Biology Reference
In-Depth Information
Figure 9.5
Pollen records from the lowland
forest of Carajás, Brazil, for trees (A), grasses
(B), and Asteraceae/Compositae,
Borre-
ria,
and
Cuphea
(C). Note the fl uctuations
between arboreal pollen (AP) and nonar-
boreal pollen (NAP). From Hooghiemstra
and van der Hammen 1998. Used with
permission from Elsevier Science Publishers,
Amsterdam.
discussed and refi ned, but in my opinion it remains a viable theory requir-
ing continuing revision.
POINTS IN TIME
I have suggested that although geologic, climatic, and biologic histories are
a continuum, there are times when events and processes combine to favor
one kind of lineage or ecosystem over another. After the origin of the angio-
sperms in the Early Cretaceous circa 135 Ma (appearance of monosulcate,
columellate dicot or monocot pollen), and the eudicots around 125 Ma (tri-
