Wow, that PETM event is fascinating. Thanks again.
http://gsa.confex.com/gsa/2002AM/finalprogram/session_2785.htmThe origin of __PRIMATES__ is linked to this!
"Body size dwarfing in Wa-0 mammals cannot be explained as a response to temperature alone, and elevated atmospheric CO2 probably played an important role. Body size is influenced by food quality. Experiments with plants grown in CO2-enriched atmospheres (double present levels) yield enhanced photosynthesis, with more carbon and less nitrogen in plant tissues. The extra carbon enhances production of secondary compounds, inhibiting digestibility. CO2 enrichment reduces rubisco enzyme in foliage, decreasing leaf protein and lowering nutritional value for herbivores, which causes the herbivores to grow more slowly. Slower growth, coupled with any of the usual seasonal temperature, rainfall, or day-length effects controlling reproductive cycles, would lead to reproduction at smaller body size. Such an explanation involves temporary and reversible environmental selection leading to a transient evolutionary dwarfing response.
Faunal changes lagged onset of the CIE by some 13 and 22 k.y., consistent with the idea of a stepped response to climate change. In Wyoming, endemic Meniscotherium appeared in the first step of response some 13 k.y. after initiation of the CIE.
Cosmopolitan Artiodactyla, Perissodactyla, and __PRIMATES__ appeared in the second step, some 9 k.y. later, at about the time they appeared on all three northern continents.
Climate change can have profound and lasting effects on mammalian faunas."
Profound, eh?
~samwik
