The occasional concept.

Taphonomy
Taphonomy is the paleontologists way of saying "shit happens" generally to the fossils ~I'm~ trying to study. (Yes we take it personally:) In a perfect world a Thompson's Gazelle, for example, dies of a heart attack while drinking at a river, it falls into the river where it is covered with fine grained sediment and is perfectly preserved intact until a paleontologist comes along and digs it up. This never happens. Thompson's Gazelles don't die of heart attacks, they die of Lion bites to the throat, after which they are scattered by the Lions all over the Serengeti. If they do fall into the river they're torn apart by crocodiles once the bones are buried there are all sorts of chemical processes that can degrade the bone so by the time we get to it there's usually not much left.
Taphonomy was once described to me as the loss of information in the fossil record. I'm not quite that pessimistic. For example, if your fossil shows signs of being eaten by crocodiles then you know that there were crocodiles around. But I'm a paleoecologist so I'm into that sort of thing.
Regardless, taphonomy is the transition from the life assemblage, which is all the biology going on in a certain area, to the fossil assemblage, which is what the paleontologist finds in the rock record. If you don't understand taphonomy you don't understand anything in paleo.

more to come....