One of the reasons I started this blog to was to give myself an opportunity to write about issues in paleontology and science in general. Things have been a bit light on that front so today I start a new feature: Paleo 101, just a very brief run through of what paleontology is and what paleontologists do. There are a lot of misconceptions out there . I aim to clear them up, at least among my readership (all three of you).
Ok first things first, what is paleontology?
Paleontology is the study of the history of life.
This is a pretty good definition but it's awfully broad and could be taken to mean a variety of things. So lets talk for a moment about what paleontology isn't. Paleontology isn't Archeology. We don't care about ancient civilizations, temples, pyramids, arrowheads any of that stuff. Once humans evolved to the point where they are "anatomically modern" we no longer care about them, that's where Archeology picks up. In fact, the study of human evolutions is paleoanthropology and is usually studied by people who are more anthropologists than paleontologists.
Paleontology is not the study of fossils. Although fossils are the primary tool we use there is much more to it than that. Nor is paleontology the study of dinosaurs. There is a LOT more to the history of life than just dinosaurs.
Life on earth goes back about 3 billion years. On both ends of this things get a little hinkey. (if you want to be a paleontologist you have to learn technical terms like hinkey) Let's say you're walking along the beach and you find a shell.
1) Is it a fossil? and
2) would a paleontologist be interested?
In order 1) probably not. Fossils are usually older than the shells you find on the beach (although there are places where fossil shells are washing up on beaches). Exactly how old something has to be in order to be considered a fossil is open to some debate but just about everyone agrees that most shells on the beach aren't. Also, fossils have usually undergone some sort of physical or chemical modification that has allowed them to remain intact for thousands to billions of years. Shells on the beach haven't.
2) Maybe so. Even though it's not a fossil, paleontologists spend a great deal of time studying the patterns and processes of life in modern environments in order to understand what's happening in ancient environments. If your shell is abraded or broken or fell victim to a predator of some kind or is laying in a bed in a particular way with a bunch of other shells we may be very interested in it. The philosophical underpinning for this way or doing science is called uniformitarianism which is such an important concept that we'll have a post on just that in the near future.
On the other (hinkey) end, the oldest undisputed fossils look something like this:
Got it? That's a fossil. It's a stromatolite. A mat of sediment that was trapped by a microbial community then was turned into rock. We know it's biological in origin because it has a particular chemical signature. This is the thing with really old fossils, we're not dealing directly with the remains of a organism we're dealing with the chemical signature of the organism in the rock. Consequently, you'll find a lot of disagreement out there as to how old the oldest life actually is.
Ok that'll wrap us up for today. Next time: Uniformitarianism.
This is a crinoid, an animal vaguely related to starfish, sea urchins and sand dollars. They are not extinct, but they are not nearly as common as they used to be. There was a time when the bottom of the continental shelf was teaming with these things, now they seem to be mostly restricted to hyper saline environments. Below I have a reconstruction.
Once again this is an animal, it moves using a water vascular system, it can pump water in and out if it's various parts and when it does so it moves. In graduate school I was once caught in an argument between two professors about whether or not the water vascular system extends all the way to the bottom of the animal. I knew enough to keep my mouth shut. (I just hmmmmed and nodded a lot)
