Biology Reference
In-Depth Information
10
Pole to Pole
A Walk over the Landscape,
a Walk through Time
As a means of conceptualizing the greening of the New World from
the Cretaceous through the Cenozoic, I envision an imaginary
walk from pole to pole at four critical stages in the evolution of the
ecosystems: at 100 Ma, near the time of low elevations, maximum
Cretaceous warmth, and high sea levels; at 55 Ma during the peak
of the even warmer Late Paleocene Thermal Maximum / Early Eo-
cene Climatic Optimum (LPTM/EECL); at 17 Ma with the begin-
ning of the Miocene temperature decline, decreasing atmospheric
moisture, and a change toward enhanced seasonality; and at 2 Ma
near the beginning of ice age climates and widespread glaciations.
Four features of the ecosystems will be considered for each time
segment—climate, landscape, fauna, and fl ora.
ONE HUNDRED MILLION YEARS AGO
If one were standing on the shore of the Arctic Ocean in the Mid-
dle Cretaceous, two aspects of the surroundings would be familiar.
