January 9th, 2008

Red dress
  • gemfyre

Christmas in Australia

Mistletoe is generally associated with Christmas. And an Australian bird and plant are only too willing to get into the Christmas spirit.

First is a tiny bird called the Mistletoebird (Dicaeum hirundinaceum). The males even resemble a Christmas decoration.

Photo by David Kleinert

The Mistletoebird can be found anywhere mistletoe grows, which is almost everywhere. Most Australian mistletoes mimic the leaves of the tree which they parisitise, but once you get your eye in the distinctive drooping leaves and yellow or reddish colour (not to mention the distinctive red flowers) give it away upon a eucalypt or acacia. Anyway, the Mistletoebird feeds on the fruits of the mistletoe. These fruits are rather sticky and the mistletoebird's digestive system isn't very long - thus once the seed within the fruit comes out the other end of the bird, it's still covered with sticky fruit flesh. To dislodge this from their back ends the Mistletoebird's perform a rather amusing little dance upon a tree branch, where they drag their rear ends along a branch. Of course, the seed now sticks to a branch of a potential host tree. So the mistletoe and the mistletoebird remain dependant on one another.

Also in Australia, mainly in the south-west, there is a plant called Nuytsia floribunda which many locals refer to as the Christmas Tree because it flowers near Christmas.

Photo by O. Roberts

What many don't realise is that the Christmas Tree is also a mistletoe (adding to it's Christmasyness). It parisitises the roots of nearby trees, thus being able to form a tree like habit itself. This plant has been the bane of telecommunications and electricity companies in the past. Sometimes underground lines would go out for no discernable reason, but further research revealed these lines had been cut - by the Nuytsia! To the Nuytsia's parisitic roots an underground cable would feel just like a tree root, so the mistletoe had put out it's own strangling roots and inadvertantly cut the line.
  • drhoz

B-Movie Monster Fungus, Part 1

another older post of mine, from my many "education even if you don't want it" posts, this time under the "funguuz" tag, but with a heap of additional info I've compiled for your amusement.

For over a 150 years now, weird fossils have been turning up in 400 Million-year-old rock. They're up to 9 metes long, and resemble petrified trunks of yew trees, Taxus, hence the name Prototaxites. They're not even that rare, particularly in eastern Holland.

But they certainly weren't conifers. For one thing, they dwarfed anything else on the land at the time.

Prototaxites has turned out to be a fungus. A really big, really really big, fungus.

C. Kevin Boyce and his collaborators relied on isotopic analysis of carbon-12 and carbon-13. In photosynthetic organisms, the composition correlates with the isotopic composition of CO2 in the atmosphere, and don't vary by more than 2 to 4 parts per thousand.

Prototaxites broke the mold. (ho-ho, a pun) "We find a difference of 12 parts per thousand," says Boyce, which means Prototaxites was not photosynthetic, and therefore was not an autotroph - a primary producer. Instead, it was a heterotroph - a consumer of biological material made by other organisms. "If you are a heterotroph, you can be all over the place".

Modern fungi consume many types of dead stuff, and Prototaxites may have eaten whatever it could get its hyphae into. Although terrestrial plants were evolving and spreading fast when Prototaxites was dominating the landscape, some of the Prototaxites fossils have isotopes inconsistent with consuming vascular plants. The most likely alternative is cryptobiotic soil, a crust containing bacteria (including cyanobacteria), lichens, mosses, green algae and fungi - an ecosystem that is now found mostly in deserts.

"Even though most of these organisms are photosynthetic, different species, even in a particular location, have different ratios of carbon isotopes" Boyce says, "which explains the varying C-12/C-13 ratios in Prototaxites." Because cryptobiotic crusts do not fossilize, isotopic analysis of Prototaxites becomes a unique lens into the Devonian landscape. "These fungi show us that well into the period of diversification of vascular plants, there are still large areas of microbial activity."
Cat on the brain

(no subject)

These are pictures of an actual polar bear attack in Churchill.

They were taken while people watched and could do nothing to stop the attack.

Reports from the local newspaper say that the victim actually survived.

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