The human ancestral line has long been established to be a diversification of the apes (biology-online. org). The said conclusion was based on the genetic study of the human specie and those of the other animals being compared. Classified under the family of hominidae, only the human specie, called the “homo sapiens” were said to have survived.
The others-Homo habilis, Homo-erectus and the Australopithecus were disclosed by science to have been extinct (Britannica, 1997).Pongidae, of which anthropoid apes belong (gorilla, chimpanzee and orangutan) was said to have no contribution or link to the human evolution when vital features such as speech, bipedalism and the brain were compared (New Scientist, 2007). There is one important study was done on ape gestures that gave scientist a clue to the evolution of human communication. The distinctive features of apes and humans, facial expressions and vocalizations were also present in the group of studied chimps.
Where the difference lies is on the frequency of response, a factor of which the studied bonobos responded more often. The researchers therefore conclude that “bonobo is a better model of symbolic communication in our early ancestors” (A. Pollick) As the world progresses, the instruments used to determine and calculate the time backwards, the previous findings on human evolution by merely using fossil comparison and predating were beginning to lose its integrity. With the use of DNA studies, science was able to find some valuable links on human evolution.By comparison, the DNA of chimps and humans differ only by 1.
2% which changes at a regular rate (S. Begley). Molecular clock findings of chimps and human DNA also suggest that the lineages of the two creatures split in about five to six million years ago. The apes were split into two worlds when the earth became extremely cold. According to the DNA study, the apes which stayed in the forest did not evolved as humans and were said to be the ancestors of today’s chimps. The other group, which survived in the grasslands, was the apes which evolved into the human specie.
Still, this finding points to apes as our ancestors. When Lucy was discovered in Ethiopia in 1974, the evidence of our ape ancestry was confirmed. Lucy’s skeleton was dated 3 million years old and said to belong to the genus australopithecine which were believed to be the first evolutionary line of early hominids to move out of the jungle. By studying the features of Lucy, the researchers confirmed that she belongs to the specie of Australopithecus afarensis which have the closest features similar to man (bipedalism and the structure of the head).
Also, a separate DNA study result published by the University of Cambridge in the Science Daily, confirms the “Out Of Africa” hypothesis that all modern humans stem from a single group of Homo sapiens (Science Daily, May 10, 2007). Mitochondrial DNA of Aboriginal population of Australia and the Y chromosomes of Melanesians of New Guinea were analyzed by the researchers and found out that they share the same genetic features. The researchers therefore concluded that Homo Sapiens had actually replaced the other early human species like the Neanderthals as opposed to the hypothesis of interbreeding.B) Human evolutionary history is more like a multi-branched bush rather that an un-branched ladder, our species being the tip of one human branch that still exists.
If we are to consider recent fossil discoveries and DNA analysis, we can say that the human evolutionary history is more like a multi-branched bush rather than an un-branched ladder. A latter confirmation of the validity of the “out of Africa” hypothesis through the DNA analysis made by the University of Cambridge will tells us that homo sapiens evolution is more like a ladder.However, the discovery Lucy and Selam, fossils which were said to be classified as Australopithecus afarensis made things complicated. Studies on Lucy revealed features that are closely similar with the modern humans as well as with that of apes rendering Lucy a half-ape and a half-human. Selam’s discovery in 2000 also revealed almost the same features which suggest that Selam can be modern human’s model of early childhood (M. Henderson). In 2004, LB1 was discovered in Flores, Indonesia by the group led by Peter Brown.LB1 was classified as Homo Florensis because of its shared features with both Homo Erectus and Homo Sapiens (E.
R Wayman). Her discovery is another point considered by scientists that needs thorough study on its relationship with the human evolutionary link. We cannot really say that scientists were already with their quest for clearer answers as discoveries come time after time, all revealing new ideas on human evolution.
If all of these new discoveries are to consider in the human evolutionary links, we can say that it is really a multi-branched bush.C) During the course of hominin history many species of humans (Genus Homo) existed, but not at the same time. Of the genus Homo, science said that there were then three that exist in the hominin history: the Homo erectus, the Homo habilis, and our specie the Homo sapiens although there was later discovery of the genus Australopithecus which was also linked to the evolutionary line of human ancestry. The existence of these genres was widely accepted but debates arose as to the exact time of their existence. There were also concerns on whether which one is the ancestor of which or if they lived all at the same time.If we are to base conclusions on fossils and ancient tool discoveries associated with the hominin history, it is likely that we will draw a conclusion that the three species lived at the same time. The argument of other experts is that the differences on tools and skeletons found in Africa and Australia are suggestive of interbreeding. However, dating the fossils will reveal the opposite result.
Homo Habilis fossils were dated to about 2 million years old which were considered to be the earliest toolmaker, having brains bigger than that of the chimps.Homo Erectus were believed to have lived about 1. 6 million years ago, were the hominids who left Africa and moved to temperate zones. They are the ones who mastered fire and produced well-made tools and whose fossils were found in Java, China and Europe. They are the ones called Peking Man and Java Man. By physiological comparison, scientists are convinced that habilis and erectus lived on different environments but scientist suggest that erectus was the direct descendant of the habilis who moved out of Africa.DNA analysis also suggests that the Y chromosome of the erectus were passed intact from generation but undergone some mutations. An experiment made by Peter Underhill of Stanford University on 1,062 men across the world revealed that human ancestors left Africa 89,000 years ago in Africa and just left 66,000 years ago.
Because erectus left Africa a million years ago, they cannot be human beings direct descendants. By dating African migration, we can say that the three genus did not live at the same time. D) Ancient hominins hunted dinosaurs as a food sourceThis is only one of the misconceptions on human evolution. Science for so long made us believe that it was the predatory ability of our ancestors which allowed them to survive.
Recent studies revealed that humans were more of being a prey than predators. Evidences of produced by the discovery of Lucy (A. afarensis) suggest that they are vegetarians because of their small teeth that was good only for nuts and fruits and not meat (S. Begley). Also, their kinds stood only three to five feet tall, weighing 60 to 100 pounds.Having the knowledge of how huge and mighty meat-eaters dinosaurs were, hominins cannot, by logical reasoning, hunt dinosaurs for food. E) Our understanding of human ancestry and evolution is complete By simply tracing the list of discoveries relative to human evolution, we can immediately conclude that our understanding of human ancestry and evolution is not yet complete.
As had one anthropologist once commented, “We still have a great deal to learn about our evolutionary past, and more surprises may well lie ahead” (E. R.Wayman). New discoveries come every now and then and after each make changes on our previous understanding of human ancestors. First, human beings came from the genus Homo and our specie, Homo Sapiens was believed to be the only surviving ones. Then, Lucy was discovered in 1974, which was classified as Australopithecus afarensis having apelike features but also had features similar with that of the modern man (S. Begley). Then in December 2000, Selam’s fossils were unearthed four kilometers from the area where Lucy was discovered.
Selam places earlier claims connecting apes and humans into confusion because of its features that were similar to both apes and humans. Classified as A. Afarensis, Selam was a biped but also has features that say it climbs trees like that of apes. Its brain case resembles more of an ape but its brain suggest that it places a starting point of the human intelligence’ evolution. Selam’s tongue bone is more similar with that of the modern apes than human which suggest that Selam is incapable of speaking. If so, A.
afarensis cannot be our ancestor.There two things here: either Selam do not belong to A. afarensis specie or A. afarensis do not belong to the lineage of modern humans. In 2001, Toumai’s fossils were discovered in Chad claimed to have been the oldest fossil of our human ancestor. Toumai was classified as Sahelanthropus tchadensis, which was said to have lived after the split of two lineages.
Then in 2005, fossils can no longer stand alone as evidences that confidently tell us where human beings really came from. DNA studies changed our previous belief that humans survived the test of times because of their predatory abilities.Robert Sussman of Washington University concluded that humans then were more of being preys than predators. The genetic study lead by Matthew Rockman of Duke University said that there was a high rate of change in the genes of humans from the time out lineage split from chimps making it the human’s evolutionary advantage. Studies are not yet over. More and more efforts are being made to discover more fossils and archeological evidences, studies on genetics and the human brain structure which should make everybody anticipate on new information about human evolution.
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