[ORDER SOLUTION] Anthropology Analysis of human ancestors Lab Report

Question: How can we interpret Homo floresiensis or Homo naledi within the broader context of what we know about human evolution? Background In lab, we are racing through a quick understanding of human evolution. Part of our goal is to determine trends in human evolution, things like a gradual increase in brain size over the past two million years, or a piecemeal transition to bipedality over the past 8 million years. At this point, we have a strong understanding of at least the broad patterns of human evolution, and have a sense where most of our fossil ancestors fit in to the bigger picture. But recently, a few mysterious fossil species have been discovered that have overturned some of our preconceptions about the general trends in anatomy that we have constructed over the years. On the small island of Flores in Indonesia, scientists discovered the skeletons of two human ancestors in the sediments of a cave. The skeletons are about 3 feet tall, with long feet, and small heads. The dates for these fossils are currently set at somewhere between 60-150 thousand years ago, with stone tools dating as far back as 800,000 years ago. The species have been assigned the name of Homo floresiensis. How we interpret this species, though, is still a mystery. Some people believe that it is a dwarfed modern human. Others, because of the dates and where it was found, think it might be a pygmy Homo erectus. Still others find similarities in the cranial and postcranial anatomy with Homo habilis or Australopithecus sp. This last pair of options would be exciting, as both of those species would have been extinct for more than 2 million years in Africa when Homo floresiensis was thought to be living in Indonesia. In South Africa, a newly-discovered species called Homo naledi was found to be living between 250,000 and 350,000 years ago. The remains of many different individuals of this species have been discovered scattered across the floors of several different cave systems in South Africa, suggesting to researchers that this species may have intentionally dragged their dead to these cemetary-chambers. The anatomy of this species is also surprising. Though not as small-brained as Homo floresiensis, Homo naledi did have a surprising combination of anatomy. Their skulls seem very similar in size to that of Homo habilis, while some of their post-cranial anatomy suggests connections to Australopithecus. In these two projects, you will select one or the other of these species, examine their anatomy, compare it to other appropriate species, and then make a determination as to which they most resemble, ultimately arguing which species they most likely evolved from. Methods For this report, you will need to have access to actual or digital copies of the skulls. Most skulls we have available to us in the Anthropology Lab. However, if working on this at home, you can find a great selection of skulls (including Homo floresiensis and comparative skulls) at the Bone Clones Rotation Series link: http://www.boneclones.net/portal.php. The skull of Homo naledi is available on the Morphosource webpage. • Examine the subject skulls carefully. You can assess them quantitatively or qualitatively for the key traits that are used to identify the species that you are comparing them to. For example, Homo sapiens can often be identified by having a small face, widest part of the skull near the top, canine fossa, and a chin in the mandible. Does your species have these traits? • Be sure to compare your species with several others, recording similarities and dissimilarities to each. • Review your results, and make a final determination. Which species do they most resemble? Report Write up the results of your investigation. Your report should include the following sections: • Background. In your project report, try to follow the outline of the scientific method. Start with a short description of the observation and question. • Hypothesis. Generate a testable hypothesis (following the guidelines for hypotheses that we discussed on the first day of class), and present that hypothesis at the start of your report. • Methods. Describe what data you gathered, how you gathered that data, what things you measured, what tools you used, and anything else you think might help your reader to understand how you got your data. • Results. Summarize the results of the data. In this section, a table or chart might be useful. This section should ideally present results without interpretation of those results. • Discussion. Use the next section to summarize what the results mean, and whether they support or reject your hypothesis. This is the section for interpretation. • Reflection. This section should be a short paragraph where you think about the validity of your results. Did you have enough data? Would your results still stand if you had more things to measure? Were your tools sufficient? What might you do differently if you repeated the project? Formatting Ideally your report should be typed, though neat handwriting is also acceptable. You are encouraged to include drawings, sketches, photographs, and so on to add clarity to your report. Single-spacing is ok, though double-spacing is preferred. Writing should be clear and direct, so that the reader may easily follow what you are saying, and so that the reader may easily replicate your methods if they choose. Your report should be free of spelling and major grammatical errors.