Australian vegetation 40 to 50 million years older than thought?
|December 10, 2015||Posted by News under Intelligent Design, News, Plants, stasis|
From Science Daily:
New fossil evidence shows that Australia’s fire-prone shrubland open vegetation originated at least 70 million years ago — 40-50 million years earlier than previously thought.
The findings, published online ahead of print in the American Journal of Botany, reject prevailing wisdom that Australia was covered with rainforest until 40 million years ago, and that currently dominant native vegetation types evolved after that on a drying continent with increasing fire.
“Amazingly, we think part of the ancient vegetation was similar to what you can now see in south-western Australia, and there were even a couple of leaf bits that look just like Banksia,” says Dr Carpenter.
“Banksia is one of Australia’s most iconic native plants and is very often associated with fire. Somehow this family of plants has shown extraordinary persistence over an incredibly long period of time, through extremely variable climatic conditions.” More.
Yes, stasis is amazing.
Every time something complex turns out to be “older than thought,” the amount of time for Darwinian evolution (natural selection acting on random mutation) to work magic by generating huge levels of information rather than noise is diminished. That old top hat may be running out of rabbits (though maybe not true believers).
See also: Stasis: Life goes on but evolution does not happen
Talk to the fossils: Let’s see what they say back
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Here’s the abstract:
PREMISE OF THE STUDY: The origin of biomes is of great interest globally. Molecular phylogenetic and pollen evidence suggest that several plant lineages that now characterize open, burnt habitats of the sclerophyll biome, became established during the Late Cretaceous of Australia. However, whether this biome itself dates to that time is problematic, fundamentally because of the near-absence of relevant, appropriately aged, terrestrial plant macro- or mesofossils.
METHODS: We recovered, identified, and interpreted the ecological significance of fossil pollen, foliar and other remains from a section of core drilled in central Australia, which we dated as Late Campanian–Maastrichtian.
KEY RESULTS: The sediments contain plant fossils that indicate nutrient-limited, open, sclerophyllous vegetation and abundant charcoal as evidence of fire. Most interestingly, >30 pollen taxa and at least 12 foliage taxa are attributable to the important Gondwanan family Proteaceae, including several minute, amphistomatic, and sclerophyllous foliage forms consistent with subfamily Proteoideae. Microfossils, including an abundance of Sphagnales and other wetland taxa, provided strong evidence of a fenland setting. The local vegetation also included diverse Ericaceae and Liliales, as well as a range of ferns and gymnosperms.
CONCLUSIONS: The fossils provide strong evidence in support of hypotheses of great antiquity for fire and open vegetation in Australia, point to extraordinary persistence of Proteaceae that are now emblematic of the Mediterranean-type climate southwestern Australian biodiversity hotspot and raise the profile of open habitats as centers of ancient lineages. (paywall) – R. J. Carpenter, M. K. Macphail, G. J. Jordan, R. S. Hill. Fossil evidence for open, Proteaceae-dominated heathlands and fire in the Late Cretaceous of Australia. American Journal of Botany, 2015; DOI: 10.3732/ajb.1500343