Journal Entry 5(Chapter Five)-Ziomara Aguilar

Science historian Thomas Kuhn reasons that humans have been forced to adapt to changing environments. They will try old methods to see if they will work in their new environment before trying a new method. This is known as the paradigm shift (a fundamental in basic concepts and experimental practices of a scientific discipline). Kuhns work is a tool for analyzing the different ways the different ways scientists develop mass extinction.

Kolbert goes to the Scottland Highlands and meets with Jan Zalasiewickz, a stratigrapher(a scientist who studies different eras of planetary history). He shows layers of rock that date back 445million years ago(the time period following the dinosaur extinction). This rock layer is from the Ordovician Era which is the time period when sea life grows rapidly and coral reefs begin to form. Halfway through this era, mossy plants begin to appear on land. And by the end of the era, 85% of the ocean life has gone extinct. The current theory is that glaciation many of the species. Carbon dioxide levels had dropped during this time causing the temperatures and sea levels to drop. Evidence suggests that the mossy plants were the cause of the carbon dioxide levels to drop.