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Blame sauropods for pine cones!



From: Ben Creisler
bh480@scn.org

A new theory about why bulky, spiky conifer cones evolved:

Dinosaur Munchies May Have Bulked Up Pine Cones
http://news.sciencemag.org/sciencenow/2011/02/dinosaur-munchies-may-have-bul
ke.html?ref=hp

and

Andrew B. Leslie (2011)
Predation and protection in the macroevolutionary history of conifer cones.
Proceedings of the Royal Society B (advance online publication)
DOI: 10.1098/rspb.2010.2648 
http://rspb.royalsocietypublishing.org/content/early/2011/02/17/rspb.2010.26
48.abstract?sid=c44481d1-94e9-4c50-ab37-9123407072d6


Conifers are an excellent group in which to explore how changing ecological
interactions may have influenced the allocation of reproductive tissues in
seed plants over long time scales, because of their extensive fossil record
and their important role in terrestrial ecosystems since the Palaeozoic.
Measurements of individual conifer pollen-producing and seed-producing
cones from the Pennsylvanian to the Recent show that the relative amount of
tissue invested in pollen cones has remained constant through time, while
seed cones show a sharp increase in proportional tissue investment in the
Jurassic that has continued to intensify to the present day. Since seed
size in conifers has remained similar through time, this increase reflects
greater investment in protective cone tissues such as robust, tightly
packed scales. This shift in morphology and tissue allocation is broadly
concurrent with the appearance of new vertebrate groups capable of browsing
in tree canopies, as well as a diversification of insect-feeding
strategies, suggesting that an important change in plant?animal
interactions occurred over the Mesozoic that favoured an increase in seed
cone protective tissues. 



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