I'm glad to see some action lately, it's been too quiet around here. As a
plant biologists it always appears that plants get shortchanged in the
discussions. Given the recent discussion of the Cambrian explosion, I
thought I would offer up something from a paper I just finished reading.
EARLY EVOLUTION OF LAND PLANTS: Phylogeny,
Physiology, and Ecology of the Primary Terrestrial
Radiation Annual Review Ecol. Syst. 1998, 29:263-292
For full text see:
http://biomedical.AnnualReviews.org/cgi/content/full/4/29/263
I will just copy the abstract and one other paragraph from the paper:
Abstract:
The Siluro-Devonian primary radiation of land biotas is the terrestrial
equivalent of the much-debated Cambrian "explosion" of
marine faunas. Both show the hallmarks of novelty radiations (phenotypic
diversity increases much more rapidly than species
diversity across an ecologically undersaturated and thus low-competition
landscape), and both ended with the formation of
evolutionary and ecological frameworks analogous to those of modern
ecosystems. Profound improvements in understanding early land plant
evolution
reflect recent liberations from several research constraints: Cladistic
techniques plus DNA sequence data from extant relatives have prompted
revolutionary reinterpretations of land plant phylogeny, and thus of
systematics and character-state acquisition patterns. Biomechanical and
physiological
experimental techniques developed for extant plants have been extrapolated
to fossil species, with interpretations both aided and complicated by the
recent
knowledge that global landmass positions, currents, climates, and
atmospheric compositions have been profoundly variable (and thus
nonuniformitarian)
through the Phanerozoic. Combining phylogenetic and paleoecological data
offers potential insights into the identity and function of key
innovations,
though current evidence suggests the importance of accumulating within
lineages a critical mass of phenotypic character. Challenges to further
progress
include the lack of sequence data and paucity of phenotypic features among
the early land plant clades, and a fossil record still inadequate to date
accurately certain crucial evolutionary and ecological events.
A portion of the second paragraph of the paper:
"Any uniformitarian views of the Earth's environment that have survived the
paradigm shift of plate tectonics and continental drift have since been
undermined by evidence of dramatic changes in global climate and
atmospheric composition through the Phanerozoic. Thus, paleoecologists must
now
deal with profound changes in the environmental theater as well as the
evolutionary play. During the Siluro-Devonian there was a strong
concentration of land masses in the Southern Hemisphere, with only North
America, northern Europe, and parts of China straddling the equator (115).
Consequently,
both atmospheric and oceanic currents contrasted starkly with modern patterns."
I thought this was a good example reference to uniformitarianism in a
modern context. I have used this quote to point creation scientists to the
fact that modern uniformitariansm is very different that that of the late
1800s and early 1900s.
Joel Duff