In this blog post I will be
addressing the time period when Ardi lived as well as its habitat. Knowing the
age of the fossil is extremely useful in figuring out how Ardi relates to the
rest of the hominins and to modern humans. Knowing the environment in which it
lived is very important in discovering its locomotion and how it lived in its
society.
Most scientists today agree that Ardipithecus ramidus is
dated to have lived around 4.4 million years ago, however that was not always
the case. Dr. John Kappelman and Dr. John G. Fleagle had an issue with the
initial date published, 4.387± 0.031mya. Their argument said that because this date
was only taken from stratigraphic markers and was assumed to be the maximum age
of the Ardi fossil, there is not enough data to make this assumption. They said
that Ardipithecus ramidus should be dated at between 3.89 and 4.39 million
years ago. However, further research with argon dating and paleomagnetic data
prove that the fossil is dated 4.388±0.053mya, which is very similar to the
initial date of 4.387±0.031mya. In my opinion it is better to be challenged and
do more research to clarify the date of a fossil than to assume to date based
on one piece of evidence (Kappelman).
Past and present.
Ardipithecus's woodland was more like Kenya's
Kibwezi Forest (left) than Aramis today (Gibbons).
Ardipithecus ramidus was found in Aramis, Ethiopia,
which today is a dry grassland with a few sparse trees. However, the landscape
was very different in when Ardi lived there. Research based on fossil bones of
other animals found near the Ardipithecus ramidus site showed an abundance of
birds as small mammals living around Ardi. The 29 species of birds include
parrots and peafowl (Louchart). The presence of peafowl is important because
modern peafowl live in open forests and indicates that Ardipithecus ramidus
“was close to or in [a] forest, with watercourses” (Pickford). Another study
used carbon-isotope techniques of the teeth of five individuals, which showed
that “Ar. ramidus ate mostly
woodland, rather than grassland, plants” (Gibbons). All of this evidence
combines into a picture of Ardi living in a forest instead of a savannah or
grassland.
An artist reconstruction
of what Ardipithecus ramidus may have looked like in its natural habitat
(Matternes).
Before scientists looked
at the area around Ardipithecus ramidus and actually studied the fossils, they
assumed that bipedalism evolved in a grassland. I think that it was very presumptuous
of scientists to think that without any evidence. I am glad that with the discovery
of Ardi has come a new, better, understanding of the environment in which
humans evolved.
Gibbons A. 2009. Habitat
for Humanity. Science [Internet] 326:40. Available from: http://science.sciencemag.org/content/326/5949/40.full
Kappelman J, Fleagle JG.
1995. Age of early hominids. Nature [Internet] 376:558–559. Available from: http://search.proquest.com/docview/204469195?accountid=11667
Louchart A, Wesselman H,
Blumenschine RJ, Hlusko LJ, Njau JK, Black MT, Asnake M, White TD. 2009.
Taphonomic, Avian, and Small-Vertebrate Indicators of Ardipithecus ramidus
Habitat. Science [Internet] 326:66. Available from: http://www.jstor.org/stable/40328574
Matternes J. 2009.
Standing Tall. Society for Science & the Public. Available from: https://www.sciencenews.org/article/evolutions-bad-girl
Pickford M, Senut B,
Mourer-Chauviré C. 2004. Early Pliocene Tragulidae and peafowls in the Rift
Valley, Kenya: evidence for rainforest in East Africa. Comptes Rendus Palevol
3:179–189.
