Wednesday, May 17, 2006

Question 1


1. Australopithecus afarensis (Lucy)

Aferensis is an austrapithecus existed between 3.9 and 3.0 million years. It had an apelike face with low forehead. It had a flat nose and no chin. The cranium capacity lies between 375 and 550cc. It was 1.0 to 1.5m in height. However, according to (http//www.bcb 703.blogspot.com)the height of female were substantially smaller than males, height varies between 107cm and 152. It had projecting jaws with moderate size molar. A. afarensis was the common ancestor of both later australopiths and the modern human genus, Homo(http://encarta.msn.com/text_761566394__1/Human_Evolution.html)

2. Australopithecus africanus (Taung child)

It had apelike arms and legs, the arms are longer than arms. It was 1.1-1.4m in height. It was bipedal. The jaw had a parabolic shape. It had no saggital crest and diastema. The brain size was ranging between 420-500cc. It had a small incisor like canine. The bones of the finger and toe are curved heavily built facial and cranial features of A. africanus from Sterkfontein identify it as an ancestor of the robust australopiths that lived later in the same region. http://encarta.msn.com/text_761566394__1/Human_Evolution.html)

3. Australopithecus garhi

This is a species of Australopithecus dated of 2.5 million years ago in East Africa. It had an apelike arms and legs. The cranium capacity was 450ml. It had a premolar like homo genus. It had no diastema.


4. Australopithecus bahrelghazali

The premolar has three roots. Its jaw and teeth are similar to A.afarensis. The teeth were combination of three root teeth typical chimpanzee and other apes. It had a shortened face.

5. Homo habilis

It had flatter face. The skull and skeleton were gracile. The brain shape was more like humans. It was 1.0m in height. The arms were long. The cranium volume was 500-650cc.The jaw was thinner, smaller and narrow molars.

6. Homo rudolfensis

The height of rudolfensis was 1, 5m. It had a mass of 52 kg (114 lb). The cranium volume was ranging from 600-800cc. It had a large and flatter face. The physical structure was robust. It had a robust jaw, large narrow molars. This species had a larger face and body than did H. habilis. A larger brain-to-body-size ratio can indicate increased mental abilities. H. rudolfensis also had fairly large teeth, approaching the size of those in robust australopiths.

7. Homo antecessor

Homo Antecessor was named in 1977 from the fossil found at a Spanish cave of Atapuers. It had a ‘modern face. It had a cranium capacity of 1100ml. It was 1.83m in height and the weight of 19kg. It had an “archaic” back of head very modern. But teeth, forehead and brow ridges were more primitive and chin. It was the common ancestor of Homo neanderthalensis and Homo sapiens.


8. Homo ergaster (Turkana Boy)

It was 1.3 -1.7m in height. The physical structure was robust but “human” skeleton. The brow ridge differ in shape. It had a sloping forehead. It had a large orbital, open nasal and face. It was the complete known specimen of H.erectus. The brain size was 880cc and it was estimated to be 910cc in adulthood. The cranium volume was 750-1250cc.The cranium was also thick. H. ergaster was a good candidate for an ancestor of modern humans because it had several modern skull features, including relatively thin cranial bones (http://encarta.msn.com/text_761566394__1/Human_Evolution.html). It had a robust jaw in large individual. The teeth were small than H.habilis. It was a common ancestor of H.heidelbergensis.

9. Homo erectus (upright Man)

This is an extinct species of primitive hominid that existed between 1.8 -300years. It was 1.3-1.7m in height. The cranium volume was 750-1250cc.Face had a protruding jaws with large molars. It had small teeth like H.habilis. It had a thin brow ridge and no chin. The skull form was flat, thick with large occipital. No chin.

H. erectus had a low and rounded braincase that was elongated from front to back, a prominent brow ridge, and an adult cranial capacity of 800 to 1,250 cu cm (50 to 80 cu in), an average twice that of the australopiths. Its bones, including the cranium, were thicker than those of earlier species. Prominent muscle markings and thick, reinforced areas on the bones of H. erectus indicate that its body could withstand powerful movements and stresses. Although it had much smaller teeth than did the australopiths, it had a heavy and strong jaw (http://encarta.msn.com/text_761566394__1/Human_Evolution.html).


10. Homo heidelsibergensis

It was 1.5m in height. The cranium volume was 1100-1400cc. The physical structure was robust but human skeleton. It had a higher skull and faces less protruding. It had jaws which are similar to H erectus, but teeth were smaller. It was descended from H.erectus and a common ancestor of both modern and H.neanderthalensis.

11. Homo rhodesiensis

It had a brain size of 1280cc. The muscles are strong. The association of the bones is unclear. The tibia and femur fossil were associated with the skull. It had a cranium capacity of 1,300cc. The skull had a broad face with large nose and thick protruding.

12. Homo neanderthalensis

The average height was 1.5-1.7m.The cranium volume was 1200-1750cc. The brain size was slightly large than that of human being. Neanderthals were adapted to the cold, as shown by their large braincases, short but robust builds, and large noses. On average, Neanderthal males stood about 1.65m tall (just under 5' 6") and were heavily built, and muscular due to their physical activity. Females were about 1.53 to 1.57m tall (http://en.wikipedia.org/wiki/Neanderthal_Man).

It had a protruding jaw and receding forehead, double arch brow ridge, weak chin, large nose, long incisors, thick bones that indicate that the powerful muscle were attached ,feature that is not found in H.erectus and adaptation to cold, a large, long, low cranial vault with a well-developed double-arched brow ridge, a massive facial skeleton with a very projecting mid-face, backward sloping cheeks, and large nasal aperture, with large nasal sinuses, an oddly shaped occipital region of the skull with a bulge or bun, molars with enlarged pulp chambers, and large, often very heavily worn incisors, a mandible lacking a chin and possessing a large gap behind the last molar, a massive thorax, and relatively short forearms and lower legs, although short in stature they possessed robustly built skeletons with thick walled limb bones, long clavicles and very wide scapulas (http://www.actionbioscience.org/evolution/johanson.html)

13. Homo sapiens idatlu (elder wise man)

This species are likely to present the direct ancestor of modern Homo sapiens sapiens. The average brain size was about 1350cc. The brain capacity was 1450cc. The skull had deep face which was long. It used stone tools to slaughter large animals

14. Homo sapiens sapiens (Wiseman’modern human)

This is the last stage of evolution in our genus. The skull size and shape are completely modern. The forehead rises sharply, eyebrow ridge are very small or absent, the chin is prominent and the skeleton is gracile. The body is less robust. The average brain size is 1350cc. Modern human have large mastoid process and small chest cavity. The pre molar have three roots. It jaw and teeth are similar to A. afarensis. The modern human line descended from H. ergaster.

Homo floresiensis

This species descended from the upright ancestor (H. erectus).The mass of H. floresiensies was 25kg (551b). It had long arm that help the hominid to climb safely in the trees. The brain capacity was 380cm3. The skeleton was robust.

Question 2

The Piltdown is one of the famous in history of science. The skulls were discovered by Charles Dawson in Piltdown quarry. The skulls were fragment and very curious jawbone. The skull displayed characteristics of both man and ape. The jaw was ape-like whereas the upper skull fragments were definitely human. (http://www.talkorigins.org/faqs/piltdown.html)

The Piltdown man was accepted by the scientific community for many years. However, the different research the piltman was found that was unlike anything else in the fake. The fluoride based test was used to determine the upper skull. The results indicated that the upper skull was approximately 50,000 years old. The skulls were unusually thick and the jaw bone was a few decade. They also found that the jaw had been artificially stained with potassium dichromate to make it appear older.

The bones were gathered from the variety of sources. They also had a treatment in order for them to appear genuinely. The bones were treated with chromic acid to convert the bone appetite to facilitate the intake of the iron and manganese. The skull may also been boiled in an iron solution. The canine tooth was painted after staining, probably with Van Dike brown. It was also filled to show wear and it was filled with sand as it might have been if it had in the Ouse River. The jaw bone molar was filled to fit. However, the biting surface of the two molars did not form uniform surface, the plane were out of the alignment. The connection were the jaw bone met the of the skull was carefully broken so that there would no evidence of lack of fit (http://home.tlac.net/~cri-a/piltdown.html#dawson)

Dawson, Pierre Teilhard de Chardin, and Woodward were the possible persons involved with perpetuating hoax. . Dawson was guilty because he made the first two skulls. In 1915 Dawson discovered two pieces of a second skull, together with a molar tooth in, remarkably, a ploughed field, not a quarry, five kilometers away. These became known as Piltdown II. He alone was a culprit, he had both necessary knowledge and the requisite character and his participation was necessary. He did not arrange that the skull fragment to be tested. (http://www.museumofhoaxes.com/piltdown.html).



Pierre Teilhard participated in the dig. He was with Dawson when he found the famous jaw bone, and was the one who found the all-important canine tooth. He had studied in the Middle East and could have imported the improbable mammalian bones He was with Dawson when he found the famous jaw bone, and was the one who found the all-important canine tooth. He had studied in the Middle East and could have imported the improbable mammalian bones (http://www.abc.net.au/rn/science/ockham/stories/s987276.htm).


Woodward was contacted by Dawson about the two skulls. Woodward displays a reconstruction of the skull at the meeting of the Geological Society. He argues that it was the skull of a man. He also argue that it come from human who lived about a millions years ago. He won the argument and a result the new species entered the text book as Eoanthropus dawson or “Dawson Dawn Man”. Whoever perpetrated the crime, it is considered to be one of the damaging scientific hoaxes (http://www.takorigins .orgfags/piltmandown.html).

Question 3

Taung child refers to the fossil of the skull specimen of Australopithecus africanus. The species was discovered by Dart in 1924. It had a prognathus face with no eyebrow ridges. The appearance of the species did not convince the popular status of its status as an ancestor. The skull of the Taung child displayed both ape-like and human anatomical feature. It had apelike arms and legs, the arms are longer than arms.

Dart recognized distinctly human features in the fossil and proposed the classification of a new genus and species Australopithecus africanus -- "Man/Ape of southern Africa". These features included a flatter, less projecting face than in apes, a rounded head with a lack of brow ridges, and a lightly built mandible that did not have a diastema (a space between the lower canine teeth and the first premolars), which is seen in apes. The natural endocast gave a cranial capacity of 405cc with a projected adult measurement of 440cc, somewhat larger than in modern (http://www.mnh.si.edu/anthro/humanorigins/ha/taung1.html).

Many researchers for examples the brain specialist Dean Falk criticized Dart about his analysis of the skulls. Darts did not fully appreciate infant apes have not had time to develop features of the skull. Such as thickened eyebrow ridges or attachment areas for heavy neck muscle. That set adult apart from human. He did not clearly consider that that Taung’s rounded forehead are inferred position of the spinal cord might be due to the immaturity of the apelike specimen rather than to its resemblance.

Sir Arthur Keith, anatomist and prominent supporter of Piltdown, argued that this was an immature chimpanzee. However, there was one additional feature to the Taung Child that was not easily explained away as a characteristic of an immature ape. The position of the foramen magnum, or the hole through which the spinal chord connects with the brain, was positioned well to the front of the skull, an adaptation of a bipedal creature whose head would rest a top the neck in a relatively balanced position (http://www.mnh.si.edu/anthro/humanorigins/ha/taung1.html).

Conversely, a quadruped ape whose head would rest in front of the neck would need a foramen magnum positioned to the rear of the head to keep its eyes facing forward, and not down, as it moved. If this truly was a chimpanzee, and not an early human, why the forward positioning of the foramen magnum? (http://www.mnh.si.edu/anthro/humanorigins/ha/taung1.html)

Dart's publication on the "Taung Child," as it was being called, met with immediate criticism from an established community for the most part committed to Piltdown Man. Much of the criticism centered on the fact that this was the fossil of a child. Many of the features listed above are known in modern apes prior to maturity, and the fact that the first molars of the Taung Child had only just started to erupt indicated that the individual was a juvenile (http://www.mnh.si.edu/anthro/humanorigins/ha/taung1.html).

Question 4

Figure. 1. Representation of an evolutionary relationship between humans,Chimpanzees, Gorillas, and Gibbons in million years ago.

According to their research, the chimpanzees are the closest relatives of humans; the next in line are the gorillas. The orangutans are only remotely related to the other species. Differences are especially small in the nuclear DNA. Certain genes that were analyzed differ by only 1.2% between humans and chimpanzees, by 1.6% between humans and gorillas and by 1.8% between gorillas and chimpanzees. In contrast, analyzed parts of the genetic material of humans differ from the respective genetic material of the orangutan by about 3.1%. In mitochondrial DNA, which changes considerably faster, geneticists found a difference in 8.8% between humans and chimpanzees, 10.3% between humans and gorillas, and 10.6% between chimpanzees and gorillas and 16-17% difference between the other species and the orangutan. (http://encarta.msn.com/encyclopedia_761566394/Human_Evolution.html)
The evidence linking human to gorilla and chimpanzees was grown dramatically in the past decade, especially with increased molecular techniques. Chimpanzees, gorillas and human form a clade of closely related species. Orangutans are less phylogetically and gibbons are more distant branch. However, they all make up the family of Hominade except gibbons.

The common ancestor and pygmy Chimpanzees differ about 0.7% of their DNA and diverged about 3mya. Chimpanzees Human differ with 1.6% with both species diverged from common ancestor of about 7my. Gorilla differ in approximately 2, 3% of DNA from human. Human differ from both common Chimpanzees and pygmy Chimpanzees in about 1, 6% of the DNA and share 98.4%. The gorillas must have branched off from human family three slightly before separation. The Chimpanzees are closest relating, the genetic distance 1, 6% separating pygmy is double human. Distance separating pygmy from common ancestor is 0.7% and is less than that found between species of Gibbons (2.2%)

Gibbons are smallest of the ape family. The arms of gibbons are relatively longer than their legs. They are covered with light coloured to very dark brown dense hair. Chimpanzees are long and short. Their bodies are mostly covered by with black hair. They have large ears, an elongated snout, small nostrils and slightly brow ridge.

The structures of the Gorillas have robust build with long muscular arms and short legs, a massive chest, and broad hand and feet with thick digits. They knuckle-walk using their both arms and legs. The head of the gorillas are large with a bulging forehead. Most of the bodies of Gorillas are covered by brownish hair. Hairs are used to insulate from cold of living high elevation. They have a tiny ear, small dark brown eyes.

Orangutans have large bulky body, very strong arms, thick neck, large head with a prominent mouth area, are about ⅔ the size of the gorillas. They are mostly covered with a long reddish brown hair.

Question 5

African Eve is an ancestor who had been hypothesized on the ground as well as DNA evidence. She is a woman who lived 200.000years ago. The African Eve theory is based on the hypothesis that Homo sapiens sapiens appears in Africa over million years ago and migrated into Europe and Asia. It is sometimes called Mitochondrion Eve because Mitochondrion DNA (MtDNA) was studied in the research of finding the origin of human evolution. (MtDNA). The MtDNA study of African Eve deals with mutations in the DNA nucleotides. The entire human descended to from an “African Eve.

It assumes that the only MtDNA is transmitted from off-spring through the egg cytoplasm. This is also confirmed by the molecular biologists the late Allan Wilson and his associates at U.C Berkely; the mitochondrion is not inherited from the male but is only inherited from female (www.wikepedia org/wiki/mitochondrion-Eve).

The Genetic, Anatomical and Archaeological evidences were used to find the origin of human, In support of an African origin for Homo sapiens the work of Cann and Wilson has demonstrated that the highest level of genetic variation in mtDNA occurs in African populations. This implies that Homo sapiens arose first in Africa and has therefore had a longer period of time to accumulate genetic diversity. Using the genetic distance between African populations and others as a measure of time, they furthermore suggested that Homo sapiens arose between 100,000 and 400,000 years ago in Africa.

Analysis of mtDNA by Rogers and Harpending supports the view that a small population of Homo sapiens, numbering perhaps only 10,000 to 50,000 people, left Africa somewhere between 50,000 and 100,000 years ago (http://www.actionbioscience.org/evolution/johanson.html)

The anatomical and paleogeographic evidence suggests that Neanderthals and early modern humans had been isolated from one another and were evolving separately into two distinct species.
Archaeological evidence from Europe suggests that Neanderthals may have survived in the Iberian Peninsula until perhaps as recently as 30,000 to 35,000 years ago. Fully modern humans first appear in Europe at around 35,000-40,000 years ago, bringing with them an Upper Paleolithic tool tradition referred to as the Aurignacian. Hence, Neanderthals and fully modern humans may have overlapped for as much as 10,000 years in Europe. Again, with fully modern humans on the scene, it is not necessary to have Neanderthals evolve into modern humans, further bolstering the view that humans replaced Neanderthals (http://www.actionbioscience.org/evolution/johanson.html).

The appearance of fully modern behavior apparently occurred in Africa earlier than anywhere else in the Old World, but spread very quickly, due to population movements into other geographical regions. The Upper Paleolithic lifestyle, as it was called, was based essentially on hunting and gathering. So successful was this cultural adaptation that until roughly 11,000 years ago, hominids worldwide were subsisting essentially as hunter-gatherers (http://www.actionbioscience.org/evolution/johanson.html).

Archeological evidence is generally considered to support the initial spread of humans within Africa from an East African origin during the first half of the last 100 000 years and the spread from the same origin to all the world in the last 50-60 000 years (50-60 kya).
The theory was criticized by Ryan; the basic biology behind the "African Eve" theory is as follows. While most of our genes are coded for in the DNA of the cell nucleus, some are in the cytoplasm, associated with mitochondria, the site of much of the cell's energy metabolism. Mitochondrial genes lack the introns and long expanses of functionless DNA found in the nucleus, and mitochondrial DNA (mtDNA) evolve quickly. Such DNA lacks repair enzymes which correct mutations, so that genetic changes accumulate at around 10 times the rate of nuclear DNA.The standard "African Eve" theory holds that mtDNA is maternally inherited because sperm provide no mitochondria to the fertilized egg. This is an absolutely crucial assumption of the theory and if it is false (which it is) the theory immediately collapses. (http://www.alor.org/New Times%20survey/critique%20African20% Eve% 20Theory htm)

Conclusion

For the moment, the majority of anatomical, archaeological and genetic evidence gives credence to the view that fully modern humans are a relatively recent evolutionary phenomenon. The current best explanation for the beginning of modern humans is the Out of Africa Model that postulates a single, African origin for Homo sapiens. The major neurological and cultural innovations that characterized the appearance of fully modern humans has proven to be remarkably successful, culminating in our dominance of the planet at the expense of all earlier hominid populations (http://www.actionbioscience.org/evolution/ingman.html)

Molecular biologists studying certain genetic components of today's humans had come to the startlingly precise conclusion that all family trees lead back to a single African woman who lived some 200,000 years ago -- the mother of all humankind, who inevitably came to be known as Eve (http://query.nytimes.com/gst/fullpage.html)

Question 6

6.1 Stone Age Softies

It is believe that early men were hunters of animals but some discoveries indicate that they were not hunters. They were hunted by the predators. It is believed that early men used to fight with each other but now it is said that because the predators, men came together in order to protect each other from enemy. It was believed that since men were hunters, it meant that they ate a lot of meat however, some new discoveries came out after some research conducted by Robert Sussmen that the early men only had small teeth which is a clear indication that they were unable to eat meat. Sussman said that the fossils evidence pointed that early human were being hunted without explaining how the evidence were found

Early men would live on the tress and on the ground this however, also suggests that man looked like animals which are now hunted for meat. It is also suggested that early man were animals that used their brain to run away from the predators that made them to come together. This helped them to care for each other which are contrary to what was believed that early men fought each other. This article is more accurate .The method of isotopes was used to analyzed the fossilized teeth of Australopithecus Africanus clearly explained. It is able to eat meat of small mammals

6.2 A taste for meat

The article is talking about the species which is Australopithecus afarensis. Matt Sponheimer fossil evidence is clearly explained.

6.3 Table shows the differences between two articles.

BBC STONE AGE
Men ate meat long time ago Men did not eat meat but plants
Austroopithecus africanus lived about 3 million years ago and ate modern chimpanzees. Australopithecus afaransis lived about 2-5Millon years and eat trees and nuts gathered from trees.
Later hominids looked food in open environment and ate meat of animals they killed with stone tools. They were not hunters but they were the predators hunted by the predators.

Their teeth suggest that they ate diverse diet which includes meat. Their small teeth suggest that they were unable to consume meat.The started eating meat some millions years ago. They only started eating meat after using sharp tools some millions of years later.
Developed their large brain after they began eating nutrient and energy rich animal Developed their intelligence after attempts to outsmarts the predator
Dietary quality improved through the consumption of food Predation was a major pressure on our evolution

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