AW Anthro
Describe all examples of absolute methods of dating we discussed in class, including the date range that each method can measure.
Radiocarbon dating can date organisms younger than 50,000 years old. Radiopotassium dating can date organisms younger than 200,000 years old. Dendrochronology uses a tree ring concept to determine the exact age of organisms.
Describe all examples of relative methods of dating we discussed in class, including the limitations of each method.
Stratigraphic correlation -chemical dating -fluorine dating -biostratigraphic dating serves as an example of relative methods of dating. These methods can't pinpoint an exact date of when organism's occurred like many absolute dating methods can.
Explain the Out-of-Africa, Multiregional Continuity, and Assimilation models of modern human evolution and consider skeletal, behavioral, and DNA evidence for and against each model.
The Out-of-Africa, Multiregional Continuity, and Assimilation models of Human evolution are all different, and correct, in their own ways. Beginning with the Out-of-Africa model, it can easily be concluded that our species of Homo Sapiens first resided in Africa. There is hard fossil evidence that proves this claim relatively easily. The multiregional continuity model plays into the hands of the Out-of-Africa model, as species began to develop in Africa, gene flow took place on other parts of the globe, creating similar species in different parts of the world. This is seen with the early modern Homo Sapiens species in Europe and its similarity to neanderthals and Asian and African Homo Sapiens.
Compare relative age and relative dating methods with numerical age and absolute dating methods.
While there are many relative dating methods as well as absolute dating methods, there are clear differences with these two models that allow them to be used in specific circumstances. Relative dating methods provide a rough sample size of when something occurred in time. Absolute dating methods can put an exact date when something occurred in time, therefore making these dating methods more accurate and effective.
Explain the characteristics of basal anthropoids, and discuss whether Africa or Asia is the ancestral home of higher primates.
•Eosimias China; 42 million years old Teeth anthropoid-like, Short heel •Biretia Egypt; 37 million years old Asia as the home of basal anthropoids
Describe the characteristics of plesiadapiforms and euprimates and compare them in terms of skeletal anatomy.
-Plesiadapiforms also have a relatively small brain and quite specialized, sometimes rodent-like teeth -Euprimate have grasping hands and feet with nails instead of claws, they have larger brains and more generalized teeth than the plesiadapiforms, and they have forward-facing eyes surrounded with bone (a postorbital bar). -Some of these fossils are from animals as large as house cats, and others as small as chipmunks. They are found in fossil deposits in Western Europe, North America, Africa, and Asia, and generally fall into two categories
Explain the anatomical changes that were brought about by the transition to agriculture, including the masticatory-functional hypothesis (as well as other important anatomical changes!).
A general trend that we can trace from about 2.5 mya to the Holocene is a general reduction in robusticity of the chewing muscles and the teeth Masticatory-functional hypothesis. As humans began to eat soft-textured agricultural foods like millet, the chewing musculature has been reduced. The softness of grains was further increased by cooking them in pottery containers until they were soft mushes that do not need to be mechanically broken down by a strong masticatory system. By reducing the activity of the temporalis and masseter chewing muscles, the bones of the face and skull undergo less strain, grow less, and produce a skull that is more globular, with a less-projecting face. The less-projecting face results in less room for the teeth, leading to an increased rate of malocclusion. This mismatch is so severe that it can lead to molar impaction, infection, and even death, in the absence of dental care. Skeleton: One tool physical anthropologists use to reconstruct the life of Neolithic humans is called biomechanics. Because bones are somewhat plastic during development, their shape can be strongly influenced by the activity patterns of the growing individual. Larger, thicker bones, for instance, tend to reflect higher levels of activity. More specifically, biomechanists use the principle of an "I beam" to reconstruct ancient activity patterns. Material that is farther away from the center of the bone is stronger (resists bending) than material closer, in much the same way that a ruler can very easily be snapped in half by bending it in one direction (along the flat edge), but it much stronger and resistant to bending along the other axis (perpendicular to the flat edge). Skeleton: Researchers have discovered that the transition from hunter-gatherers to agriculturalists resulted in a significant decline in bone strength. Notice that these early prehistoric farmers from Georgia had considerably thinner bone than hunter-gatherers, reflecting reduced mechanical stress, and a lower overall activity pattern. In addition, it has been found that humans reduced their bone mass as a result of their smaller size. Of course, this depends on the local environment, but, in general, humans have had a 10% decrease in body weight in the last 20,000 years. As a result of agriculture, we did not get bigger, we got smaller. Skeleton: But, the reduced activity patterns also has led to a reduction, in some populations, of degenerative joint diseases, like osteoarthritis. Excess stress on joints from carrying, lifting, and any physically demanding activity, can breakdown the protective joint cartilage over time, and lead to excess bony growth. This happens most often in the spine, hand, knee, and hips. Shown here is the osteophytic lipping, or "spurs", that can form from arthritis of the lower back. These pathologies are often found in skeletons of individuals who were quite active. Of course, for some individuals, the shift to farming dramatically increased work load, and osteoarthritis is rampant in those individuals.
Explain how Homo habilis is similar to and different from the australopithecines.
Although we find stone-tool technology in the smaller-brained Australopithecus genus, it is a combination of stone-tool culture, larger brain size, and smaller tooth anatomy that can be used to identify fossils from our own genus. Of course, the evolution of our genus did not happen overnight, and so there are transitional fossils older than 2 million years old that bridge the anatomical gap between Australopithecus and Homo, and some researchers call these fossils Homo and some call them Australopithecus. The brain was larger than that of an Australopithecus (~600 cc), the teeth were smaller, and the landscape was littered with Oldowan stone tools. In fact, these tools were evidence of a dietary change that would have selected for smaller, rather than larger, teeth. This dietary shift may have been critical in providing the energy necessary to grow a large brain, as well. Additional finds of H. habilis have revealed that this species probably had an Australopithecus-like body, with relatively long arms and short legs.
Discuss the environmental and populational impacts of agriculture, including the Neolithic demographic transition.
As humans grew more and more food, these resources could support more and more people. But, these resources were not necessarily mobile, and humans began to settle into more permanent communities called villages. Soon after, these villages grew in size and developed into cities. Neolithic humans all over the world began to plant seeds and grow their own food. In China and Southwest Asia, for instance, people domesticated rice by 8,000 years ago. In Mexico, corn was domesticated around that same time. This idea spread throughout the Americas, quickly reaching the American Southwest, and eventually making it all the way to the Atlantic coast by about 1,000 years ago. There is little evidence that the corn itself was moved from Mexico to these other places. Instead, the knowledge of how to grow corn spread from community to community. The same thing happened in Europe, as the domestication of wheat and barley, which began in the Middle East, spread to Greece by 8,000 years ago and into western Europe. We have neglected to mention the domestication of animals in this whole process. In fact, the very first thing domesticated was probably not a plant, but an animal: dogs. There is evidence that humans domesticated the local wolf by about 15,000 years ago, and some evidence it dates back to over 20,000 years ago, leading to dogs that were helpful in hunting and guarding. Eventually, wild cattle, sheep, and pigs were domesticated for their meat, milk, and their coats. Domestication allowed humans to grow enough food to sustain a massive population growth at the beginning of the Holocene. This population boom continues today. Two-thirds of all calories and protein intake comes from cereal grains, like wheat, barley, corn, and rice that were domesticated in the early Holocene. Rice alone accounts for 50% of the caloric intake of nearly 2 billion humans. Agriculture has driven many technological innovations that allow us to grow, store, and transport more and more food to a growing population. Neolithic demographic transition: The greater availability of grains cooked into soft mushes allowed mothers to wean their offspring earlier, allowing them to have more offspring, and, ultimately, have a higher fertility over the course of their lives. Prior to the advent of agriculture, it is estimated that there were about 2 or 3 million humans. But, only 8,000 years later, there were 100 times as many humans: close to 300 million. And today, there are more than 200 times as many humans as 2,000 years ago: 7 billion. There are consequences for this many people crammed into a limited amount of habitable space. The use of land to grow food to sustain our growing population has led to soil erosion, overgrazing, and deforestation. There is one more negative byproduct of the Neolithic demographic transition that we should examine before moving on: violence. Growing populations led to more competition for resources, and more competition for resources resulted in more violence and organized warfare for access to land useful for growing food.
Discuss the changes in human health, including the costs, that occurred with the transition to agriculture.
As we've already seen, agriculture and population increase are intimately connected. Infections, such as those caused by the staphylococcal bacterium, Staphylococcus aureas, can impact bone growth, causing a swollen region called a periosteal reaction. Lesions on the skull are often accompanied by legs bones that are enlarged and bowed. A group of diseases called treponematoses, which can include syphilis and yaws. Other diseases found in the skeletal remains of Neolithic humans include tuberculosis, measles, mumps, cholera, the flu, and smallpox. There is skeletal evidence that many of these diseases were, in fact, present in overcrowded regions of the New World prior to European contact. One of the negative results of eating domesticated plants is the increase in dental caries, or "cavities." Many domesticated plants are rich in carbohydrates, which support the growth of bacteria like Streptococcus mutans and Lactobacillus acidophilus. These bacteria produce lactic acid, which literally dissolves the enamel of the tooth. For Neolithic humans, dental carries could lead to gum infections that could ultimately be fatal. Domestication of plants and the adoption of farming leads to a narrowing of the types of plants and animals consumed by a population. There is evidence that agriculturalists eat a very specific food in a given region: rice in Asia, wheat in Europe, millet or sorghum in Africa. Without the variety, agriculturalists are at risk for nutritional deficiencies. For instance, corn is lacking in three amino acids and a person eating almost exclusively cornmeal will have growth deficiencies as a result. Also, corn contains phytate, which can prevent the body from absorbing iron, causing iron deficiencies. If an individual is in nutritional distress, their body either slows or ceases growth. This is most obvious in the teeth, where ameloblasts (cells that make enamel) will halt production in times of nutritional stress. This creates lines on the teeth, like the ones shown on this juvenile skull, called enamel hypoplasias. The most common source of iron, however, is meat, and an iron deficiency may signal a lack of meat in the diet. Iron deficiencies can also be caused by infection, such as the hookworm (upper left image), which anchors to the intestinal wall and literally sucks the blood of the host individual, causing iron loss and anemia. When iron is deficient, the body responds by making more red blood cells. This leaves a mark on the skeleton, since the marrow-producing regions of the body (especially in the skull) become more porous to increase the surface area of blood cell production. This results in a porous texture to the top of the skull (porotic hyperostosis), shown in the top right image, and a projection of spongy bone into the eye orbits (cribra orbitalia)
Describe the climate and habitat changes that occurred in the Miocene and how these affected apes and primate diversity.
At the beginning of the Miocene, the planet once again warmed, creating new and expanding forest habitats for the catarrhines. By about 23 mya, the catarrhines diverged into two lineages: the hominoids (or apes) and the cercopithecoids (or Old World monkeys).
Compare and contrast the physical and behavioral characteristics that differentiate early hominins from apes.
Bipedal locomotion and non honing chewing set them apart. Foramagnum positioning Spine Knees Pelvis
Explain the anatomical characteristics that reflect bipedalism, bipedalism's costs and benefits compared to quadrupedalism, and the three major hypotheses for bipedalism's origins.
Darwin's hunting hypothesis is one hypothesis examined. Darwin theorized that hominins evolved in Africa. Darwin also established that hunting meat meant tools were used, and tool use represented large brain sizes, small canines and free hands. Darwin's timing was off in the development of these features, but the basis was there. Rodman and McHenry developed the "patchy forest" hypothesis, a second hypothesis. Hominins were said to develop and evolve during the late miocene, while Africa was experiencing significant cooling and drying in their forests. Finally, Lovejoy's provisioning hypothesis served as a basis in terms of interbirth intervals and infancy.
Compare the dryopithecids and the sivapithecids in terms of anatomy and geographical distribution.
Dryopithecids expand to Europe, specifically Spain, France, Germany and Greece. Dryopithecids have proconsolid-like teeth and bodies like modern apes. Sivapithecids expanded to Pakistan and India. They are hard food eaters, seen with the thick enamel on their teeth. They also have an orangutan-like skull and a proconsolid-like body.
Describe the skeletal characteristics of primates in the Miocene and compare and contrast them with modern apes.
Dryopithecids expand to Europe, specifically Spain, France, Germany and Greece. Dryopithecids have proconsolid-like teeth and bodies like modern apes. Sivapithecids expanded to Pakistan and India. They are hard food eaters, seen with the thick enamel on their teeth. They also have an orangutan-like skull and a proconsolid-like body.
Trace the geographical spread of Miocene apes and explain the importance of the apes moving back to Africa in the late Miocene.
During the late Miocene, the planet cooled and dried, and the great Eurasian forest receded back to equatorial Africa. Even in Africa, the vast forests became patchier, surrounded by woodlands and even grasslands.
Discuss the evidence for human migration to the Americas, Australia, and the Pacific Islands and the features of fossils found there.
Evidence for human migration to the Americas, Australia and the Pacific Islands was found through competition and the discovery of uninhabited regions at the time. Because of the setup of the terrain at the time, the migration to these regions represents further, more complex tool use, this time with the construction of boats.
Explain how fossils are formed and why they are not equally prevalent in all areas.
Fossils are the remains of once living organisms. Fossils transform into rock, most commonly sedimentary rock, through chemical processes and replacements. Fossils are not always prevalent in all areas because scavengers can get to the remains of organisms before they truly begin to Fossilize.
Discuss the migration patterns of Homo erectus.
H. erectus expanded both within and outside of Africa and quickly inhabited Europe and Asia. H. erectus is, therefore, the first global human species.
Describe methods for determining past temperatures
High oxygen-18= low temperature Low oxygen 18= high temperature
Discuss the three groups of primitive higher primates found in the Fayum: oligopithecids, parapithecids, and propliopithecids.
Oligopithecids are the oldest anthropoids (35 mya) consisting of the basal anthropoids, Eosimias and Biretia. Parapithecids have a 2/1/3/3 dental formula. Propliopithecids are between 29-32 mya in age and consist of aegyptopithecus.
Discuss the importance of domestication to the evolution of modern humans.
However, as with other major evolutionary events, the climate most certainly played a role. When looking at the global temperature over the course of the last 120,000 years. Notice that during most of the last 100,000 years, the climate was cooler, drier, and highly variable. In such conditions, it would be difficult for crops to grow consistently, given the rapid fluctuations in local environments. However, starting around 11,000 years ago, Earth emerged out of the last glacial cycle (ice age), and became warmer. But, perhaps more importantly, it became more stable. This stability meant that local climates were predictable and humans could more easily rely on what they grew from year to year for survival. Around this same time, there is evidence that humans began to selectively choose teosinte (to the bottom left) with larger and larger seeds—the beginning of maize domestication. The tool shown at the bottom right of this slide is an antler with blades inserted into it, which was used by Neolithic humans to harvest wild plants. But, domestication does not happen without people, and there is evidence from all over the world that population growth may have also triggered domestication. As populations grew, humans could no longer support themselves with hunting and gathering techniques. They needed more food, and deliberately growing it, storing it, and controlling its distribution not only allowed populations to grow but encouraged these populations to become more anchored to a piece of land. Village life, with permanent settlements, began to appear in the archaeological record around this time.
Describe the similarities and differences between early archaic and early modern Homo sapiens in Africa, Europe, and Asia.
Modern homo sapiens in Africa had a large face with a massive browridge, heavily worn teeth, and a large, modern human brain size. Similar traits were observed in Asia, representing potential gene flow. In Europe, however, homo sapiens had a projecting face with a wide nose, which is now known as facial prognathicism.
Describe salient facts and features of key Homo erectus fossil finds such as Nariokotome boy, Java, and Dmanisi
Nariokotome: Unlike Australopithecus and H. habilis, this skeleton has human-like limb proportions. In other words, the legs are quite long and the arms are quite short. This anatomical change indicates that H. erectus walked just like modern humans do, and that they were no longer climbing trees. This skeleton is from a young boy, perhaps only 11 years old or so at the time of his death. But, he was already 5 ft 6 in. tall, and probably would have grown more, perhaps reaching 6 ft. Thus, unlike previous hominins, H. erectus was quite tall. Additional fossil discoveries have revealed diversity in body size, however, so not all H. erectus individuals were this tall. He has a relatively large brain, about 900 cc. At this size, his brain was larger than the typical H. habilis (~600 cc), but smaller than a modern human (~1,400 cc). In fact, the cranial capacity of the Nariokotome boy is exactly between the average chimpanzee and the average human.
Describe the unique anatomical and behavioral features of the Neanderthals and describe the "Neanderthal world" in terms of landscape, climate, and dietary practices.
Neanderthals have greater facial prognathicism than European homo sapiens did. Also, neanderthals are stalker in body shape than modern homo sapiens. Finally, neanderthals continue the trajectory of human-like brain size. The Bergmann and Allen rules come back into play with neanderthals, as they are both cold adapted and heat adapted based on their limb proportions and bodies. Also, cutmarks on some neanderthals potentially show cannibalism between species.
Provide specific examples contradicting early paleoanthropologists' assumptions that Neandertals were brutish and stupid.
Neanderthals made a sophisticated tool-type called the Mousterian. The Mousterian was characterized by a specific kind of flaking technique called the Levallois. Essentially, a stone core was carefully and deliberately prepared by removing small flakes from the perimeter of the rock so that one blow could produce an effective scraping or cutting tool. Levallois stone-tool construction is not easy and requires careful planning and hand-eye coordination. Neanderthals were also successful hunters. There are abundant bones of butchered animals at Neanderthal occupation sites. Furthermore, isotopic analysis of Neanderthal bones reveal that they had a bone and tooth chemistry similar to that found in carnivores. Meat was a huge component of their diet, and that Neanderthals must have been quite good at hunting. But, Neanderthals did not just eat meat. Recent studies have looked at the calculus, or what you and I would call plaque, that still remains on Neanderthal teeth. Scientists have scraped this material off fossil teeth and have found evidence that Neanderthals ate plants, some of which were cooked. Additionally, there is some evidence that Neanderthals ate plants that did not have any nutritional value, but may have been used for medical purposes. Evidence is mounting that Neanderthals were quite intelligent, that they spoke, and that they had symbolic representations of thought. First, one of the reasons that we have so many Neanderthal fossils is that they deliberately buried their dead. La Chapelle, Amud, and Shanidar were all found in burial pits, flexed in a fetal position, indicating that they were carefully and purposefully positioned in their graves. Human language is so integral to who we are as a species and it was undoubtedly critical to our survival, given how ideas and information can be easily exchanged through speech. A hyoid bone was found in the Kebara skeleton and it is exactly the same shape as what modern humans have. Furthermore, there is evidence that Neanderthals had brain laterality (right and left sides), which is linked to speech. The scratches on the back of incisors (shown on the right) are not random, but are oriented in a way that could only have been made by a right-handed individual cutting meat that was being gripped by the front teeth. This means that the Neanderthals had brain laterality like that found in modern humans, and, therefore, may have talked. Neanderthal genetics is also indicating that this population talked. A gene called FOXP2 has been linked to speech production in modern humans, and Neanderthals had the exact same version of the gene as humans have today. Finally, more and more evidence is showing that Neanderthals used symbols. They decorated themselves with perforated-shell necklaces and with skin-staining pigments, like red ochre.
Describe the australopithecines we discussed in class, including the differences in anatomy and chronology between the robust and gracile australopithecines.
The australopithecines also experienced a slight increase in brain size. They had gorilla-sized brains in chimpanzee-sized bodies. Australopithecus became well-adapted for eating difficult-to-process food, and evolved large jaws with enormous premolars and molars. This increase in tooth size reversed around the time that hominids began making stone tools and eating more meat
Describe the anatomical characteristics that differentiate and define modern and archaic Homo sapiens.
There are many characteristics that differentiate and define modern and archaic humans. One of these characteristics that goes without saying is a large brain. With a larger brain comes smaller molars and premolars, but larger incisor teeth that are worn down. Large faces with massive browridges were also seen in hominins as well.
Explain the chronological and geographical variation in plant and animal domestication in the world.
Up until about 10,000 years ago, all humans around the world were hunters and gatherers. They collected a wide variety of plants, hunted game (both large and small), fished, and collected shellfish. But, at the transition of the Pleistocene to the Holocene (a transition period called the Neolithic), humans began to domesticate some of the local plants and animals. This, of course, did not happen overnight, and shown here is an illustration of the gradual shift from a hunter-gatherer lifestyle to one that relies on agriculture. Eventually, many of these domesticated plants and animals grew to rely on human intervention to survive and reproduce, resulting in a completely dependent and mutualistic relationship among humans and our domesticated crops and our animals. Archaeological evidence also shows that domestication did not start in one place and spread. Instead, it took hold independently in at least 11 regions around the world. Certainly from these central areas, the idea spread quickly through a process called diffusion. The only region that did not adopt agriculture was Australia. The 11 epicenters of plant domestication are shown in this map. Notice that in each region, different plants (locally found) were domesticated, like maize in Central America, sunflowers in North America, wheat in the Middle East, and bananas in New Guinea. Notice, too, that domestication did not happen all at once, but instead took time to diffuse, with southwest Asia being the first region to yield evidence for domestication and the eastern United States and sub-Saharan Africa being some of the last regions. Domestication appears to have begun first in a region called the Fertile Crescent in the Middle East, followed soon after by evidence for plant and animal domestication in Central and South America, and in China. Again, this did not happen overnight. The archaeological and genetic evidence finds that Neolithic humans in the Middle East, for instance, were harvesting wheat and barley for part of the year, and then hunting and gathering for the rest of it. At some point, these people noticed that the seeds that fell off the wheat and barley made new wheat and barley plants. Their selection of particular seeds to deliberately plant started a long (and continuing) practice of controlling the life cycle of plants.
