The theory of natural selection provides a scientific explanation for the history of life on earth as depicted in the fossil record and in the similarities evident within the diversity of existing organisms. In this activity you will explore how physical features noted in the fossil record provide clues about the evolution of species.
To begin your study of the fossil record, read the text found at the top of the Human Evolution: You Try It page. Then access the Human Evolution activity by clicking on that link at the bottom of the text and read the instructions provided. Use your mouse to slide the hand across the timeline that appears. You also should roll the cursor over the images in order to learn more about the various species, paying attention to particular physical features that changed over time. When you are done, click on the "show tree" button to see how the hominids might have been related. As you are exploring this resource, think about answers to these questions and record your answers on the Human Origins student sheet. You will discuss them with your class.
- Look at A. ramidus, the most primitive of hominids found. Compare and contrast humans today to A. ramidus.
- Follow the "tree" over to Lucy and then to Homo habilis "handy man." What physical changes do you note between the two?
- How do you think the use of tools by "handy man" possibly changed the lives of Homo habilis?
- Do you think those tools led to what we have today?
- Now follow the "tree" up to Homo erectus and then over to Homo sapiens. What changes in traits do you notice?
- Finally, look at Homo sapiens. Generally, how do we differ from the various species that came before us? (Think about external physical traits, bone structure, language, and culture.)
- What similarities do you think there are between humans and the species that came before?
- Do you think there are more differences or similarities?
- Can you think of other species today that have evolved from earlier species, but are quite different from those earlier species?
To learn more background information and explore more distinct physical differences between early hominids and today's species, visit Outpost: In Search of Human Origins, from National Geographic. Click on "Outpost" to access the website. Now click on "Interpretation Station." Here you will find a list of four articles. You will need to read the first, What's a Hominid? and the third, Hominid Family Photo Album. Both articles address the the topic of physical features. Think about answers to these questions as you are reading the articles:
- What physical feature first separated hominids from apes?
- What are some advantages of bipedalism?
- What did the curved fingers of the very first hominids most likely represent?
- How did the upper limbs of hominids change over time? What do these changes indicate?
- How did hominid tooth enamel change over time? What does that change imply in regard to behavior?
- How did hominid canine tooth size change over time? What may this represent?
- Describe the usefulness of looking at fossil records.
- Describe some limitations of using fossils to piece together our past.
Imagine that you are out in the field assisting on a fossil dig. Create a journal that describes a discovery you made of an early hominid fossil. You can use the Comparing Species through the Fossil Record student sheet to help you do this activity. Use these sites to "find" your fossil and gather information about it.
This esheet is a part of the Comparing Species through the Fossil Record lesson.