Geological time and ecological principles (August 27 & 29)

Our very first topic is geological time. Paleoecology is a historical science, so it needs a chronological system. Generations of geologists have crafted the iconic Geologic Time Scale, which will be critical to all that we do in this course. Here isĀ our version of the Geological Time Scale. Like geologists and other Earth scientists before you, please memorize all the eon, era, period and epoch names given on our chart. (Here is the latest professional version of the time chart. You don’t need to know all those other names!)

I don’t want to overwhelm you with ecological terms from the Web. We will develop those we need within our own conceptual context. This pdf from Dr. Karen Lancour on ecological principles, though, is a nice summary. You certainly don;t need all that she has included; concentrate on her illustrations now and then return for some of the definitions. A more philosophical view is in these Ten Principles of Ecology.

Geology in the News —

There is now some resistance too the concept of a human-initiated geological time interval: The Anthropocene is a Joke. A bit harsh, but thoughtful.

There is an interesting new idea about why oxygen levels plateaued for almost two billion years during the Proterozoic. Oxygen may have limited nitrogen fixation until the appearance of land plants kick-started photosynthetic oxygen production in a big way.

Speaking of oxygen, could rising levels of atmospheric oxygen have helped increase North American dinosaur diversity? The evidence looks thin to me, but it may be a cool hypothesis to test.