Hominid activity

Due Introduction According to Phylogenies, evolutionary relationships between species are derived based on primitive and derivative features. The homo genus, for instance, had larger brains compared to those of the Australopithecines and the living apes: this is an example a derived feature. However, features such as adaptable grasping hands fall under the primitive category, which apes, the australopithecines and modern humans possess (PBS, Riddle of the Bones: What did they look like?). Phylogenies hypothesis generate testable results through scientific methods to determine time chronology of fossil finds (PBS, Riddle of the Bones: When did they live?). So far, scientists are in agreement that human first ancestors were two legged walking creatures with small brains.
Defining species on the basis of extinct fossils can be a tricky affair. Scientific estimations via collected species sample populations are the only way to generate tree diagrams reflective of the human origin. Noteworthy, species exhibits different range of variations. In spite of the extent of accuracy in fossil dating methods, which in fact determines humans’ origin, a number of theories exist with varied explanations on the decent of species leading to the current status of man. Below are sketches of Ian Tattersall, Bernard Wood and Donald Johansson theories of evolution to date.
(Kindly sketch the three Human Family Trees from the website below (just a rough draft-use colored pen)
http://www. becominghuman. org/node/interactive-documentary)
Discussion questions: A tree full of ancestors
According to the three family trees full of ancestors, they all begin with a similar ancestral lineage. Ardipithecus ramidus, who lived approximately 4. 4 million years ago, is at the apex of all the three theories. The hominid, thought to have lived in east Africa, is posited to have been a herbivore surviving on fruits and seeds and leaves. Ardipithecus ramidus evolved years later into Australopithecus Anamensis (4. 2-3. 9 mya). A. afarensis(3. 9-3. 0 mya) immediately followed with almost the same survival characteristics living in almost similar environments in the same region of East Africa-Kenya. The endings are the same. Again, the three evolutionary trees end with similar creatures: the H. Sapiens and H. Neanderthalensis, which are preceded by one immediate ancestor: the H. Heidelbergensis.
Ardipithecus ramidus, which begins evolutionary process in all the three evolutionary theories, is posited to have evolved by its self. If these ancestral theories are to be believed without doubt, then even this hominid must have evolved from something. The second contentious relates to the existence of K. Playtops, which is only in one tree-the Donald Johnson tree. One fact to note is that though Johansson included the hominid in his evolutionary model, the fossils of this creature have never been discovered anywhere. K. Playtops fossils are apparently so out of line with existing phylogenies that scientists find it difficult to position anywhere in the ancestry tree sensibly on their phylogenetic trees. As such, they are often sidelined with numerous question marks for thorough research. Finally, the link between P. Aethiopicus to P. Robustus is still a paradox that requires thorough research: both Ian and Wood argue that Robustus descended from both A. africanus and P. Aethiopicus. However, Johansson deviates from the above view and puts A. africanus as the only ancestor to Robustus. The departure between the two groups occurs on the basis of geographical locality during evolutionary processes and the morphological characteristics of the fossils finds (Strait, Grine and Moniz 49).
Scientific study since its inception has been at the mercy of human endeavor. As such, use of standardized methodology may yield different results due to creativity as well as the intellectual agility built into the processes to achieve the hypnotized objectives. Simply put, any person may achieve contradictory result that might as well be the right answer.
In all the family tree analyzed, every creature either descends or evolves to a new organism with slightly different features. The principal assumption of lineage linkages reigns supreme in all the three evolutionary theories.
It is indeed a fact that as new evidence continues to surface, the branches of evolutionary trees mentioned above may change to accommodate such facts. The discovery of Sahelanthropus tchadensis by Ahounta Djimdoumalbaye south of Sahara in 2001 is already displacing Ardipithecus ramidus as the oldest hominid (Brunet et al. 146). This new fossil finds are dated between 6 and 7 million years old with more primitive ape like features compared to the later hominids. Perhaps, future discoveries will reveal even older ancestral history than those that currently rule the existing evolutionary trees: a clear signal that absolute surety of complete hominid family tree is just but an elusive imagination.
Work Cited
Brunet, M., et al. A new hominid from the Upper Miocene of Chad, central Africa.
Nature, 418. 6894 (2002): 145-151. Print.
Strait, D. S., F. E. Grine and M. A. Moniz. A reappraisal of early hominid phylogeny.
Journal of Human Evolution, 32. 1 (1997): 17-82. Print.
The PBS Library Family of Sites. Evolution: Humans: Riddle of the Bones, 2012. Web.
24 Jul. 2012.