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No Fungus Amongus

Published: February 8, 2011

We mammals tend to run hot. A new theory suggests an evolutionary reason: the age-old battle of animal (or plant) vs. fungus.

Scientists report (and it is news to this correspondent) that a “fungal bloom” swept the earth about the time the age of the reptiles came crashing down, i.e. the extinction of the dinosaurs. Combined with the fact that that plants, insects and cold blooded creatures suffer more from fungal attacks than animals with breasts (it’s what makes us mammals) or feathers. Is it the body heat of mammals and birds that help us ward of the fungi?

Some bright sparks have determined that the optimal temperature to discourage a fungal infection is 36.7 degrees C, just a half degree Fahrenheit below human body temperature. Coincidence? Maybe not. To keep our fires stoked we burn a lot of fuel. If we burned hotter we could ward off more fungi, but the costs of finding the extra food would be a trade-off.

If virtually all the large reptiles died off 63 million years ago, killed by some combination of asteroid strike in Yucatan, lava flows in India, disease migrations over new geography, then why didn’t smaller reptiles just re-take the earth instead of mammals and birds? After all, snakes and lizards pop out lots of offspring while the likes of us furry creatures raise much smaller batches. You’d think they’d hold the reproductive edge. Hmmm maybe there is something to all this.

The Fungal Biodiversity Center in the Netherlands (and who knew they existed) tested the thermal tolerance of 4800 types of fungi. Every degree above 30 C (which is 86 F) they found 6% fewer species could grow, meaning by the time one gets to human body temperature almost half of fungi could simply not act as pathogens.

Pretty interesting juxtaposition of medicine and evolutionary biology with paleontology, eh?

But where does this story about a fungal bloom 60 million years ago come in. Please write in if you know anything about this fascinating tid-bit. We have never heard of this item.