Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

55 Cards in this Set

  • Front
  • Back
To progress by swinging from hold to hold by the arms <a brachiating gibbon>
The original hominoid brachiators probably used typical terrestrial quadrupedalism as their alternate mode of ground locomotion. The development of knuckle walking made possible a shortening of the flexor muscles to improve the hand grip for more efficient arm-swinging. Bipedalism equally served to free the hands from palmar application to the ground, and likewise permits manual flexor shortening. Recently discovered australopithecine limb bones may be interpreted as indicating a primarily arboreal adaptation, emphasizing brachiation, with bipedalism being no more than an alternate mode.
Suspensory hanging
Suspensory Behavior, exhibited by primates, is a form of arboreal locomotion or a feeding behavior which involves hanging or suspension of the body below or among the branches, rather than moving or sitting on top of the branches. This includes brachiation, climbing, and bridging, and allows larger species to distribute their weight among smaller branches rather than balancing above these weak supports. Ruffed lemurs, sifakas, spider monkeys, gibbons, and orangutans are examples of primates that exhibit suspensory behaviors.
Knuckle-walking=form of quadrupedal walking
The forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles.
Gorillas and chimpanzees use this style of locomotion Anthropologists once thought that the common ancestor of chimpanzees and humans engaged in knuckle-walking, and humans evolved upright walking from knuckle-walking: a view supported by reanalysis of overlooked features on hominid fossils. Since then, scientists discovered Ardipithecus ramidus, a human-like hominid descended from the common ancestor of chimpanzees and humans. Ar. ramidus engaged in upright walking, but not knuckle-walking. This leads scientists to conclude that chimpanzees and apes evolved knuckle-walking after they split from humans 6 million years ago, and humans evolved upright walking without knuckle-walking.
In biology, a pair bond is the strong affinity that develops in some species between the males and/or females in a pair, potentially leading to breeding.The term often implies either a lifelong socially monogamous relationship or a stage of mating interaction in socially monogamous species. It is sometimes used in reference to human relationships.
The most common social group pattern among semi-terrestrial primates is the multimale-multifemale group. With this pattern, there are no stable heterosexual bonds--both males and females have a number of different mates. This is characteristic of savanna baboons, macaques, as well as some colobus and New World monkey species.

Multimale-multifemale groups commonly have a dominance hierarchy among both males and females. Each individual is ranked relative to all other community members of the same gender. This tends to reduce serious violence within the community since everyone knows in advance who they must defer to and who must be submissive to them. Among rhesus macaques, one's position in the dominance hierarchy is determined by the rank of his or her mother. Primate Species Following This Pattern:savanna baboons, macaques, colobus, and some New
World monkeys
One-male-several-female group. Primate Species following this Pattern: hamadryas baboons, geladas, langurs, howler monkeys,
gorillas, and some humans.Many primate species live in groups consisting of a single adult male along with several females and their offspring. Adult males not living with females form separate bands (all-male) or live alone as bachelors. The one-male groups are almost invariably characterized by repeated efforts by outside males to takeover the position of the resident male. In many instances, dependent infants are killed as a result of a change in the status of a resident male. Competition is high in the one-male society.
Some primate species exhibit a solitary social organization. Among several ecological and biological parameters that have been forwarded as correlates of a solitary lifestyle, a nocturnal activity cycle is considered an important determinant. Mostly, primates are social animals. Most mammals aren't. Holdouts, as usual, are the prosimians many of whom are solitary.
Vertical clinging and leaping
A type of arboreal locomotion seen most commonly among the strepsirrhine primates(medium to large sized lemurs who live exclusively on the island of Madagascar), and particularly the members of the family Indriidae. At rest, the animal clings to a vertical support, such as the side of a tree or bamboo stalk. To move from one plant to another, it pushes off from one vertical support with its hindlimbs, landing on another vertical support.
Arboreal Quadrupedalism
Mode of locomotion in which the animal moves along the horizontal branches with a regular gait pattern involving all four limbs.
Terrestrial Quadrupedalism
Four-limbed locomotion on the ground. Most primates are primarily arboreal, a few regularly walk and run on the ground. This type of locomotion is common among the OWMs (Old World Monkeys), such as baboons.
They have much shorter fingers and toes and their forelimbs and hindlimbs are similar in length. The tails of many terrestrial quadrupeds are also shorter than those of their arboreal relatives.
The australopithecines were the first primate to be bi-pedal, which is walking on two feet. The australopithecine footprints that Mary Leakey found in Laetoli Tanzania. These footprints confirmed the development of bipedalism in the australopithecines.
A form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs.
Primate traits
1) A shortened snout that contains at least three types of teeth.
2) Eye Sockets (orbits) that face forward and are protected on the side, toward the back, by bone (post-orbital bar).
3) Three little bones of the middle ear housed within an outgrowth (pestrosal bulla) of the skull, instead of being contained in a seperate bone.
4) Collar bones (clavical bones).
5) Fingernails and toenails instead of claws.
6) Two seperate bones in the forearm (radius and ulna) and leg (tibia and fibula).
7) Grasping feet (except for humans) and hands, with mobility of thumbs and big toes as well as other individual digits.
8) Tendency toward vertical posture.
9) Trend toward longer lives with longer periods of infancy, childhood, and adulthood.
10) Enlarged Brains with increased areas for seeing and decreased areas for smelling.
Nickname for a remarkably complete (40 percent intact) hominin skeleton found by Donald Johanson at Hadar, Ethiopia (East Africa), on Nov. 24, 1974, and dated to 3.2 million years ago. The specimen is usually classified as Australopithecus afarensis and suggests—by having long arms, short legs, an apelike chest and jaw, and a small brain but a relatively humanlike pelvis—that bipedal locomotion preceded the development of a larger (more humanlike) brain in hominin evolution. Lucy stood about 3 feet 7 inches (109 cm) tall and weighed about 60 pounds (27 kg). Australopithecus afarensis is a hominid which lived between 3.9 to 3 million years ago belonging to the genus Australopithecus, of which the first skeleton was discovered on November 24, 1974 by Donald Johanson, Yves Coppens and Tim White in the Middle Awash of Ethiopia's Afar Depression.

One of the most striking characteristics about Lucy was that she had a small skull, bipedal knee structure, and molars and front teeth of human (rather than great ape) style and relative size, but a small skull and small body. The image of a bipedal hominid with small skull, but teeth like a human, was quite a revelation to the paleoanthropological world at the time.
Robust australopithecines
The robust australopithecines, members of the extinct hominin genus Paranthropus (Greek para "beside", Greek anthropos "human"), were bipedal hominids that probably descended from the gracile australopithecine hominids (Australopithecus).
Species of Australopithecus that had very large back teeth, cheekbones, and faces, among other anatomical adaptations to heavy chewing. They lived in Africa between 2.5 million and 1.2 mil-lion years ago. Three species are generally recognized: A. aethiopicus, A. robustus, and A. boisei.
Gracile australopithecines
The gracile australopithecines inhabited Africa between 4 and 2 Million years ago (Ma). Our own genus, Homo, descended from one of the gracile Australopithecus species.
The australopithecines are generally divided into two groups – the gracile australopithecines and the robust australopithecines. The robust australopithecines are assigned their own genus by some researchers (Paranthropus) to distinguish them from the gracile australopithecines.
Gracile australopiths shared several traits with modern apes and humans, and were widespread throughout Eastern and Northern Africa around 3.5 million years ago. The earliest evidence of fundamentally bipedal hominids can be observed at the site of Laetoli in Tanzania. This site contains hominid footprints that are remarkably similar to those of modern humans and have been dated to as old as 3.6 million years.
Australopithecus afarensis
An extinct hominid that lived between 3.7 and 2.9 million years ago. (Gracile)
A. afarensis was slenderly built, like the younger Australopithecus africanus. It is thought that A. afarensis was ancestral to both the genus Australopithecus and the genus Homo, which includes the modern human species, Homo sapiens. The most famous fossil is the partial skeleton named Lucy (3.2 million years old)
A anamensis
Australopithecus anamensis (or Praeanthropus anamensis) is a stem-human species that lived approximately four million years ago. Nearly one hundred fossil specimens are known from Kenya and Ethiopia, representing over 20 individuals.
A boisei
The most striking feature of the A. boisei specimens is the degree of megadontia. This species has the absolute largest teeth found in any hominid group, with teeth similar in size to gorillas (who weigh as much as 10 times as much). They are often referred to as hyper-robust due to the massive postcanine megadontia. The features of boisei are best described in relation to the other "robusts" (including aethiopicus), since this best shows some of the features that exclude aethiopicus from the "robust" lineage in favor of africanus. Features that line up boisei as a descendent of africanus rather than aethiopicus include:

The face is more vertically set, more orthognathic (variability in this trait).
There is anterior teeth reduction.
There is a continued increase in postcanine teeth size.
There is a larger cranial capacity (500-550 cc).
The sagittal crest is on the mid-brain case, not the posterior.

Specimens attributed to A. boisei have been found mostly in Ethiopia, Tanzania, and Kenya in East Africa. The oldest has been found at Omo, Ethiopia, dating to approximately 2.3 myr (L. 74a-21), and the youngest has been found at Olduvai Gorge, dating to approximately 1.2 myr (OH 3 and OH 38).A. boisei seems to be the end point of a lineage that that was adapted to high masticatory stress needed to deal with hard low-quality foods. This species is sometimes called "hyper-robust" due to the relative and absolute size of their postcanines. This lineage may have died out due to overspecialization to a specific environment, and when the environment changed, evolution could not keep up. This seems to be the generally accepted idea regarding boisei, and there seems little hard evidence to contradict it.
Australopithecus boisei is an important species both in the history of paleoanthropological research and in constructing the phylogeny of the hominid lines. The features it shares or lacks with contemporary and earlier species makes relatively clear the relative phylogeny of the "robust" australopithecines. It also is present at a time when stone tools become much more common, and may have even made and used some. In the end, however, it seems that boisei became too specialized, and died with climatic and/or environmental shifts.
A robustus
The species name "robustus" was chosen to describe the skull, jaw, and teeth, which were much more dense and thicker than what was seen in previous species. There were also many more ridges and crests located on the skull. Its front teeth were smaller, but the molars in the back were larger than previous species. This trend is continually seen throughout the human evolution cycle. These dental characteristic hint that their diet consisted of tough foods that required a lot of grinding and chewing from those lower molars. A new advancement in the Australopithecus robustus was the presence of a "sagittal crest". This is a ridge that runs from front to back on top of the skull in which muscles are attached. These muscles aid in moving the jaw so that chewing is possible. As more muscle is formed more powerful chewing is possible.
-Ardipithecus ramidus
-Australopithecus afarnensis
A aethiopicus
Australopithecus aethiopicus may be an ancestor of two later species, Australopithecus robustus and Australopithecus boisei. The species has a peculiar mixture of primitive and highly derived traits relative to earlier species.

Brain size of A. aethiopicus is comparable to that of modern apes and the much-earlier A. afarensis. Other skull traits appear to be novel adaptations, some of which probably allowed A. aethiopicus to exploit tougher food sources. The massive face was flat or concave with no forehead.

A very large sagittal crest (a ridge of bone running along the top of the skull) and other heavily reinforced areas of the skull would have provided strong points of attachment for chewing muscles. Powerful chewing muscles, paired with the species' extremely large and thickly enameled molars and premolars, suggest that A. aethiopicus ate very tough, grainy foods that required a great deal of processing.

Fossil Finds:
The Black Skull
Estimated age: 2.6 million years
Date of discovery: 1984
Location: Lake Turkana, Kenya
This cranium, with its mix of primitive and advanced characteristics, is described by some as a nearly perfect intermediate between A. afarensis and A. boisei. The fossil suggests that A. aethiopicus was a transitional species.
A garhi
(2.5 million years ago)
Species Description:
Australopithecus garhi may represent an evolutionary link between the genera of Australopithecus and Homo. Circumstantial evidence suggests that A. garhi may have been the earliest tool user. Antelope fossils excavated from the same site as A. garhi show cut marks made by a stone tool; both the hominid and antelope fossils are dated at 2.5 million years old. The earliest stone tools, thought to be 2.6 million years old, were found nearby in Gona, Ethiopia.

Fossil Finds:
Estimated age: 2.5 million years
Date of discovery: 1997
Location: Bouri Formation, Ethiopia
The very large teeth in this partial skull suggest that A. garhi may have descended from one of the other Australopithecus species, likely A. afarensis.

Evidence of Culture:
Earliest stone tools (debated)
Estimated age: 2.5 million years
Location: Gona, Ethiopia
While the issue is debated, some scientists propose that A. garhi made tools by chipping small pieces off of volcanic rocks to form a sharp, scalloped edge.
A africanus
(3 to 2 million years ago)
Species Description: Australopithecus africanus was nearly identical in body and brain size to A. afarensis. Like A. afarensis, A. africanus also showed marked differences in size between males and females (sexual dimorphism). Although the teeth and jaws of A. africanus were much larger than modern human teeth, they are still more similar to ours than to the teeth of apes. The upper and lower jaws of A. africanus were also fully rounded in front, like those of modern humans, and their canine teeth were smaller on average than those of A. afarensis. Australopithecus africanus individuals probably inhabited open woodlands, where they would have foraged for fruits, seeds, and roots.
Fossil Finds:
Taung Child; estimated age: 3 to 2 million years; date of discovery: 1924
Location: Taung, South Africa
Collected by workers in a lime quarry, this was the first Australopithecus fossil ever discovered. The scientific community initially rejected the identification of this partial skull, saying that it was some sort of extinct ape species rather than an early form of hominid.
Mrs. Ples
Estimated age: 3 to 2 million years
Date of discovery: 1947
Location: Sterkfontein, South Africa
This adult cranium, most likely from a female A. africanus, is the best specimen of the species discovered so far.
STS 14
Estimated age: 3 to 2 million years
Date of discovery: 1947
Location: Sterkfontein, South Africa
These remains of a small adult female include a nearly complete vertebral column, a pelvis, some rib fragments, and part of a femur. The pelvis is far more humanlike than apelike and is strong evidence that A. africanus was bipedal.
Sahelanthropus tchadensis
Extinct hominid species that is dated to about 7 million years ago. Whether it can be regarded as part of the Hominina tree is unclear; there are arguments both supporting and rejecting it. Another complication in its classification is that it is older than the human-chimpanzee divergence (estimated to 6.3 to 5.4 million years ago) seen in genetic data, and that there are few if any specimens other than the partial cranium known as Toumaï. The fossils were discovered in the Djurab desert of Chad.
Sahelanthropus may represent a common ancestor of humans and chimpanzees; no consensus has been reached yet by the scientific community. The original placement of this species as a human ancestor but not a chimpanzee ancestor would complicate the picture of human phylogeny. In particular, if Toumaï is a direct human ancestor, then its facial features bring the status of Australopithecus into doubt because its thickened brow ridges were reported to be similar to those of some later fossil hominids (notably Homo erectus), whereas this morphology differs from that observed in all australopithecines, most fossil hominids and extant humans.
Central Africa=Chad: While molecular clocks are increasingly found to be far more unreliable than initially believed sediment isotope analysis which yielded an age of about 7 million years is generally considered quite reliable. In this case however, the fossils were found exposed in loose sand; co-discoverer Beauvilain cautions that such sediment can be easily moved by the wind, unlike packed earth.
In fact, Toumaï was probably reburied in the recent past. Taphonomic analysis reveals the likelihood of one, perhaps two, burial(s) which seemingly occurred after the introduction of Islam in the region. Two other hominid fossils (a left femur and a mandible) were in the same “grave” along with various mammal remains.The sediment surrounding the fossils might thus not be the material the bones were originally deposited in, making it necessary to corroborate the fossil's age by some other means.
The fauna found at the site – namely the anthracotheriid Libycosaurus petrochii and the suid Nyanzachoerus syrticus – suggests an age of more than 6 million years, as these species were probably extinct already by that time.
Orrorin tugenensis
Considered to be the second-oldest (after Sahelanthropus) known hominin ancestor that is possibly related to modern humans, and it is the only species classified in genus Orrorin. Orrorin is significant because it can be an early bipedal hominin.

The name was given by the discoverers who found Orrorin fossils in the Tugen Hills of Kenya (lies across the equator on the east coast of Africa/The Great Rift Valley bisects the Kenya Highlands into east and West). By analysing radiometric decay (K–Ar dating), paleomagnetism, and biochronology the age of the specimen have been estimated to 6 to 5.8 million years (Ma) (average: 6.1 Ma). At present, 20 fossils have been found at four sites in the Lukeino Formation: of these, the fossils at Cheboit and Aragai are the oldest (6.1 Ma), while those in Kapsomin and Kapcheberek are found in the upper levels of the formation (5.7 Ma).
Ardipithecus ramidus
Ardipithecus is a very early hominin genus. Two species are described: A. ramidus, which lived about 4.4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago (late Miocene). A. ramidus was named in September 1994. The first fossil find was dated to 4.4 million years ago based on its interval between two volcanic strata. The name Ardipithecus ramidus stems mostly from the Afar language, in which Ardi means "ground/floor" and ramid means "root". The pithecus portion of the name is from the Greek word for "ape".
Its distinguishing characteristics are bipedalism incorporating an arboreal grasping hallux or big toe, reduced canine teeth and a smaller brain size comparable to that of the modern chimpanzee.In 1992–1993 a research team headed by Tim White discovered the first A. ramidus fossils—seventeen fragments including skull, mandible, teeth and arm bones—from the Afar Depression in the Middle Awash river valley of Ethiopia. More fragments were recovered in 1994, amounting to 45% of the total skeleton.
Extinct hominin genus Paranthropus (Greek para "beside", Greek anthropos "human").
All species of Paranthropus were bipedal, and many lived during a time when species of the genus Homo (which were possibly descended from Australopithecus), were prevalent. Paranthropus first appeared roughly 2.7 million years ago. Most species of Paranthropus had a brain about 40 percent of the size of a modern human. A partial cranium and mandible of Paranthropus robustus was discovered in 1938 by a schoolboy, Gert Terblanche, at Kromdraai B (70 km south west of Pretoria) in South Africa. It was described as a new genus and species by Robert Broom of the Transvaal Museum. The site has been excavated since 1993 by Francis Thackeray of the Transvaal Museum. A date of at least 1.95 million years has been obtained for Kromdraai B.
Paranthropus boisei was discovered by Mary Leakey on July 17, 1959, at the FLK Bed I site of Olduvai Gorge in Tanzania (specimen OH 5).
Central Africa
Sahelanthropus tchadensis, was found close to the western Djurab desert of northern Chad in central Africa. The fossil is significant to Darwinists for the following reasons: (1) Most evolutionists believe that human origins began in Eastern and / or Southern Africa and this is the first and oldest fossil of its kind to be found in the central portion of the African continent -- (2) Most evolutionists believe that humans and chimpanzees split from a common ancestor about 5 million years ago so a 7 million-year-old fossil challenges this opinion -- (3) The authors say this fossil has characteristics that are not associated with many of the most ancient australopithecines.A nearly complete cranium was discovered in 2001 at the Toros-Menalla site in northern Chad (Brunet et al., 2002). Provisionally dating using faunal correlation suggests a date of nearly 7 m.y.a. (Vignaud et al., 2002). This very early suggested age of the fossil has proved a major surprise, dating almost one million years earlier than any of the other proposed early hominids (and close to three million years older than the oldest well-established hominid discoveries). The location of the find was also quite unexpected, as it is a full 1500 miles west of the well-known and extremely productive areas in East Africa -- long thought to be the cradle of human origins.

The morphology of the fossil is unusual with a combination of characteristics unlike that found in other early hominids. The braincase is small, estimated at no larger than a modern chimpanzee (preliminary estimate in the range 320-380 cm3), but is massively built -- with huge browridges in front, a crest on top, and large muscle attachments in the rear (see photos). Yet combined with these ape-like features, is a smallish vertical face containing front teeth very unlike apes. In fact, the lower face, being more tucked in under the brain vault (and not protruding as in most other early hominids) is more of a derived feature more commonly expressed in much later hominids (especially members of genus Homo). Moreover, also unlike apes (and some early hominids), the upper canine is reduced and is worn down from the tip (rather than shearing along its side against the first lower premolar). Other dental remains have also been found at the site, represented by two lower jaw fragments and three isolated teeth. Along with the dentition found in the nearly complete cranium, these teeth further indicate a non-ape-like pattern of wear of the canines and only moderate thickness of the molar enamel caps (unlike the more derived thick molar caps found in many later hominids).
East Africa
The Baringo area is part of Africa's Great Rift Valley, which has long been rich in archaeological and paleontological discoveries and the source of almost all fossils related to man's earliest ancestors.

The area is rich in calcium carbonate and calcium phosphate that replace the organic material in bones to form fossils in an environment sealed by lava or volcanic ash.

Kenyan jackpot
Two major discoveries in Kenya added to the debate about the human family tree. In October 2000 the Kenyan Palaeontology Expedition, composed of Kenyan and French scientists, discovered 13 fossil fragments in the rocks of the Tugen hills. These rocks are known to be six million years old, and if the Orrorin tugenensis is recognised by the scientific community, it will become the earliest example of bipedalism yet discovered. At the moment Ardipithicus ramidus, dated to around 4.5 m.y.a. (million years ago), holds this title.
The second discovery, more rapidly accepted by the scientific community, was announced by Meave Leakey of the National Museums of Kenya and her colleagues. Kenyanthropus platyops (the flat faced man of Kenya) was discovered on the western shore of Lake Turkana in northern Kenya. The strata from which the fossil skull has been removed are dated to between 3.5 and 3.2 m.y.a. It is claimed that Kenyanthropus platyops represents a completely new branch of the family tree.

Ethiopian discovery
In February 2001 paleoanthropologists in Ethiopia unearthed a well-preserved partial skeleton (including the all-important skull) of a young hominid from strata dated to 3.4 million years ago. The dig was in the Afar region, south of the famous Hadar site where Lucy was discovered. The age of the hominid puts it roughly half way between Lucy (3.2 m.y.a.) and similar fossils found in Laetoli, Tanzania (3.7 m.y.a).
Nature 410, 433-440 (22 March 2001)New hominin genus from eastern Africa shows diverse middle Pliocene lineages.
New fossils discovered west of Lake Turkana, Kenya, which differ markedly from those of contemporary A. afarensis, indicating that hominin taxonomic diversity extended back, well into the middle Pliocene. A 3.5 Myr-old cranium, showing a unique combination of derived facial and primitive neurocranial features, is assigned to a new genus of hominin. These findings point to an early diet-driven adaptive radiation, provide new insight on the association of hominin craniodental features, and have implications for our understanding of Plio–Pleistocene hominin phylogeny.
South Africa
The first hint that South Africa would become a major player in the search for human origins was the discovery of a hominid skull at Taung in the North West Province in 1924. Fondly called the “Taung Child”, this individual was the first australopithecine to be discovered in the world. That was followed by some spectacular discoveries at Sterkfontein, which is now part of the Cradle of Humankind in 1947. Since then, fossils – mostly also australopithecines – have been turning up at an impressive rate. Australopithecus africanus (literally "southern ape from Africa"). Because of its small size, it was called the "Taung baby." In fact, it was a child of 3-4 years old. Despite its relatively small brain, this species was considered an intermediate between apes and humans. Based mainly on the shape and position of the base of the brain. It indicated that the foramen magnum , or hole in the skull through which the spinal cord passes, pointed downward and was nearly at the central balance point of the skull. This meant that the Taung child must have been bipedal. In addition, the canine teeth were relatively short. In both of these traits, the Taung child was much more like a human than an ape. Most paleoanthropologists in the 1920's rejected claims that Australopithecus africanus was intermediate between apes and humans in favor of the view that it was just an ape. These claims were not widely accepted until the late 1940's.
The undulating landscape containing the fossil hominid sites of South Africa comprises dolomitic limestone ridges with rocky outcrops and valley grasslands, wooded along watercourses and in areas of natural springs. Most sites are in caves or are associated with rocky outcrops or water sources. The serial listing includes the Fossil Hominid Sites of Sterkfontein, Swartkrans, Kromdraai and Environs, and the Makapan Valley and Taung Skull Fossil Site. The Taung Skull, found in a limestone quarry at Dart Pinnacle amongst numerous archaeological and palaeontological sites south-west of the Sterkfontein Valley area, is a specimen of the species Australopithecus Africanus. Fossils found in the many archaeological caves of the Makapan Valley have enabled the identification of several specimens of early hominids, more particularly of Paranthropus, dating back between 4.5 million and 2.5 million years.
The study of decaying organisms over time and how they become fossilized (if they do). The term taphonomy, (from the Greek taphos - meaning burial, and nomos - meaning law describes the study of the transition of remains, parts, or products of organisms, from the biosphere, to the lithosphere, i.e. the creation of fossil assemblages.

Taphonomists study such phenomena as biostratinomy, decomposition, diagenesis, and encrustation and bioerosion by sclerobionts. (Sclerobionts are organisms which dwell on hard substrates such as shells or rocks.)

One motivation behind the study of taphonomy is to better understand biases present in the fossil record. Fossils are ubiquitous in sedimentary rocks, yet paleontologists cannot draw the most accurate conclusions about the lives and ecology of the fossilized organisms without knowing about the processes involved in their fossilization. For example, if a fossil assemblage contains more of one type of fossil than another, one can either infer that that organism was present in greater numbers, or that its remains were more resistant to decomposition.the study of what has happened to an organism from the moment of death until it is found as a fossil. Exploring the process of fossilization from a taphonomic perspective allows placement of individual fossils into a wider context. Consequently, researchers reconstruct not only the morphology of organisms, but under the right conditions, their behavior, life history and palaeoenvironment as well.
Fossilization process
Fossilization is the process that preserves evidence of life in earth's rock record. This evidence of past life is called a fossil. The word "fossil" is derived from the Latin fossilis, something dug up. The use of "fossil" is limited to the record of ancient life. Fossilization can preserve actual remnants of an organism, or evidence of their presence in an ecosystem.

The organism should be rapidly buried to avoid damage by scavengers or weathering agents like water, wind and fluctuations in temperatures.
Fossilization is much more common in marine environments, which are characterized preferentially by sediment deposition rather than erosion.
In continental environments, fossils are most common in fluvial sediments, and rare in soils. The remains require little or no disturbance during the fossilization process.
The organism should be buried in anaerobic conditions, because oxygen encourages the presence of bacteria which decompose organic material. Examples of continental anaerobic environments include wet areas like swamps and floodplains.
Fossil record
the name given to the history of life on Earth as shown by fossils preserved in the rocks.
The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record.
Relative dating
Relative dating sometimes refered to as internal industry, is the science determining the relative order of past events, without necessarily determining their absolute age.
Dating methods
Crucial to the process of understanding the archaeological record. Dating methods encompass both Relative dating and Absolute dating methods, as well as the interpretation of archaeological context and sequence. Many disciplines of archaeological science are concerned with dating evidence.
Incremental dating techniques allow the construction of year-by-year annual chronologies, which can be temporally fixed (i.e., linked to the present day and thus calendar or sidereal time) or floating.
Radiometric dating (often called radioactive dating) is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.
Absolute dating
Absolute dating is the process of determining an approximate computed age in archaeology and geology. Absolute dating (archaeology) is usually based on the physical or chemical properties of the materials of artifacts, buildings, or other items that have been modified by humans. Absolute dates do not necessarily tell us precisely when a particular cultural event happened, but when taken as part of the overall archaeological record they are invaluable in constructing a more specific sequence of events.
Radiocarbon dating
(Absolute Dating)
One of the most widely used and well-known absolute dating techniques is carbon-14 (or radiocarbon) dating, which is used to date organic remains. This is a radiometric technique since it is based on radioactive decay.
Potassium-argon dating
(Absolute Dating)
Other radiometric dating techniques are available for earlier periods. One of the most widely used is potassium-argon dating (K-Ar dating). Potassium-40 is a radioactive isotope of potassium that decays into argon-40. The half-life of potassium-40 is 1.3 billion years, far longer than that of carbon-14, allowing much older samples to be dated. Potassium is common in rocks and minerals, allowing many samples of geochronological or archeological interest to be dated. Argon, a noble gas, is not commonly incorporated into such samples except when produced in situ through radioactive decay. The date measured reveals the last time that the object was heated past the closure temperature at which the trapped argon can escape the lattice. K-Ar dating was used to calibrate the geomagnetic polarity time scale.
Stratigraphy, a branch of geology, studies rock layers and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks.
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. Usually the aim is correlation, demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at some other section. The fossils are useful because sediments of the same age can look completely different because of local variations in the sedimentary environment. For example, one section might have been made up of clays and marls while another has more chalky limestones, but if the fossil species recorded are similar, the two sediments are likely to have been laid down at the same time.
Sexual dimorphism
Sexual dimorphism in non-human primates has long been observed in the primate order, with numerous studies performed to document and explain the phenomenon. Recent studies have mainly used the technique of comparative analysis to examine both the variation in the expression of the dimorphism among primates and the fundamental causes of sexual dimorphism. Primates usually have dimorphism in body mass and canine tooth size along with pelage and skin color. The dimorphism in primates has been attributed to many factors:

Mating system – Polygynous species are more sexually dimorphic than monogamous species, such as the New World monkeys. It is also associated with greater male gonadal investment than what is found in closely related monogamous species.
Size – Larger species are more sexually dimorphic than smaller species.
Habitat – Terrestrial species tend to be more sexually dimorphic than arboreal species. It is possible that male-male competition in terrestrial species is more dependent on body size.
Diet – Frugivores, for reasons that are not clear, are slightly more sexually dimorphic than folivores. Energy may be less of a constraint or maybe females may be more clumped around an area of fruit trees.
Genus: Hylobates
The genus Hylobates is one of the four genera of gibbons. Hylobates remains the most speciose and widespread of gibbon genera, ranging from southern China (Yunnan) to western and central Java.
The Siamang Gibbon (Symphalangus syndactylus) is a tailless, arboreal, black-furred gibbon native to the forests of Malaysia, Thailand, and Sumatra. The largest of the lesser apes, the Siamang can be twice the size of other gibbons, reaching 1 m in height, and weighing up to 14 kg. The Siamang is the only species in the genus Symphalangus.
Genus: Pan
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:

Common Chimpanzee, Pan troglodytes (West and Central Africa)
Bonobo, Pan paniscus (forests of the Democratic Republic of the Congo)
Chimpanzees are the only known members of the Panina subtribe. The two Pan species split only about one million years ago.
Genus: Pongo
The Sumatran Orangutan (Pongo abelii) is one of the two species of orangutans. Found only on the island of Sumatra, in Indonesia.
Genus Pongo:
Bornean Orangutan (Pongo pygmaeus)
Pongo pygmaeus pygmaeus - northwest populations
Pongo pygmaeus morio - east populations
Pongo pygmaeus wurmbii - southwest populations
Sumatran Orangutan (Pongo abelii)
Named for site of Olduvai Gorge in northern Tanzania. Earliest formally recognized cultural tradition of the Lower Paleolithic. Recent finds if accepted suggest that Homo rudolfensis, and perhaps Homo habilis, carrying Oldowan tool technology, spread out of Africa into the Middle East, Asia, and perhaps Europe.
Early and key sites:
Ounda Gona, Ethiopia, 2.6 million years ago (MYA) - core-flake tools and cutmarked bones (equid, bovid); highly selective raw material use
Kada Gona, Ethiopia, 2.52-2.60 MYA - core-flake tools
Bouri, Ethopia, 2.5 MYA - cutmarked animal bones,
Acheulian is the name given to an archaeological industry of stone tool manufacture associated with early humans during the Lower Palaeolithic era across Africa and much of West Asia and Europe. Acheulean tools are typically found with Homo erectus remains. They are first developed out of the more primitive Oldowan technology some 1.8 million years ago, by Homo habilis.

It was the dominant technology for the vast majority of human history starting more than one million years ago.
Major Morphological features of the various hominid taxa
The classification of the great apes has been revised several times in the last few decades. These various revisions have led to a varied use of the word "hominid" – the original meaning of Hominidae referred only to the modern meaning of Hominina, i.e. only humans and their closest relatives. The meaning of the taxon changed gradually, leading to the modern meaning of "hominid", which includes all great apes and humans.Molecular studies suggest that the lineages leading to humans and chimpanzees diverged approximately 6.5–5.5 million years (Myr) ago, in the Late Miocene1, 2, 3. Hominid fossils from this interval, however, are fragmentary and of uncertain phylogenetic status, age, or both.Postcranial skeletal variation among Plio-Pleistocene hominins has implications for taxonomy and locomotor adaptation. Although sample size constraints make interspecific comparisons difficult, postcranial differences between Australopithecus afarensis and Australopithecus africanus have been reported. Additional evidence indicates that the early members of the genus Homo show morphology like recent humans (e.g., Walker and Leakey: The Nariokotome Homo erectus skeleton. hominin footprints in two sedimentary layers dated at 1.51 to 1.53 million years ago (Ma) at Ileret, Kenya, providing the oldest evidence of an essentially modern human–like foot anatomy, with a relatively adducted hallux, medial longitudinal arch, and medial weight transfer before push-off. The size of the Ileret footprints is consistent with stature and body mass estimates for Homo ergaster/erectus, and these prints are also morphologically distinct from the 3.75-million-year-old footprints at Laetoli, Tanzania. The Ileret prints show that by 1.5 Ma, hominins had evolved an essentially modern human foot function and style of bipedal locomotion.

Dental morphology=evolution of diet in the Pan-Homo and hominin clades.thick enamel can protect against the generation and propagation of cracks in the enamel that begin at the enamel-dentine junction and move towards the outer enamel surface.physical properties of food and suggest how these physical properties can be used to investigate the functional morphology of the dentition. We show what aspects of anterior tooth morphology are critical for food preparation (e.g. peeling fruit) prior to its ingestion, which features of the postcanine dentition (e.g. overall and relative size of the crowns) are related to the reduction in the particle size of food, and how information about the macrostructure (e.g. enamel thickness) and microstructure (e.g. extent and location of enamel prism decussation) of the enamel cap might be used to make predictions about the types of foods consumed by extinct hominins.
Nariokotome (WT-15000)
Discovered by Kamoya Kimeu in 1984 at Nariokotome near Lake Turkana in Kenya.
An almost complete skeleton of an 11 or 12 year old boy, the only major omissions being the hands and feet. (Some scientists believe erectus matured faster than modern humans, and that he was really about 9 years old. It is the most complete known specimen of H. erectus, and also one of the oldest, at 1.6 million years. The brain size was 880 cc, and it is estimated that it would have been 910 cc at adulthood (a modern human of comparable size would be expected to have a brain size of about 1350 cc). The boy was 160 cm (5'3") tall, and estimates are that he might have been about 185 cm (6'1") as an adult. Except for the skull, the skeleton is very similar to that of modern boys, although there are a number of small differences. The most striking is that the holes in his vertebrae, through which the spinal cord goes, have only about half the cross-sectional area found in modern humans. One suggested explanation for this is that the boy lacked the fine motor control we have in the thorax to control speech, implying that he wasn't nearly as fluent a speaker as modern humans are.
Catalog number: KNM-WT 15000
Common name: Turkana Boy
Species Homo erectus or Homo ergaster
Age: 1.6 mya
Place discovered Lake Turkana, Kenya
Date discovered: 1984.
Place discovered: Lake Turkana, formerly known as Lake Rudolf, is a lake in the Great Rift Valley in Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake.
Selam (Lucy's baby)
Selam (DIK-1/1) is the fossilized skull and other skeletal remains of a 3-year-old Australopithecus afarensis female whose bones were first found in Dikika, Ethiopia in 2000 and recovered over the following years. She is often nicknamed Lucy's baby. The remains have been dated at 3.3 mya, approximately 120,000 years older than "Lucy" (dated to about 3.18 Ma). The fossils were discovered by Zeresenay Alemseged, and are remarkable for both their age and completeness.
Catalog number: DIK-1/1
Common nam:e Selam
Species: Australopithecus afarensis
Age: 3.3 mya
Place discovered: Dikika, Afar Depression, Ethiopia
Date discovered: 2000
Place discovered: Dikika, Ethiopia, a few miles south (across the Awash River) from Hadar, the place where the fossil remains known as Lucy was found. The recovered skeleton comprises almost the entire skull and torso, and many parts of the limbs. The features of the skeleton suggest adaptation to walking upright (bipedalism) as well as tree-climbing, features that correspond well with the skeletal features of Lucy and other specimens of Australopithecus afarensis from Ethiopia and Tanzania. "Lucy's Baby" has officially been nicknamed "Selam" (meaning "peace").
Classification of Australopithecines
Most anthropologists agree that Australopithecines belong to the same family as modern day humans, Hominidae. From there they are classified into the genus Australopithecus, which means "southern ape", and into four species, afarensis, africanus, boisei and robustus.
Debate about individual role of afarensis, africanus, boisei and robustus in the evolution of the Homo line
There is little agreement, however, on the role that these individuals(afarensis, africanus, boisei and robustus) played in the evolution of the Homo line. Some believe that Australopithecus afarensis was the common ancestor of both the Homo line and the rest of the Australopithecus line. Others believe that this split occurred later on with Australopithecus africanus.Still others argue that these two lines developed side by side by a different common ancestor.In all three cases, both lines were evolved from a common ancestor somewhere in the past that served to separate them from the apes.
Gracile v. Robustus forms of Australopithecines
Australopithecus afarensis and africanus are the gracile forms of this species with rather small and light body structures. Australopithecus robustus and boisei, were more robust individuals with a rather heavy bone structure with big teeth and saggital crest
Catarrhini is one of the two subdivisions of the higher primates (the other being the New World monkeys). It contains the Old World monkeys and the apes, which in turn are further divided into the lesser apes or gibbons and the great apes, consisting of the orangutans, gorillas, chimpanzees, bonobos, and humans. They are all native to Africa and Asia.
The name Catarrhini means drooping nose or downward nosed, and refers to their narrow, downward pointing nostrils, in contrast with the outward pointing nostrils of the New World monkeys (Platyrrhini).

The apes and Old World monkeys split from their New World monkey kin about 35 million years ago. The major catarrhine division occurred about 25 mya, with the gibbons separating from the great apes (including humans) about 15-19 mya.
Debate between Australopithecus and Paranthropus
the Australopithecus genus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct 2 million years ago. During this time period various different forms of australopiths existed, including Australopithecus anamensis, A. afarensis, A. sediba, and A. africanus. There is still some debate amongst academics whether certain African hominid species of this time, such as A. robustus and A. boisei, constitute members of the same genus; if so, they would be considered to be robust australopiths whilst the others would be considered gracile australopiths. However, if these species do indeed constitute their own genus, then they may be given their own name, the Paranthropus.