Who knows the answers to this?

Activity 2: Dating

A. Many sites are dated first by biostratigraphy, or "faunal dating." The animal species found at a site are compared to those at sites of known age in order to estimate the age of the new site. At sites relevant to human evolution, pig fossils are very useful for this purpose. The attached biostratigraphy handout (last page) gives you a phylogeny of pigs and their time ranges for the last 6 million years. These dates are based on absolute dating techniques.

Using this information, place the following African sites in the correct order through time (showing which is oldest to youngest). Each site has at least two pig species present. The time of overlap for the pig species at each site will give you a time range for that site.

1. 1st, record the total time range for each pig species listed (the first one is done for you):

(remember, the older date is listed first)

Hadar South, Ethiopia Tulu Bor, Kenya

Kolpochoerus afarensis _3.6 – 2.9 mya Kolpochoerus limnetes

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Notochoerus euilus

Nyanzachoerus kanamensis

Notochoerus eulius Notochoerus scotti

Makapansgat, South Africa Hadar North, Ethiopia

Stylochoerus compactus Metridiochoerus andrewsi

Metridiochoerus nyanzae Phacochoerus modestus

2. 2nd, determine the time of overlap of the pig species at each site. This means the date range when those species were at the site at the same time.

Hadar South, Ethiopia Tulu Bor, Kenya

Time Range of Overlap

Time Range of Overlap

Makapansgat, South Africa Hadar North, Ethiopia

Time Range of Overlap:

Time Range of Overlap:

3. 3rd, list the sites (oldest to youngest) based on the time range of overlap.

1.

2.

3.

4.

4. One of the methods of absolute dating is Potassium-Argon dating. This method is used to date rocks that have been heated to a very high temperature, such as those that result from a volcanic eruption.

In this composite stratigraphy, the solid black lines represent ash fall layers, or tuffs, that have been dated using the K-Ar method. In between each tuff are geologic members, in which many fossils have been found.

1. What date would you assign to a hominid skull that was found in the KBS Member?

2. Which is older, the Upper Burgi Member or the Chari Member?

Part IV: Bipedalism: SLIDES #4-8 (39 points)

This section is designed to introduce you to the human body as it compares to our closest living relative, the chimpanzee, and one of our earliest fossil relatives, Australopithecus afarensis. The section focuses on aspects of the skeleton that relate to bipedal locomotion, and how to apply what we learn from extant species to those in the fossil record.

Station 1. Skull

1. Compare the position of the foramen magnum on the human skull to that of the chimp and the Australopithecus skull. Describe the differences in their position. For example, is the foramen magnum placed directly beneath the skull? Or is it oriented more toward the posterior surface of the skull?

Human: Chimp:

A. afarensis:

2. What does the position of the foramen magnum tell us about the body posture and locomotion in the two living taxa?

3. What is your opinion of Australopithecus based on the foramen magnum: is it like a chimpanzee, like a human or is it unique?

Station 2: Pelvis

Examine the pelvis of the human and the chimp.

1. Describe the ilium in each species as either tall and narrow or short and wide.

Human: Chimp:

2. Describe the ilium in each species as either flat or curved.

Human: Chimp:

Now look at the Australopithecus afarensis pelvis.

3. Is the ilium in A. afarensis tall and narrow or is it short and wide?

4. In your opinion, is it most similar to the human or the chimp?

Station 3. Limb Proportions

The intermembral index gives information about the proportions of the forelimb relative to the hindlimb. This can be used to determine locomotor behavior. Remember, the intermembral index is calculated as:

Intermembral index = {(humerus + radius) / (femur + tibia)} x 100

1. What does an Intermembral Index over 100 indicate about body proportions?

2. What does an Intermembral Index under 100 indicate about body proportions? Here are some intermembral index values for a number of hominoid taxa:

3. Which taxa have an IM Index over 100?

What does this suggest about their locomotor behavior?

4. Australopithecus is intermediate between modern humans and the apes. What does this tell you about their body proportions?

Based on this, what can we say about their locomotor behavior?

Station 4. Hindlimb

A. Knee Joint:

The shaft of the femur in humans and apes is either in line with the tibia, or at an angle to it at the knee joint. Whether or not the femur is angled can be seen when you stand the femur on its distal end on the table.

1. Determine whether the femur is angled at the knee joint or straight in these taxa: Chimpanzee:

Human:

A. afarensis:

If the femur is angled at the knee joint, we call it a valgus knee.

2. Based on what you can see in the femur, did A. afarensis have a valgus knee?

B. Foot:

Examine the foot of the chimp and the human.

1. What is the position of the hallux (big toe) relative to the rest of the foot in the chimpanzee and human specimens? Is it parallel to the other toes, or divergent?

Human:

Chimp:

2. Keeping in mind the differences in position of the hallux, describe how it is used for locomotion:

in humans:

in chimps:

3. Look at the toes bones (phalanges) in the human and in the chimp: are they short or long?

Curved or straight? Human:

Chimp:

4. Compare an Australopithecus toe bone (phalanx), labeled A in the picture, to those of the human

(H) and the chimp (C).

a. Is it straight like in a human, or curved like in the ape?

b. What advantages could this morphology offer to A. afarensis?

Compare the footprints of a human (Homo), a chimp (Pan) and one of the Laetoli hominid footprints.

1. Do the Laetoli footprints look more like a human or a chimp? Describe two features you use to answer the question.

Summary

Consider all of your observations about the skull, the pelvis, the limb proportions, the knees, the feet and the footprints of humans, apes and Australopithecines.

1. Is Australopithecus more like a human, an ape, or intermediate between the two in all of these features?

2. What do you think this tells us about the way Australopithecus moved? Do you think these animals were bipedal in the same way humans are? Why or why not?

Part V: Early homo SLIDES #9-10 (13 points)

Station 5: Homo habilis as descendant: comparing early Homo to early hominids

In 1960, Louis Leakey found a mandible at Olduvai Gorge. That, combined with subsequent discoveries, made him believe that it belonged to the first species in the genus Homo, H. habilis.

1. Looking at the brain, face and teeth, list three things that would have led him to this conclusion.

1.

2.

3.

These hominids, who appear roughly 2 million years ago possessed many derived cranial features that link them with the lineage that eventually led to Homo sapiens. Using your notes, fill in the cranial capacity for each taxa, then answer the following questions:

1. The dramatic increase in brain size is one of the unique features in humans. Do you see a dramatic change in brain size already present in early Homo?

2. What could this be attributed to (hint: think diet)?

Station 6: The first archaeological artifacts – Stone Tools

With the appearance of our genus, homo, comes the appearance of our first artifact, stone tools. These first tools were made by striking a flake from a stone core. These flakes and cores have certain characteristics that are a result of human work instead of natural processes.

1. These are SEM (scanning electron microscope) pictures of tooth marks and tool marks made on fresh bone. You can recognize a tool mark because it has fine striations within it and is V -shaped in cross-section. You can recognize a tooth mark because the bottom of the groove is smooth and rounded.

Which is the picture of a tool mark: A or B?

2. The Oldowan tool assemblage was not very sophisticated or varied. It consisted mostly of flakes and choppers. Looking at the pictures (c-e), label the following:

Flake:

Chopper:

Pounding Stone:

Part VI: Late homo SLIDE #11-15 (58 points)

Station 7. Comparing African H. ergaster to Asian H. erectus

Some anthropologists think that H. erectus is one species that had a wide geographic distribution over a long period of time. Other anthropologists consider the collection of fossils traditionally assigned to H. erectus to actually represent two species, H. erectus in Asia and H. ergaster in Africa and Eurasia.

Instructions: Examine the photos of H. erectus/H. ergaster. Fill out the chart below based on the features that you observe in these specimens using the words in parentheses as a guide. Use this chart to answer the questions that follow about the variation among these fossils.

* Remains of H. erectus/H. ergaster are dated from 1.8 million to 250, 000 years ago and possibly even younger.

1. Based on the features listed in your chart, describe at least two cranial features that appear variable within these specimens.

Station 8. Intermembral (IM) Index of H. erectus

Calculate the intermembral index for the three hominids.

Intermembral index = (humerus + ulna) / (femur + tibia) x 100

1. How does the IM index of H. erectus compare to those of Australopithecus and H. sapiens?

Compared to Australopithecus:

Compared to H. sapiens:

2. What might this change in limb lengths indicate about the locomotion of H. erectus in terms of how often they moved bipedally, the efficiency of their bipedalism, and the distance they could travel?

Station 9: Brain Size

Although bigger brains are known to be related to higher intelligence in a general sense, within a species, individuals with a larger head size aren’t smarter than their smaller-headed companions! When comparing brain size among various species, it is important to look at relative brain size: brain size compared to body size.

You can get a sense of this by determining relative brain size throughout human evolutionary history. The chart below provides you with data on average cranial capacity (cc) and average body weight for a number of species.

1. Calculate the ratio by dividing cranial capacity by body weight. The smaller the number, the smaller the relative brain size.

2. From your data, at what point in human evolution (so only consider the hominid species!) did the most significant increase in relative brain size occur? What is a possible reason for this (think behavior & diet)?

Station 10. Neanderthal cranial anatomy

1. Examine the picture of the Neanderthal skull. It has three letters on it, labeling traits that are found in Neanderthals. Give the trait for each letter on the skull. These are derived traits that define Neanderthals.

a.

b.

c.

Station 11: Neanderthal postcranial anatomy

Note: Use the YouTube Video Link in addition to the Powerpoint

Neanderthals are known to have had more robust limb bones and joints than modern humans. Compare the pictures of the femora to each other.

1. Which of these limb bones (white or brown) likely belonged to a modern human and which belonged to a Neanderthal? Support your answer with two reasons (color is not an indicator).

2. What does having more pronounced muscle markings suggest to you about the lifestyle (activities)

of Neanderthals?

1. Looking at the image of a Neanderthal skeleton next to a modern human explain the differences between the two in the three labeled areas.

a.

b.

c.

2. When we apply Bergmann’s and Allen’s rules to Neanderthals, what two traits in Neanderthal

anatomy are interpreted as adaptations to living in a cold environment?

a.

b.

Station 12: Comparing Heidelbergensis, Neanderthalensis, & Sapiens

Using your notes and the pictures on Slide X of H. heidelbergensis, H. neanderthalensis, and H. sapiens fill out the chart. Note: Use the YouTube Video Link in addition to the Powerpoint.

1. Compared to specimens of early Homo (H. habilis) that had a cranial capacity ranging between

~500-775 cc, is there a dramatic increase in cranial capacity in later Homo (H. heidelbergensis,

H. neanderthalensis, H. sapiens)?

2. Based on your chart above, list two unique derived Neanderthal traits. a. b.

3. Do you think these traits might exclude Neanderthals as an ancestor of H. sapiens? Why?

Part VII: The Archaeological record SLIDE #16-17 (58 points)

Station 13: Stone Tool Industries

1. Examine the pictures of tools. Remembering what you learned in lecture about each industry, try to determine which group belongs to the Oldowan, Acheulean and the Aurignacian. List the letter and your explanation.

Oldowan:

Why?

Acheulean:

Aurignacian:

Station 14: Upper Paleolithic Artifacts

Based on your notes, identify the artifacts in the slide and explain their use and/or possible ideological value. Note: Artifact B in the slide is a display of two of the same things.

What is it? What is its purpose?

Artifact A:

Artifact B:

Artifact C:

Station 15: The Archaeological Record

Using your notes, fill in the chart that summarizes important points about the hominid archaeological record.

Station 16: Geographical Distribution of the genus homo

Place the following sites in the appropriate boxes on the map. Also indicate what species is found there (you may write the name of the species next to the site).

Cro-Magnon Dmanisi Herto

Lake Mungo Neander Valley Olduvai Gorge

Shanidar Cave

Sima de los Huesos

Skhul & Quafzeh Cave

Trinil

Zhoukoudian Cave

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