Ohio University
OU Dept. Biological Sciences
Research
Ultimately, I am interested in the reconstruction of past
ecosystems, primarily but not limited to those of the Mesozoic. However, as I
studied more and more, I found a disheartening tendency for ecosystems to be
reconstructed without adequate understanding of the organisms making them up.
Assumptions were made about roles animals played in the ecosystem without
adequate understanding of how the animals were put together and functioned. There was the added
problem that fossil preservation is a tricky business. Very few animals (or
plants for that matter) become fossils, fewer last through the millennia to
the present day, even fewer are found and collected, and even fewer are
studied in detail. Those that are found and studied are hardly representative
of the ecosystem as a whole. Researchers like to call this, among other
things, preservational bias (generally a polite way of cursing at the
information). It is much like putting together a horrifically complex jigsaw
puzzle without knowing what it looks like, with most of the pieces missing,
and the remaining ones severely damaged.
So, with all this getting in the way, how do we know what we know? My research involves the very first step: how things die and get preserved. How do things become fossils and what can we learn about the animal through a better understanding of the burial process? My previous research during my stint at the University of Colorado at Boulder indicated that the path from bone to fossil was greatly enhanced by interactions with the very bacteria that decompose remains. Fossilization is not an isolated inorganic response to the physical environment, it is an interweaving or ecological interactions.
Extending that line of research, I am looking
at how the physical environment interacts with the carcass during the initial
burial phase. Modern CT machines and software allow us to three dimensionally
map sediment patterns in much greater detail than was possible even a few
years ago. CT scans have revealed differences in the rock encasing the bones
of numerous fossils. However, without any sort of baseline understanding of
how the sediment interacted with the carcass during and after burial, it was
impossible to accurately interpret what these differences might mean. I am attemp
ting to create that baseline information.
Through actualistic taphonomic experiments (in layman's terms, that means I am using present-day materials to study the burial process) to study how varying degrees of decomposition affect the sediment patterns that develop inside and around buried heads. Those patterns may be able to give us more information on the soft tissue that was present during burial even though the original soft tissue is long gone. Mammals, and humans in particular, the regions of the head are well defined by bone. We know exactly where the eyes are located, the size of the nasal cavity and the brain because the bones tell us. But in most other animals, these areas are bounded as much or more by soft tissue that does not preserve as they are by bone. So we have to make educated guesses. Hopefully, understanding how the sediment interacts with the carcasses will allow us to refine those educated guesses. This sort of research is crucial for determining, for instance, whether or not the famous "dinosaur heart" that was discovered is really a heart or just an interesting concretion. As a hint, I will say that my research indicates the chances of the heart being preserved in that manner are astronomically small. Now, one might say the chances of any animal being preserved as a fossil are astronomically small. Fair enough, but take that chance and make it another astronomically small on top of that.
This research may also increase our understanding of what burial conditions are most likely to preserve fossils in exceptional states, those fossils that are fantastically important because they preserve details of the soft tissue that ordinarily decays and vanishes. Field workers would then be better able to target rock formations that may be more likely to contain extraordinary fossils.
If we take a global view of taphonomy, we can also look at overall patterns of evolution. This is not what most people would consider as taphonomy, but to me it is a logical extension and corollary to the idea of practical taphonomic patterns. For instance, paleobiogeography, the mapping of extinct biologic systems (animals, plants, ecotypes, etc.) is dependent on preservation bias. Our understanding of phylogeny is dependent on these biases. But we can potentially use them to our advantage. Take for instance, the common occurrence of multiple published phylogenies for a particualar group. It may be possible to map their global occurrence and compare the patterns with the proposed phylogenetic histories, which may provide more weight to one phylogeny over the other. I do not propose adding these biogeographic characters into the phylogenetic analysis as I do not think that would be appropriate, but if one has multiple competing hypotheses that can not be solved by character analysis, biogeographic information may help. Additionally, it can also point out areas that are likely to hold crucial fossils that may shed light on the phylogenetic conundrum.