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
