Nagelly's Journal Entry #1

Prologue:

    In the prologue, Elizabeth Kolbert introduces the idea of Earth having another mass extinction.  She says that their have been five major ones already, the  Ordovician-Silurian mass extinction, the Late Devonian mass extinction, the Permian mass extinction, the Triassic-Jurassic mass extinction and the Cretaceous-Tertiary mass extinction.  Kolbert says that theses mass extinctions were just that, massive. A great deal of diversity dropped in each of theses extinctions and she believes that earth is due for another mass extinction. Kolbert puts  emphasis on human activity on Earth, Kolbert said, " no creature has ever altered life on the planet in this way before, and yet other comparable events have occurred" (pg2) . This is important because the changes that humans are making can lead to an even more catastrophic event. I had to question this just because I wondered why there hasn't been a mass extinction yet. I wonder how a mass extinction works. Do species just suddenly become extinct? Kolbert also explained in the prologue that there have been many back ground extinctions that prove her theory. She explains them in great detail in the following chapters. In the prologue, as the quote shows, Kolbert connects to the theme that humans alter natural systems. Humans are changing the composition of the atmosphere and it causes a shift in natural systems. Humans are raising the seas levels and forcing animals to migrate away from their homes. This can have grave impacts on present ecosystems.