Prior to Activity”

1. Create your metric caliper by cutting the diagram out and using a paper clip.  Keep and use the caliper with you through the game; a metric ruler and magnifying, which stay with the skulls, is used to measure certain features of the skulls.

2. Cast of hominid skulls have been laid out for you to observe ancestrally human evolution representing a span of millions of years. 

TREAT THE MODELS WITH RESPECT AND CARE

Part III: Participating

     You are about to embark on an amazing race, the human race.  The hominid skulls you will be working with are real molds from real bones found to be thousands and even millions of years old from around the world.  The real trip will be to learn about these ancient human-like and human fossils but also to make you work for the opportunity to learn about your own evolution.

1. You and your partner will “race” around the school to locate a special “flag” (a multicolored paint swatch) that will indicate a staff member (office worker, teacher, administrator, etc…) who will ask you to perform a task.  In some cases, it may be a Roadblock (in which one of you decides to do the task – cannot switch out) or a Detour (in which both of you have to do the task); it’s up to the staff member.

2. If you complete the task to the staff’s satisfaction, they will give you a signed “skull card”; however, if the “skull card” is not signed, meaning you did not do the task to the staff member’s stratification within the allotted time, you will receive a time out penalty of 2 minutes once you get back to “our” room. Despite how you are doing or what the staff member is saying or asking of you, you must stop after 5 minutes and collect the “skull card” and get back to the room.

      Note: You cannot do tasks back-to-back; once you finish a task, you “must” return to the room with the                        

                “skull card”.  If you see another “flag” before or after a task, that’s fine, but again, you have to return  

                to the room and complete a station before doing the next task. 

3. Once in the room, show the “skull card” to the instructor.  The instructor will return the “skull card” to you. The “skull card” will provide a clue to which station you have to complete.   

At each station, use the skull mold, created caliper, metric ruler, and resources to answer the questions provided for each skull on your Answer Sheet.  Some answers will be objective and collaboratively agreed upon; however, some of your answers may be more subjective and confrontationally argumentative.  

Note: If you and your partner(s) challenge each other’s responses then that is acceptable and justifiable since  

          science is all about finding plausible answers based on facts and testable hypotheses. Questioning

          prevents ideas and concepts from becoming stagnate and may promote more plausible solutions to

          problems.

4. Once you complete a station, you’re off to find another “flag” (pending a non-signed 2 minute waiting penalty). 

5. In order to win the game and earn 150 points:

* Complete all tasks

* Complete all stations

* Complete all questions

* Complete the required drawing

* Perform a final task implemented by the instructor that will summarize the entire experience.

6. Do not run, walk fast… do not be loud and obnoxious in the hallways; follow school rules.  Areas (countries) to visit may include gym, agriculture building, office, and high school building.  If you decide to help each other, that’s up to you.

The World of Hominids is Waiting for You, Good Luck and Be Safe !

Questions: Place all answers on “Answer Sheet” Only; Note (If skull does not provide the answer, use N/A)

1. What is the age of the hominid skull?

2. Do you feel that the angle of the forehead (frontal bone) is great, minimal, or something in the middle when looking at the skull in profile?

3. Is a supraorbital brow ridge (the ridge of bone above each eye) present?

4. Based on the skull, how would you describe the eye socket shape and size?

5. Is a sagittal crest present anywhere along the top of the skull?

6. What is the shape of the braincase (the part of the skull that encloses the brain; the cranium) from front to back when viewed from above?

7. Using the pre-made calipers and metric ruler (in centimeters), what is the Maximum cranial breadth diameter (eu-eu)

8. Using the pre-made calipers and metric ruler (in centimeters), what is the Bizygomatic diameter (zy-zy)

Note:

EURYON (eu): Instrumentally determined ectocranial

points on opposite sides of the skull that form the

termini of the line of greatest cranial breadth. (Paired)

ZYGION (zy): Instrumentally determined as the

most lateral point on the zygomatic arch. (Paired)

9. Based on the teeth and jaw, would you consider this specimen a herbivore, carnivore, or an omnivore? 

10. If present, is the foramen magnum (hole at the base of the skull) oriented more downward or more to the rear?

11. Are the nasal bones anterior of the nasal opening raised or flat?

12. Do the back tooth rows diverge towards the front at an angle or are the tooth rows more parallel to one another with very little angularity?

13. When viewed from the side, are the incisors angled out, angled in, or vertical (straight up-and-down)?

14. From a scale of 1-7 (1 being the least likely), does the skull resemble a present day human model?

15. Based solely on the model (or any information provided), do you think the skull if female or male?

16. Where was this skull found according to information attached to the mold?

17. State at least one other characteristic (ie speculate on the intelligence level of the specimen) that makes the specimen a predator or even prey, or what features make the specimen different or similar to other mammalian primates such as chimpanzees, gorillas, or orangutans, etc….