Where Do We Come From? An Introduction to Primate Biology GK-12 Inquiry Science Lesson Kristin De Lucia Fall 2002 Background: This lesson is designed to correspond with units on human anatomy, especially skeletal biology. Students should already be familiar with basic human skeletal anatomy and should know some functional aspects of anatomy (i.e. diet may be reflected by type of teeth, etc.). Primates are all members of the mammalian order Primates including prosimians, monkeys, apes and humans. Teachers may want to review different types of habitats and emphasize that primates are mainly adapted to tropical environments and are best adapted for arboreal living. Even though some primates spend the majority of their time on the ground, all primates spend some time in the trees, and most primates spend almost all of their time in the tress. Grade Level: Grade 7-8 Objective: Students will learn why humans are classified as primates and what specific features we share with the other members of our Order. Students should also gain a better understanding of why human anatomy is the way it is, and realize that most of our abilities are a result of an ancestral arboreal lifestyle. This activity will foster an understanding of how organisms, including humans, are adapted to their environment and that anatomy is a reflection of these adaptations. Moreover, students will gain an introduction to methods (and difficulties!) of classification used by evolutionary biologists. The teacher should emphasize that non-human primates are not our ancestors, but are rather close relatives with whom we share common ancestors. Standards (for Arizona): Standard 1: Science as Inquiry 1SC-E1: Defend conclusions drawn from analysis Standard 2: History and Nature of Science 2SC-E3: Analyze different theories to explain a phenomenon Defend or refute the explanation of a phenomenon 2SC-E4: Describe Scientific processes: observing, relating, inferring, and applying 2SC-E6: Demonstrate that science is an ongoing process of gathering and evaluating information, assessing evidence for ad against theories. Standard 4: Life Science 4SC-E5: Describe organism adaptations or constancy over geologic time.
Identify environmental factors that may determine adaptations or constancy of an organism over geologic time. Materials: q One monkey, one canine, on human skull for Station 1. (If more skulls are available, may also want to include a rodent skull for additional comparison). q One monkey, one canine, one ape and one human skeleton (or diagrams of skeletons) for Station 2 q Video clips demonstrating various forms of primate and non-primate locomotion Time: Two 50-minute class periods Background information: Why study primates? Begin with discussion of why scientists would want to study primates. Be sure the following points are covered: We are primates Modern non-human primates are our closest relatives, but not our ancestors The study of primates provides us with information of what our ancestors (hominids) may have been like (behavior, diet, social patterns, etc.) We can learn about ourselves by studying primates (why we are the way we are) Procedure: This lesson should be done by breaking students into groups and setting up lab stations. Depending on the size of the class, more materials may be necessary for the set up of multiple lab stations. The ultimate objective is for students to understand the evolutionary history of human skeletal anatomy. Station 1. Cranial anatomy So, what are primates anyway? The objective of this activity is to emphasize some of the distinguishing characteristics of primates. 1. Using the attached worksheet, students will compare a dog cranium (or any other type of mammal) to a non-human primate skull. Students are asked to make a list of all features that differ between the dog and the primate skull and then discuss what physical or behavioral significances they may imply. Finally they are asked to determine which features are found in the human. 2. Students are then asked to respond to questions at the bottom of the worksheet. They should discuss as a group the answers to the questions and then report back to the class as a whole. The following points should be addressed during class discussion:
Humans are much more similar to non human primates than other mammals. Physical similarities correspond to many behavioral similarities Features to discuss: Primates have a shortened face and larger braincase, reflecting a reduced reliance on smell, as well as an increase in brain capacity. This should be related back to emphasis on vision and the complexities of arboreal life. Humans retain these features and have an even larger brain capacity, which has enabled them to expand into all corners of the globe. Eyes are larger and face forward providing stereoscopic vision necessary for both locomotion in the trees and hunting (note that predators have more forward facing eyes). This preadaptation to stereoscopic vision is very important for human survival (ex: enabled humans to become expert hunters). Postorbital bar (and plate in most primates) ensures that vision is not impaired during mastication as well as protecting eyes from damage. Again, empasis on the importance of vision. Teeth are reflective of an omnivorous diet diverse diet of fruit, leaves, insects, meat and nuts for many primates. Humans also are omnivores and this diverse diet has enabled them to exploit many different niches which may have been otherwise unavailable. DAY 2 1. Show video of monkey and ape locomotion. Distinguish between quadrupedal locomotion and suspensory locomotion in primates. The teacher should demonstrate different types of joints (ball and socket, hinge, gliding joint etc) and ask students to determine the types of motions that could be accomplished by each joint type. Station 2: Postcranial anatomy 2. Using the worksheet for Station 2 students should compare the dog, monkey and ape skeletons. Students should be asked to list features that differ and what behavioral significances they may imply keeping the video in mind. They should then compare to the human skeleton and see which animal the human most closely resembles for each feature. 3. They should then answer the questions as a group and report back to the class as a whole. The following points should be addressed: 1. Primates are adapted to some degree to an arboreal lifestyle. Many anatomical features are an adaptation to this lifestyle. All primates, including humans: Have full extension as well as rotation of limbs for arboreal locomotion They have grasping hands and feet with an opposable thumb, allows greater mobility
Primates have nails rather than claws to support grasping fingers. Contrast with dogs, which do not have full extension, rotational movement and have claws Primates have a more general locomotor anatomy which is not restricting to one form of movement Apes are adapted to suspensory locomotion. Therefore, they have longer arms than legs have curved fingers have shoulder blades positioned posteriorly allowing a greater range of motion lack a tail Students should be asked to hypothesize about how these anatomical differences relate to the different styles of locomotion seen in the video. Why would an arboreal lifestyle necessitate the cranial and post-cranial adaptations discussed above? These traits should be compared and contrasted with humans. Ultimately, students should understand that the human success on the ground is a result of the primate success in the trees. We would not be able to draw, type, play basketball, make tools if not for the preadaptation of grasping hands. Stress the importance of our eyes, brain, hands, diet, and locomotion in our success and how they relate back to an arboreal lifestyle. Discussion of the hominid adaptation to bipedalism can be touched upon or discussed in further depth in a following class session. Evaluation: Students should be able to make accurate observations and be able to compare and contrast the different skeletons given to them. They should be able to relate this information to what they have previously learned in class and thus infer the functional significance of the anatomical differences that they observe. They should then be able to apply this information to new situations provided by the teacher such as the application to humans or an entirely different situation created by the teacher for assessment purposes. Resources: The following resources may provide valuable background information: http://www.mnh.si.edu/anthro/humanorigins/ha/primate.html http://www.wwnorton.com/college/anthro/bioanth/ http://www.anth.ucsb.edu/projects/human/ Klein RG. 1999. The Human Career: Human Biological and Cultural Origins. Chicago: University of Chicago Press. 810 pp. Strier KB. 2000. Primate Behavioral Ecology. Boston: Allyn & Bacon. 392 pp.
Extensions: Numerous types of lessons that could extend from and draw upon this lesson including studies of habitat adaptation and ecosystems, animal behavior and social systems, the human adaptation to bipedalism, as well as nutrition and diet.