Friday, August 7, 2009

The Occasional Fossil

Fossil Wasp (NOT to scale!) from Eocene lake beds at Florissant Fossil Beds National Monument. (photo by Bud Wobus).

Very dang cool. Link goes to the original photo.

Very Good Book

Dave Raup, an excellent paleontologist has written a very good book on extinction that does a good job of dealing with some of these counting issues. It's called "Extinction Bad Genes or Bad Luck. " The link takes you to Amazon. I can't seem to find my copy so I'll be ordering another one.

Thursday, August 6, 2009

Anciennt Versus Modern Extinction Pt 3

The word extinction means we have fewer plants and animals than we did before. So we're going to need to count things. But what are we counting? Species? Here's a dirty little secret: Paleontologists don't really have a good species concept. Biologists have a pretty good one.
The biological species concept defines a species as members of populations that actually or potentially interbreed in nature, not according to similarity of appearance.
To that we probably need to add that the offspring can, themselves, reproduce but you get the idea. Here's the problem.... "similarity of appearance" is really all we have in Paleontology. You take two fossils, put then on a water bed, give them some privacy and cue the Barry White. Come back a month later and there are still just going to be two fossils there. FOSSILS DON'T REPRODUCE. In fact we can't be really sure those two fossils were the opposite sex. (not that there's anything WRONG with same sex fossils) . So what do we do about the species concept in paleontology?... basically we muddle through as best we can mainly relying on appearance.
The diversity curve we've been looking at is a family level curve not a species level curve. For those of you who are taxonomically challenged remember that species' group into genera and genera group into families. Not all families have the same number of species. A family of insects may have hundreds of species. The family we belong to, Hominidae contains us, gorillas, chimpanzees and orangutans. So taking out a family of insects takes out a whole lot more species than taking out a family of primates.
So you've got a bunch of biologists out there defining extinction by counting species and you've got paleontologists counting what are basically morphoptypes. And really most of our work on broad patterns in extinction and radiation is done two taxomic levels up. Comparing those is gong to be very very tricky.
Next up: Taphonomy. Because if you don't understand that you don't understand anything.

Wednesday, August 5, 2009

Getting ready for some content

So I was sitting around musing about my lack of blogging. I've honestly never been able to get over the the "who really cares about what I have to say"hump. But I was feeling a bit guilty for the people who do read.. coming to the blog.. no new content... over and over... but then I realized wait a sec.... no one goes to blogs any more it's all about the RSS so here I am in your RSS feed... taking up space.
The point of this really though (you knew there had to be a real point somewhere didn't you) is that I'm about to post up another entry on modern versus ancient extinction and RSS feeds don't usually show past posts. So if you care, go back and read the first two again so you know what the heck I'm talking about. I know I'm going to have to.
The first is here
the second is here

And just random bit. If you're not reading Isis the scientist you should be.