Physical Anthropology Test 3

Types of absolute dating

-radiocarbon dating/carbon 14/organic material/75000-50000 years before now -dendrochronology/determind by tree growth uses its ring to measure/specific tree types/12000-8000 years before now -paleomagnetic dating/shifts in earth's magnetic field/sedimentary rocks/up to 5 million years ago

Types of relative dating

-law of superposition/older is lower/just about anything and any time period -stratigraphic correlation/like strate from different regions are related to the same event or time period/rocks and fossils and any time period -biostratigraphic dating/evolution of animals/bones and teeth and any time period -chemical dating/fossils absorb chemicals/bones/100,000 years before now -cultural dating/artifacts are time-specific/technology generally/up to 2.5 million years ago

Oldowan Complex

The stone tool culture associated with H. habilis and, possibly, A. garhi, including primitive chopper tools.

Australopithecus (or Kenyanthropus) platyops (3.5 mya)

-An australopithecine from East Africa that had a unique flat face and was contemporaneous with A. afarensis.

Tugen Hills, Kenya

one of the few areas in Africa preserving a succession of deposits from the period of between 14 and 4 million years ago, making them an important location for the study of human (and animal) evolution. Excavations at the site conducted by Richard Leakey and others have yielded a complete skeleton of a 1.5-million-year-old elephant (1967), a new species of monkey (1969) and fossil remains of hominids from 1 to 2 million years ago. Six million year old hominid fossils were discovered here in 2000 by Martin Pickford, the oldest ever discovered in Kenya, and the second oldest in the world after Sahelanthropus tchadensis. The species was named Orrorin tugenensis after the location.

chemical dating

Dating methods that use predictable chemical changes that occur over time.

Cenozoic

Is the most recent of the three classic geological eras and covers the period from 65.5 million years ago to the present.

Tim White

most famous for his work on Lucy as Australopithecus afarensis with discoverer Donald Johanson.

Australopithecus africanus (3-2 mya)

-A gracile australopithecine from South Africa that was contemporaneous with A. aethiopicus, A. garhi, and A. boisei and was likely ancestral to A. robustus. -anatomically similar to Au. afarensis, with a combination of human-like and ape-like features. Compared to Au. afarensis, Au. africanus had a rounder cranium housing a larger brain and smaller teeth, but it also had some ape-like features including relatively long arms and a strongly sloping face that juts out from underneath the braincase with a pronounced jaw. Like Au. afarensis, the pelvis, femur (upper leg), and foot bones of Au. africanus indicate that it walked bipedally, but its shoulder and hand bones indicate they were also adapted for climbing,

fluorine dating

A relative (chemical) dating method that compares the accumulation of fluorine in animal and human bones from the same site.

Characteristics of hominids that distinguish them from apes?

-hominids are exclusively terrestrial/none are arboreal -hominids have larger brains -hominids have smaller pelvic bones to support bipedalism -apes had very pronounced sagittal crests -larger diastema in apes due to larger canines -prominent brow ridges in apes -humans have far smaller canines -humans have thick enamal on teeth

Who are the pre-australopithecines?

the oldest hominids. Most often the remains of the preaustralopithecine species are fragmentary and possess both apelike and humanlike traits. These species were likely bipeds, one of the main features of hominids. The oldest species is Sahelanthropus tchadensis, a fossil found in central Africa, dating between seven and six million years ago. It had a small brain, roughly the size of modern apes. Orrorin tugenensis was discovered in East Africa and dates to six million years ago. It had curved phalanges, which suggest that while bipedal, Orrorin continued to use the trees. Ardipithecus kadabba and Ardipithecus ramidus were found in East Africa and date between 5.8 and 4.4 million years ago. These fossils also had curved phalanges, indicating continued use of the trees. All of the preaustralopithecines were found in wooded environments, were diverse, and were morphologically primitive.

Paleoclimate

the study of changes in climate taken on the scale of the entire history of Earth. It uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within (e.g.) rocks, sediments, ice sheets, tree rings, corals, shells and microfossils; it then uses these records to determine the past states of the Earth's various climate regions and its atmospheric system.

maxilla

upper jaw especially of humans and other mammals in which the bony elements are closely fused

Ardipithecus kadabba (5.8-5.6 mya)

-An early preaustralopithecine species from the late Miocene to the early Pliocene; shows evidence of a perihoning complex, a primitive trait intermediate between apes and modern humans. -was bipedal (walked upright), probably similar in body and brain size to a modern chimpanzee, and had canines that resemble those in later hominins but that still project beyond the tooth row. This early human species is only known in the fossil record by a few post-cranial bones and sets of teeth. One bone from the large toe has a broad, robust appearance, suggesting its use in bipedal push-off.

Australopithecus aethiopicus (2.5 mya)

-An early robust australopithecine from East Africa, with the hallmark physical traits of large teeth, large face, and massive muscle attachments on the cranium.

Australopithecus boisei (2.3-1.2 mya)

-Formerly known as Zinjanthropus boisei; a later robust australopithecine from East Africa that was contemporaneous with A. robustus and A. africanus and had the robust cranial traits, including large teeth, large face, and heavy muscle attachments.

dendrochronology

A chronometric dating method that uses a tree-ring count to determine numerical age.

Pangea

A hypothetical landmass in which all the continents were joined, approximately 300-200 mya.

Hadar, Ethiopia

A member of the 1973 expedition to Hadar, the archeologist Donald Johanson, returned to Hadar the next year to make the first discovery of the remains of Lucy, a three million year old fossilized specimen of Australopithecus afarensis. The name 'Lucy' was inspired by the song "Lucy in the Sky with Diamonds", by The Beatles, which happened to be playing on the radio at base camp. About thirty years later, another skeleton of an Australopithecus afarensis was found in another outcrop of the Hadar Formation across the Awash in Dikika. The skeleton was a three year old girl and afterwards named "Selam", which means peace in several Ethiopian languages.

Relative vs absolute dating methods

Absolute dating assigns an exact date to something where relative gives a time period.

fission track dating

An absolute dating method based on the measurement of the number of tracks left by the decay of uranium-238.

paleomagnetic dating

An absolute dating method based on the reversals of Earth's magnetic field.

amino acid dating

An absolute dating method for organic remains such as bone or shell, in which the amount of change in the amino acid structure is measured.

electron spin resonance dating

An absolute dating method that uses microwave spectroscopy to measure electrons' spins in various materials.

East Turkana, Kenya/Lake Turkana

Around two to three million years ago, the lake was larger and the area more fertile, making it a centre for early hominids. Richard Leakey has led numerous anthropological digs in the area which have led to many important discoveries of hominin remains. The two-million-year-old skull 1470 was found in 1972. It was originally thought to be Homo habilis, but the scientific name Homo rudolfensis, derived from the old name of the Lake Rudolf, was proposed in 1986 by V. P. Alexeev. In 1984, the Turkana Boy, a nearly complete skeleton of a Homo ergaster boy was discovered by Kamoya Kimeu. More recently, Meave Leakey discovered a 3.5 million-year-old skull there, named Kenyanthropus platyops, which means "the flat-faced man of Kenya".

biostratigraphic dating

Draws on the first appearance of an organism in the fossil record, that organism's evolutionary development over time, and the organism's extinction.

How does continental movement affect life and fossils?

It causes the climate to change on land masses which causes everything on that land mass to evolve and adapt to the new environment.

Limitations of fossil record?

It is in favor of marine organisms because those environments are the most likely to preserve organisms.

Olduvai Gorge Tanzania

Louis and Mary Leakey are often referred to as the first family of paleontology, as much of their lives, and later the lives of their children, revolved around Olduvai Gorge. The couple met on a dig in England, and both worked briefly at the Olduvai Gorge before being married in England in 1937. Louis was born in 1903 in Kenya, where his English parents were missionaries. He would often uncover prehistoric stone tools while he was out bird watching. After graduating from University in England, he joined a fossil-finding expedition to what is now Tanzania, which sparked his interest in human origins. In 1930s, the Leakeys found stone tools in Olduvai and elsewhere. Among their most notable finds were several extinct vertebrates, including the 25-million-year-old Pronconsul primate, one of the first and few fossil ape skulls discovered. Political unrest in nearby Kenya forced them to put their work on hold, but they went back to Olduvai Gorge in the late 1950s. While they had focused on tools in their previous work at the gorge, they went back to look for further evidence of human life. One day in 1959, Mary went out to work as usual, leaving Louis behind with a headache. She discovered fossilized parts of a skull and upper teeth of a type of hominin that had not been previously identified. Over the next several weeks, the Leakeys uncovered about 400 pieces of a nearly complete skull. There were similarities to other discoveries, including those in South Africa by Raymond Dart in 1924 and by Robert Broom in 1936. However, the Leakeys classified their find as new category of hominin, dubbing it Zinjanthropus boisei. It was not the direct ancestor of humankind that the Leakeys had hoped for, but it brought the couple some notoriety and spurred public interest in the study of human origins. They dated the discovery as having lived 1.75 million years ago. This made it the oldest hominin discovered to that point, although a lack of fossil-dating technology made it difficult to determine the age of Dart's and Broom's earlier finds. The combination of the works of the Leakeys, Dart and Broom made a convincing case that humans originally evolved in Africa. By 1960, Louis Leakey had become ill and Mary took over most of the operation. There were a number of developments during this period. They uncovered a well-preserved fossil foot that had arches, giving credence to the theory that hominins walked upright. During this time, Mary Leakey and son Jonathan found another, smaller form of hominin that they called Homo habilis, translated as "handy human," because it seemed he was able to use tools. This fossil was dated at about 2 million years old. This was confirmed when another son, Richard, discovered another Homo habilis in 1972. This 1972 discovery also supported the elder Leakey's theory that there were several lines of hominins developing simultaneously and that the Homo genus did not evolve from Australopithecus.

Acheulian Complex

The culture associated with H. erectus, including handaxes and other types of stone tools; more refined than the earlier Oldowan tools.

Sahelanthropus tchadensis

The earliest pre-australopithecine species found in central Africa with possible evidence of bipedalism.

pebble tools

The earliest stone tools, in which simple flakes were knocked off to produce an edge used for cutting and scraping.

Lower Paleolithic

The oldest part of the period during which the first stone tools were created and used, beginning with the Oldowan Complex.

isotopes

Two or more forms of a chemical element that vary in the number of neutrons in the nucleus and by the atomic mass.

Nonhoning cs. honing chewing

While humans have nonhoning chewing, primates such as gorillas have a honing complex, in which their large canines cut food. Upper canines are sharpened against the lower third premolar.

Laetoli, Tanzania

a site in Tanzania, dated to the Plio-Pleistocene and famous for its hominin footprints, preserved in volcanic ash (Site G). The site of the Laetoli footprints is located 45 km south of Olduvai gorge. The location was excavated by archaeologist Mary Leakey in 1978. "The Laetoli Footprints" received significant recognition by the public, providing convincing evidence of bipedalism in Pliocene hominids based on analysis of the impressions. Dated to 3.6 million years ago they were also the oldest known evidence of bipedalism at the time they were found, although now older evidence has been found such as the Ardipithecus ramidus fossils. The footprints and skeletal structure excavated at Laetoli showed clear evidence that bipedalism preceded enlarged brains in hominids. Although it is highly debated, it is believed the three individuals who made these footprints belonged to the species Australopithecus afarensis. Along with footprints were other discoveries including hominin and animal skeletal remains and Acheulean artifacts

obturator externus groove

the groove on the posterior neck of the femur for the insertion of the obturator externus muscle, a muscle that is important during bipedal locomotion. This landmark is used as evidence of bipedal locomotion in the hominins. The fossil Orrorin tugenensis (6-7 mya) possesses the obturator externus groove, which suggests that it moved bipedally and could represent one of the earliest fossils with evidence of bipedal locomotion.

Australopithecus garhi (2.5 mya)

-A late australopithecine from East Africa that was contemporaneous with A. africanus and A. aethiopicus and was the likely ancestor to the Homo lineage. -This species is not well documented; it is defined on the basis of 1 fossil cranium and 4 other skull fragments, although a partial skeleton found nearby, from about the same layer, is usually included as part of the Australopithecus garhi sample. The associated fragmentary skeleton indicates a longer femur (compared to other Australopithecus specimens, like 'Lucy') even though long, powerful arms were maintained. This suggests a change toward longer strides during bipedal walking.

Australopithecus robustus (2-1.5 mya)

-A robust australopithecine from South Africa that may have descended from A. afarensis, was contemporaneous with A. boisei, and had the robust cranial traits of large teeth, large face, and heavy muscle attachments.

homo habilis (2.5-1.8 mya)

-The earliest Homo species, a possible descendant of A. garhi and an ancestor to H. erectus; showed the first substantial increase in brain size and was the first species definitively associated with the production and use of stone tools. -This species, one of the earliest members of the genus Homo, has a slightly larger braincase and smaller face and teeth than in Australopithecus or older hominin species. But it still retains some ape-like features, including long arms and a moderately-prognathic face. -Its name, which means 'handy man', was given in 1964 because this species was thought to represent the first stone-tool maker. Currently, the oldest stone tools are dated slightly older than the oldest evidence of the genus Homo.

First hominid?

Sahelanthropus tchadensis 7-6 million years ago

Swartkrans, South Africa

Some of the earliest evidence of controlled use of fire by humans can be found at Swartkrans. [2] [3] Fossils discovered in the limestone of Swartkrans include Telanthropus capensis (a variety of Homo erectus), Paranthropus and Homo habilis Noted paleontologist Robert Broom was a frequent digger. He was followed by Charles Kimberlin Brain (C.K. 'Bob' Brain), whose excavations at the site inspired his book The Hunters or the Hunted? in which he demonstrated that instead of being bloodthirsty killer apes, the hominin fossils found at the site were themselves victims of predation by big cats. Swartkrans is part of the Cradle of Humankind World Heritage Site.

taphonomy

The study of the deposition of plant or animal remains and the environmental conditions affecting their preservation.

Who are the australopithecines?

a more recent group of hominids than the preaustralopithecines. There are at least seven distinct species, represented by hundreds of fossil remains. The fossils have been found in both East Africa and South Africa and are clearly bipedal with nonhoning chewing. They also have a range of variation in size and robusticity. The oldest australopithecine is Australopithecus anamensis, ancestor to Australopithecus afarensis. Australopithecus afarensis was ancestral to several other species, including Australopithecus africanus from South Africa and Australopithecus garhi, who made and used the first stone tools. Australopithecus platyops existed at the same time as Australopithecus afarensis, but had a much flatter face, a derived feature. A special group of australopithecines, the robust australopithecines, possessed a number of robust cranial and dental traits such as a sagittal crest and large posterior teeth. The robust australopithecines include Australopithecus aethiopicus, Australopithecus boisei, and Australopithecus robustus, a South African descendant of Australopithecus africanus.

post orbital constriction

a narrowing of the cranium (skull) just behind the eye sockets (the orbits, hence the name), in primates — including primitive hominids. This constriction is very noticeable in non-human primates, slightly less so in Australopithecines, even less in Homo erectus and the most primitive Homo sapiens. It completely disappears in modern Homo sapiens. Thus, it is a useful, quantifiable measure of how far along the evolutionary path a hominid fossil might be placed.

Donald Johanson

an American paleoanthropologist. Along with Maurice Taieb and Yves Coppens, he is known for discovering the fossil of a female hominid australopithecine known as "Lucy" in the Afar Triangle region of Hadar, Ethiopia.

5 characteristics associated with bipedalism?

-A diagnostic feature of bipedal locomotion is a shortened and broadened ilium; the australopithecine ilium is shorter than that of apes, and it is slightly curved; this shape suggests that the gluteal muscles were in a position to rotate and support the body during bipedal walking -In modern humans, the head of the femur is robust, indicating increased stability at this joint for greater load bearing -In humans, the femur angles inward from the hip to the knee joint, so that the lower limbs stand close to the body's midline. The line of gravity and weight are carried on the outside of the knee joint; in contrast, the chimpanzee femur articulates at the hip, then continues in a straight line downward to the knee joint -The morphology of the australopithecine femur is distinct and suggests a slightly different function for the hip and knee joints. The femoral shaft is angled more than that of a chimpanzee and indicates that the knees and feet were well planted under the body -In modern humans, the lower limbs bear all the body weight and perform all locomotor functions. Consequently, the hip, knee and ankle joint are all large with less mobility than their counterparts in chimpanzees. In australopithecines, the joints remain relatively small. In part, this might be due to smaller body size. It may also be due to a unique early hominid form of bipedal locomotion that differed somewhat from that of later hominids.

Australopithecus sediba (1-1.8 mya)

-A late species of australopithecine from South Africa that may have descended from A. africanus, was a contemporary of A. robustus, and expresses anatomical features found in Australopithecus and in Homo. -The fossil skeletons of Au. sediba from Malapa cave are so complete that scientists can see what entire skeletons looked like near the time when Homo evolved. Details of the teeth, the length of the arms and legs, and the narrow upper chest resemble earlier Australopithecus, while other tooth traits and the broad lower chest resemble humans. These links indicate that Au. sediba may reveal information about the origins and ancestor of the genus Homo. Functional changes in the pelvis of Au. sediba point to the evolution of upright walking, while other parts of the skeleton retain features found in other australopithecines. Measurements of the strength of the humerus and femur show that Au. sediba had a more human-like pattern of locomotion than a fossil attributed to Homo habilis. These features suggest that Au. sediba walked upright on a regular basis and that changes in the pelvis occurred before other changes in the body that are found in later specimens of Homo. The Australopithecus sediba skull has several derived features, such as relatively small premolars and molars, and facial features that are more similar to those in Homo. However, despite these changes in the pelvis and skull, other parts of Au. sediba skeleton shows a body similar to that of other australopithecines with long upper limbs and a small cranial capacity. The fossils also show that changes in the pelvis and the dentition occurred before changes in limb proportions or cranial capacity. The combination of primitive and derived traits in Australopithecus sediba shows part of the transition from a form adapted to partial arboreality to one primarily adapted to bipedal walking. but the legs and feet point to a previously unknown way of walking upright. With each step, Australopithecus sediba turned its foot inward with its weight focused on the outer edge of the foot. This odd way of striding may mean that upright walking evolved on more than one path during human evolution.

Ardipithecus ramidus (5.8-5.2 mya)

-A later preaustralopithecine species from the late Miocene to the early Pliocene; shows evidence of both bipedalism and arboreal activity but no indication of the primitive perihoning complex. -first reported in 1994; in 2009, scientists announced a partial skeleton, nicknamed 'Ardi'. The foot bones in this skeleton indicate a divergent large toe combined with a rigid foot - it's still unclear what this means concerning bipedal behavior. The pelvis, reconstructed from a crushed specimen, is said to show adaptations that combine tree-climbing and bipedal activity. The discoverers argue that the 'Ardi' skeleton reflects a human-African ape common ancestor that was not chimpanzee-like. A good sample of canine teeth of this species indicates very little difference in size between males and females in this species. -Ardi's fossils were found alongside faunal remains indicating she lived in a wooded environment. This contradicts the open savanna theory for the origin of bipedalism, which states that humans learned to walk upright as climates became drier and environments became more open and grassy.

How do anthropologists use fossils to describe paleoclimates?

-Air trapped within fallen snow becomes encased in tiny bubbles as the snow is compressed into ice in the glacier under the weight of later years' snow. -trees respond to changes in climatic variables by speeding up or slowing down growth, which in turn is generally reflected a greater or lesser thickness in growth rings -Sediments, sometimes lithified to form rock, may contain remnants of preserved vegetation, animals, plankton or pollen, which may be characteristic of certain climatic zones. -Coral "rings" are similar to tree rings, except they respond to different things, such as the water temperature and wave action. From this source, certain equipment can be used to derive the sea surface temperature and water salinity from the past few centuries.

Australopithecus afarensis (4-3 mya)

-An early australopithecine from East Africa that had a brain size equivalent to a modern chimpanzee's and is thought to be a direct human ancestor. -one of the longest-lived and best-known early human species—paleoanthropologists have uncovered remains from more than 300 individuals! Found between 3.85 and 2.95 million years ago in Eastern Africa (Ethiopia, Kenya, Tanzania), this species survived for more than 900,000 years, which is over four times as long as our own species has been around. It is best known from the sites of Hadar, Ethiopia ('Lucy', AL 288-1 and the 'First Family', AL 333); Dikika, Ethiopia (Dikika 'child' skeleton); and Laetoli (fossils of this species plus the oldest documented bipedal footprint trails). -Similar to chimpanzees, Au. afarensis children grew rapidly after birth and reached adulthood earlier than modern humans. This meant A. afarensis had a shorter period of growing up than modern humans have today, leaving them less time for parental guidance and socialization during childhood. -Au. afarensis had both ape and human characteristics: members of this species had apelike face proportions (a flat nose, a strongly projecting lower jaw) and braincase (with a small brain, usually less than 500 cubic centimeters -- about 1/3 the size of a modern human brain), and long, strong arms with curved fingers adapted for climbing trees. They also had small canine teeth like all other early humans, and a body that stood on two legs and regularly walked upright. Their adaptations for living both in the trees and on the ground helped them survive for almost a million years as climate and environments changed.

How are fossils created?

-Freezing, drying and encasement, such as in tar or resin, can create whole-body fossils that preserve bodily tissues. These fossils represent the organisms as they were when living, but they're very rare. -The heat and pressure from being buried in sediment can sometimes cause the tissues of organisms — including plant leaves and the soft body parts of fish, reptiles and marine invertebrates — to release hydrogen and oxygen, leaving behind a residue of carbon. This process — which is called carbonization, or distillation — yields a detailed carbon impression of the dead organism in sedimentary rock. -The most common method of fossilization is called permineralization, or petrification. After an organism's soft tissues decay in sediment, the hard parts — particularly the bones — are left behind. -In another fossilization process, called replacement, the minerals in groundwater replace the minerals that make up the bodily remains after the water completely dissolves the original hard parts of the organism.

Australopithecus anamensis (4 mya)

-The oldest species of australopithecine from East Africa and a likely ancestor to A. afarensis. -has a combination of traits found in both apes and humans. The upper end of the tibia (shin bone) shows an expanded area of bone and the orientation of the ankle joint in human-like, indicative of regular bipedal walking (support of body weight on one leg at the time). Long forearms and features of the wrist bones suggest these individuals probably climbed trees as well.

foramen magnum

-a large opening in the occipital bone of the cranium. It is one of the several oval or circular apertures in the base of the skull (the foramina), through which the medulla oblongata (an extension of the spinal cord) enters and exits the skull vault. -n humans, the _________________ is farther underneath the head than in great apes. Thus, in humans, the neck muscles (including the occipitofrontalis muscle) do not need to be as robust in order to hold the head upright. Comparisons of the position of the______________in early hominid species are useful to determine how comfortable a particular species was when walking on two limbs (bipedalism) rather than four (quadrupedalism).

Middle Awash, Ethiopia

A number of Pleistocene and late Miocene hominid remains have been found at the site,[1] along with some of the oldest known Olduwan stone artifacts[2] and patches of fire-baked clay, disputed evidence of the use of fire.[3] Chimpanzee and human lineages are thought to have split around this time, somewhere between 5 million and 7 million years ago.[4] Sediments at the site were originally deposited in lakes or rivers, and carbonates found there contain low carbon isotope ratios. This information suggests that, in contrast to the aridity of the current climate, the environment of the Middle Awash during the late Miocene was wet, and the region was occupied by woodland or grassy woodland habitats. The fossilized remains of vertebrates found with the hominids, including the cane rat, further suggest such an environment.[4] The region was also the site of periodic volcanism. This rifting probably created distinct ecological regions inhabited by different species of vertebrate animals.[5] Important hominid fossils found in the Middle Awash include:[5][6] Ardipithecus kadabba Ardipithecus ramidus Australopithecus afarensis Australopithecus garhi Australopithecus anamensis Homo erectus Homo sapiens idaltu found at Herto Bouri.

Orrorin tugenensis (6 mya)

A preaustralopithecine species found in East Africa that displayed some of the earliest evidence of bipedalism. Living around 6 million years ago, Orrorin tugenensis is the one of the oldest early humans on our family tree. Individuals of this species were approximately the size of a chimpanzee and had small teeth with thick enamel, similar to a modern human's. The most important fossil of this species is an upper femur, showing evidence of bone buildup typical of a biped - so Orrorin tugenensis individuals climbed trees but also probably walked upright with two legs on the ground.

thermoluminesence dating

A relative dating method in which the energy trapped in a material is measured when the object is heated.

sagittal keel

A slight ridge of bone found along the midline sagittal suture of the cranium, which is typically found on H. erectus skulls.

First Family (333)

AL 333, commonly referred to as the "__________", is a collection of prehistoric hominid teeth and bones. Discovered in 1975 by Donald Johanson's team in Hadar, Ethiopia, the "__________" is estimated to be about 3.2 million years old and consists of the remains of at least thirteen individuals. They are generally thought to be members of the species Australopithecus afarensis. There are multiple theories about the hominids' cause of death and some debate over their species and sexual dimorphism.

homo erectus

An early Homo species and the likely descendant of H. habilis; the first hominid species to move out of Africa into Asia and Europe. Early African Homo erectus fossils (sometimes called Homo ergaster) are the oldest known early humans to have possessed modern human-like body proportions with relatively elongated legs and shorter arms compared to the size of the torso. These features are considered adaptations to a life lived on the ground, indicating the loss of earlier tree-climbing adaptations, with the ability to walk and possibly run long distances. Compared with earlier fossil humans, note the expanded braincase relative to the size of the face. The most complete fossil individual of this species is known as the 'Turkana Boy' - a well-preserved skeleton (though minus almost all the hand and foot bones), dated around 1.6 million years old. Microscopic study of the teeth indicates that he grew up at a growth rate similar to that of a great ape. There is fossil evidence that this species cared for old and weak individuals. The appearance of Homo erectus in the fossil record is often associated with the earliest handaxes, the first major innovation in stone tool technology. Early fossil discoveries from Java (beginning in the 1890s) and China ('Peking Man', beginning in the 1920s) comprise the classic examples of this species. Generally considered to have been the first species to have expanded beyond Africa, Homo erectus is considered a highly variable species, spread over two continents (it's not certain whether it reached Europe), and possibly the longest lived early human species - about nine times as long as our own species, Homo sapiens, has been around!

index fossils

Fossils that are from specified time ranges, are found in multiple locations, and can be used to determine the age of associated strata.

Where are we in earth's history today(the time period on the geologic time scale)?

Holocene Epoch

Sterkfontein, South Africa

In 1936, the Sterkfontein caves yielded the first adult Australopithecine, substantially strengthening Raymond Dart's claim that the skull known as the Taung child (an Australopithecus africanus) was a human ancestor. There was a pause in excavation during World War II, but after the war Dr. R. Broom continued excavations. In 1947 he found the almost complete skull of an adult female (http://en.wikipedia.org/wiki/STS_5 STS 5) A. africanus (or possibly that of an adolescent male). Robert Broom initially named the skull Plesianthropus transvaalensis (near-man from Transvaal), but it became better known by its nickname, Mrs. Ples. Mrs Ples is now defined as a member of A. africanus. In 1997, a near complete skeleton of a second species of Australopithecus (StW 573) was found in the caves by Ronald J. Clarke; extraction of the remains from the surrounding breccia is ongoing. The skeleton was named Little Foot, since the first parts found (in 1995, in storage) were the bones of a foot. Excavations continue to this day and finds now total some 500 hominids, making Sterkfontein one of the richest site in the world for early hominids.

Martin Pickford/Brigitte Senut

In 2001 _____________ together with ______________ and their team discovered Orrorin tugenensis, a hominid primate species dated between 5.8 and 6.2 million years ago and a potential ancestor of the Australopithecus genus.[3]

cultural dating

Relative dating methods that are based on material remains' time spans.

Lucy

One of the most significant fossils: the 40% complete skeleton of an adult female A. afarensis, found in East Africa.

Taung Child/Taung, South Africa

The ___________ is among the most important early human fossils ever discovered. It was the first hominid to be discovered in Africa, a species later named Australopithecus africanus, supporting Charles Darwin's concepts that the closest living relatives of humans are the African apes. It furthermore demonstrated significant differences between reality and the fake skull of a proposed human ancestor from England known as the Piltdown Man or Eoanthropus. The little skull is hypothesized to be from an approximately three to three and a half year old child. -It was discovered in 1924 by quarrymen working for the Northern Lime Company in Taung, South Africa. Raymond Dart described it as a new species in the journal Nature in 1925

racemization

The chemical reaction resulting in the conversion of L amino acids to D amino acids for amino acid dating.

What are fossils?

The preserved remains/traces of animals, plants, and organisms from the past.

Steno's law of superposition

The principle that the lower the stratum or layer, the older its age; the oldest layers are at the bottom, and the youngest are at the top.

stratigraphic correlation

The process of matching up strata from several sites through the analysis of chemical, physical, and other properties.

radiocarbon dating

The radiometric dating method in which the ratio of 14C to 12C is measured to provide an absolute date for a material younger than 50,000 years.

radio potassium dating

The radiometric dating method in which the ratio of 40K to 40Ar is measured to provide an absolute date for a material older than 200,000 years.

Malapa, South Africa

The site has produced arguably one of the most complete assemblages of early human ancestors ever found, including arguably the most complete skeletons of early hominids yet discovered, and by far the most complete remains of any hominid dating to around 2 million years ago.[3] Over 200 elements have been recovered to date.[3] The partial skeletons are initially described in two papers in the journal Science by Berger and colleagues as a new species of early human ancestor called Australopithecus sediba (sediba meaning natural spring or well in Sotho).[3] In addition to the fossils revealed initially, rocks collected from the site have been examined with CT scans and contain even more bones, suggesting that the type specimen, Karabo, will become even more complete. [4] The species is suggested by the authors to be a good candidate for being the transitional species between the southern African ape-man Australopithecus africanus (the Taung Child, Mrs. Ples) and either Homo habilis or even a direct ancestor of Homo erectus (Turkana boy, Java man, Peking man).[5] The species has long arms, like an ape, short powerful hands, a very advanced pelvis and long legs capable of striding and possibly running like a human.

Meave Leakey

__________'s research team at Lake Turkana, Kenya made a discovery in 1999 that completely changed the understanding of early human ancestry. They found a 3.5-million-year-old skull and partial jaw thought to belong to a new branch of the early human family. She named the find Kenyanthropus platyops, or flat-faced man of Kenya.

Cradle of Humankind

a World Heritage Site first named by UNESCO in 1999, about 50 kilometres northwest of Johannesburg, South Africa in the Gauteng province. This site currently occupies 47,000 hectares (180 sq mi); it contains a complex of limestone caves, including the Sterkfontein Caves, where the 2.3-million year-old fossil Australopithecus africanus (nicknamed "Mrs. Ples") was found in 1947 by Dr. Robert Broom and John T. Robinson. The find helped corroborate the 1924 discovery of the juvenile Australopithecus africanus skull, "Taung Child", by Raymond Dart, at Taung in the North West Province of South Africa, where excavations still continue. The name Cradle of Humankind reflects the fact that the site has produced a large number, as well as some of the oldest, hominin fossils ever found, some dating back as far as 3.5 million years ago. Sterkfontein alone has produced more than a third of early hominid fossils ever found.

Piltdown Man

a hoax in which bone fragments were presented as the fossilised remains of a previously unknown early human. These fragments consisted of parts of a skull and jawbone, said to have been collected in 1912 from a gravel pit at Piltdown, East Sussex, England. The Latin name Eoanthropus dawsoni ("Dawson's dawn-man", after the collector Charles Dawson) was given to the specimen. The significance of the specimen remained the subject of controversy until it was exposed in 1953 as a forgery, consisting of the lower jawbone of an orangutan deliberately combined with the skull of a fully developed modern human. The Piltdown hoax is perhaps the most famous paleoanthropological hoax ever to have been perpetrated. It is prominent for two reasons: the attention paid to the issue of human evolution, and the length of time (more than 40 years) that elapsed from its discovery to its full exposure as a forgery.

Occipital torus/bun

a prominent bulge, or projection, of the occipital bone at the back of the skull. Occipital buns are important in scientific descriptions of classic Neanderthal crania. While common among many of humankind's ancestors, primarily robust relatives rather than gracile, the protrusion is relatively rare in modern Homo sapiens.

carbon 14 dating

a radiometric dating technique that uses the decay of carbon-14 (14 C) to estimate the age of organic materials, such as wood and leather, up to about 58,000 to 62,000 years Before Present (BP, present defined as 1950). Carbon dating was presented to the world by Willard Libby in 1949, for which he was awarded the Nobel Prize in Chemistry. Since the introduction of __________, the method has been used to date many items, including samples of the Dead Sea Scrolls, the Shroud of Turin, enough Egyptian artifacts to supply a chronology of Dynastic Egypt,[2] and Ötzi the Iceman.

Rift Valley, Africa

a rich source of fossils that allow the study of human evolution. Because the rapidly eroding highlands have filled the valley with sediments, a favorable environment for the preservation of remains has been created. The bones of several hominid ancestors of modern humans have been found here, including those of "Lucy",[6] a partial, yet eye-opening australopithecine skeleton discovered by anthropologist Donald Johanson and dating back over 3 million years. Richard and Mary Leakey have done significant work in this region also.

Aramis, Ethiopia

a village and archaeological site in northeastern Ethiopia, where remains of Australopithecus and Ardipithecus (Ardipithecus ramidus) have been found. In 1992 and 1993 a team led by Tim White found in total 17 specimens of hominid fossils at Aramis. These fossils were dated at 4.4 million years, 500,000 years earlier than the oldest afarensis fossils found in the eastern Middle Awash. This discovery was published on the front page of New York Times, and later a new genus and species of hominids was proposed, Ardipithecus ramidus.[1]

Raymond Dart

best known for his involvement in the 1924 discovery of the first fossil ever found of Australopithecus africanus, an extinct hominid closely related to humans, at Taung in the North of South Africa in the province Northwest.

stratigraphy

branch of geology which studies rock layers and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks.

sahelanthropus tchadensis (7-6 mya)

one of the oldest known species in the human family tree. This species lived sometime between 7 and 6 million years ago in West-Central Africa (Chad). Walking upright may have helped this species survive in diverse habitats, including forests and grasslands. Although we have only cranial material fromSahelanthropus, studies so far show this species had a combination of apelike and humanlike features. Apelike features included a small brain (even slightly smaller than a chimpanzee's), sloping face, very prominent brow ridges, and elongated skull. Humanlike features included small canine teeth, a short middle part of the face, and a spinal cord opening underneath the skull instead of towards the back as seen in non-bipedal apes. How do we know Sahelanthropus walked upright? Some of the oldest evidence of a humanlike species moving about in an upright position comes from Sahelanthropus. The large opening (foramen magnum) where the spinal cord exits out of the cranium from the brain is located further forward (on the underside of the cranium) than in apes or any other primate except humans. This feature indicates that the head of Sahelanthropus was held on an upright body, probably associated with walking on two legs.

What are the two traits that define "hominid"?

refers to humans and human ancestors. In particular, hominids are a group of primates with two important features: bipedalism and non-honing chewing. While modern humans possess other unique traits, such as spoken language, advanced cognition, and complex culture, not all human ancestors possessed these. Bipedalism involves a variety of changes to the skeleton, including a shifting of the foramen magnum from the back of the skull in quadrupeds to the front of the skull. In addition, bipeds have longer legs and feet with two arches. The pelvis of bipeds is much shorter from front to back than in quadrupeds, and the big toe is no longer opposable. Nonhoning chewing is characterized by a number of changes in the dentition. First, the canines are smaller and nonprojecting, and much more blunt. In addition, there is no longer a diastema between the canine and lateral incisor. Nonhoning chewing also changes the pattern of wear on the teeth. Instead of wear on the back of the canine, hominids show wear on the tips of the canines and the third premolars. Lastly, the cusps of the third premolar are equal in size.

Louis Leakey

was a British archaeologist and naturalist whose work was important in establishing human evolutionary development in Africa, particularly through his discoveries in the Olduvai Gorge. He also played a major role in creating organizations for future research in Africa and for protecting wildlife there. Having been a prime mover in establishing a tradition of palaeoanthropological inquiry, he was able to motivate the next generation to continue it, notably within his own family, many of whom also became prominent. Leakey participated in national events of British East Africa and Kenya during the 1950s.