Summary and Reflection

Today I will be overviewing the position of Ardi and the entire Ardipithecus species with regards to the larger picture of human evolution. I will also be going over any question I have regarding Ardipitheucs ramidus and how research could answer some of those questions.

            Ardipithecus ramidus is an early hominin, meaning that it lived before the Australopithecines that led to modern humans. The main question that needed answering is whether or not Ardi has a direct link to human evolution, or because it has similarities to modern apes, if it led to their lineage. A study titled “Ardipithecus ramidus and the evolution of the human cranial base” looked at the basicranium of Ardipithicus ramidus and compared it to modern humans, apes, and Australopithecines. The results of the study demonstrated that Adripithecus ramidus is a human ancestor because its bacarotid breadth, 45.6%, is close to the modern human sample of ~49% and Australopithecine sample of 43.6%. The Ardipithecus sample does not overlap with the ape sample of 35-39%. This similarity, along with others makes it clear that Ardi is likely ancestral to Australopithecines.

This chart shows the results of the cranial base study

            I believe that Ardipithecus ramidus is a good species because it is very distinct from any other fossil. The anatomy of Ardi is so unique that it has its own genus, shred only with the slightly different Ardipithecus kadabba. The actual fossil in question, ARA-VP-6/500 is undoubtedly Ardipitheucs ramidus as it is one of the most compete skeletons attributed to the species and displays all of the morphological characteristics that define the ramidus species.

Many of the questions I have concerning Ardi have to do with not having enough individuals to study or the technology needed to study the fossil in ways that would answer important questions. Firstly I would like to know more specifically how Ardipithecus ramidus fits into the human lineage, and what tis direct descendent species was. More fossils would likely have to be found in order to answer this question. I also want to know what Ardipithecus ramidus evolved from. At the moment there is not definite known lineage before Ardi, which I hope will one day be known. If modern science could obtain DNA from older fossils I think we would find some very interesting and more concrete answers. Unfortunately it will likely be a long time before DNA can be extracted from older fossils, and Ardi’s DNA is most likely degraded due to time.

With every discovery in paleoanthropology many more questions are asked that cannot be answered because it is a guessing game. There is no way to know for sure if answers are true which can be frustrating. There are also usually only a handful of fossils with which scientists are asked to infer an entire species behavior from. As this is the last post on this topic I hope I have been able to provide sufficient information on how Ardipithecus ramidus lived despite the uncertainty of those answers.

An artist's representation of Ardipithecus ramidus that I think highlights it's humanity.

Bibliography:

Kimbel WH, Suwa G, Asfaw B, Rak Y, White TD. 2014. Ardipithecus ramidus and the evolution of the human cranial base. Proceedings of the National Academy of Sciences [Internet] 111:948–953. Available from: http://www.pnas.org/content/111/3/948.full 

Second Image source:

http://www.age-of-the-sage.org/evolution/ardi_human_origins.jpg