\ Visualizing Evolution: Dinosaur Supertree

Wednesday, July 23, 2008

Dinosaur Supertree

I think this is my first time posting twice in one day, but I simply couldn't wait until tomorrow to share the dinosaur evolutionary tree that was just published in the Proceedings of the Royal Society B. (The "B" is for "Biological Sciences").

click for really, really big

In the New Scientist article, paleontologist Graeme Lloyd of the University of Bristol explains how they used existing dinosaur cladograms from the literature to compile 440 of the 600 known species into a single diagram, in order to look for larger patterns of diversification.

What they concluded was that dinosaur diversity did not expand as actively as previously thought and that the main bursts of diversification happened in the first fifty million years of dinosaur evolution. Unfortunately, the diagram itself doesn't include an intersecting timeline to show when each of the diversification events occurred--I suppose either to save space or perhaps due to conflicting or missing information within the clades that were gathered to build this one.

The height of each major branch is dependent not on the relative time in which it branched off, but rather the number of branching events within the branch itself. (Did I say "branch" enough there? *sigh*) So although it's an awesome tree, and probably totally useful as a reference, I'm not sure how it shows the patterns of diversification they report to see. But perhaps I'm missing something. Perhaps I'm simply still mesmerized by the pretty colors. So pretty...

edit: I swapped the .jpg-artifact-riddled image from the news report with a cleaner one I made from the original pdf file. If you want the full version (to print out or whatever), I've uploaded the pdf here. Which I originally found here, on Physorg.com's article.


Harrison said...

That tree, is in fact, round.

Harrison said...

I put my ,'s in the wrong spots.

Heidi Richter said...

Yes, the tree, is round for, a reason.

If it helps, imagine it as a regular phylogenetic tree, but in 3-dimensions, and then fly up and look at it from above. When you look down on trees they are round.