domingo, maio 17, 2009

Entrevista a Phil Mannion, PhD Student

RA: How can we assess diversity from 65M.y old creatures?

PM: We can do simple things like counting the number of genera or species through time. This gives us a rough idea of fluctuations in diversity. However, this can be affected by various processes in the geological record, so, we need to consider where the amount of terrestrial rock varies through time, for instance. Maybe if we have an increase of rock exposure and an increase in diversity, so that increase cannot be genuine. So we can plot diversity against rock record and various proxies like that. We can also correct phylogenies. We know phylogenies are hypothesis of relationships, so we can use those lineages against time and we get another view and explore taxic diversity.

RA: OK, but that has an underlying assumption which is valid. How can this affect your work?

PM: Yes, a phylogeny is only a hypothesis and there is space for mistake in there. We hope that most of the space is small, so it won’t make much difference. Perhaps if a group is in a completely wrong place we will get very long ghost-lineages and the reason why we haven’t look at any taxon there is not because there is a ghost-lineage, but that we just got things wrong. However if you do things like phylogenetic diversity estimate and you do it to various proxies, such as the rock record, than hopefully you can compare them all and you start seeing certain points where you get the same results again and again.

RA: What are the next steps on your research?

PM: The real next step is to finish my thesis! [laughs] I should finish it in the next four to five months.

RA: No… but I mean in scientific terms?...

PM: Well, yeah… Carry on the diversity work. Trying to resolve where the taxic diversity is genuine or logically predicted from the fluctuations of the rock record. And that is sort of near an end. But I also want to go on broader macroevolutionary questions, look at what happened at the K-T boundary. And also use the methodologies I have used for my PhD to other groups like lissamphibians and sharks.

RA: This is a broad question that I have also made to Paul. What is lacking in the Vertebrate Paleontology community?

PM: mmmhh.. We need sauropods to be feathered! [laughs] I think it is getting better, people are applying better methodologies and using things like statistics… more and more people are getting more rigorous with their analysis. Nevertheless, I think people shoud be more rigorous in terms of ages of formations, there are lots of problems in places in China for example. But I think there is still a lot of scope for many avenues in paleontology…

RA: What is a typical day for you as a paleontologist?

PM: A typical day will, at the moment, largely involves me processing large amounts of data through my database of sauropod occurrences and testing it from various criteria to do things like environmental associations, and gradually – somewhat groovenly – writing up my thesis. When I am not doing something directly related with my thesis I am writing descriptive papers, or sometimes coming to Museums like Lourinhã to study specimens.

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