ANT 3514C – Introduction to Biological Anthropology
Lab 10: Evolution of the Genus
Critically evaluate the morphology of the taxon
Describe major anatomical changes from Early
and other derived
species of genus
Appraise the arguments for lumping and for splitting fossil hominin specimens into various
taxa and formulate an informed opinion.
Interpret the mosaic of features seen in recently discovered species of the Genus
To illustrate cranial and postcranial anatomical distinctions of the genus
more primitive bipedal hominins.
Recall our very first lab and how challenging it was to arrange the imaginary Caminalcules into a
satisfactory taxonomy that everyone agreed on. Now envision that all you have to create your
taxonomy are a few, incomplete fossilized remains that represent only a fraction of the total
original diversity of taxa and whose behavior and ecology can only be inferred, not directly
observed. This is the problem paleoanthropologists face every time they discover a new fossil. As
you can imagine, there is much disagreement over how to correctly classify our hominin relatives,
and arguments intensify when a researcher claims that a fossil species is particularly closely
related to modern humans.
One of the many challenges paleoanthropologists face is that it is difficult to define what a species
actually is. According to the
biological species concept (BSC)
, a species is a group of
organisms that are potentially or actually able to interbreed. This definition might seem
straightforward, but it is not; in nature there are many circumstances where the BSC is difficult to
apply or observe. For instance, sometimes organisms that are clearly different morphologically
can interbreed and produce fertile offspring. Alternatively, some organisms that appear
indistinguishable to us might be unable to interbreed due to differences in the timing or behavior
of reproduction. Researchers have therefore come up with many other definitions of species.
Unfortunately each definition can be problematic and none of them work perfectly in all instances.
Defining species becomes even more challenging with extinct taxa, when we are left with only
fossils and no way to directly observe soft tissue or behavior.
Consequently, the argument about whether hominin fossils should be “split” into distinct species
or “lumped” into one diverse species is particularly common in paleoanthropology. This is typically
referred to as the
“lumper vs. splitter” debate
. A hominin taxon that makes a good example for
the lumper vs. splitter debate is
. In this week’s lab, we will consider the validity
as a distinct taxon, yet your textbook makes no mention of this species. This is
because many researchers, including the authors of your textbook, lump