September 25th, 2008

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Yeah, Canada!

Rocks May Be Oldest on Earth, Scientists Say

A swath of bedrock in northern Quebec may be the oldest known piece of the Earth’s crust.

In an article appearing in Friday’s issue of the journal Science, scientists report that portions of that bedrock are 4.28 billion years old, formed when the Earth was less than 300 million years old.

“These rocks paint this picture of an early Earth that looked pretty much like the modern Earth,” said Richard Carlson of the Carnegie Institution of Washington and one of the authors of the paper.

Other scientists are intrigued, but not yet entirely convinced that the rocks are quite that old.

“There is a certain amount of healthy skepticism that needs to play a role here,” said Stephen J. Mojzsis, a professor of geological sciences at the University of Colorado. Dr. Mojzsis said the new research was well done, but that he thought these were younger sedimentary rocks, pressed together out of the remnants of earlier rocks that were indeed 4.28 billion years old.

Rest of the article here:

aye aye captain
  • drhoz

T Minus Ten. Nine. Eight....

Been too long since I've done a parasite post, so...

Lungworm! And Fungus Cannon!

Dictyocaulus is a genus of nematode worms, parasitic upon large herbivores including cattle, elk, deer, horses, and donkeys. They spend most of their life in the lungs, causing the disease 'Husk'. Their eggs, however, get coughed up and swallowed, and hatch into L1 stage larvae. These do fine in the feces, and pass through a second and third stage once they get their first taste of the outside world. But they still need to get from the cowpat back into the cow, which present problems.

Because most animals avoid eating anywhere near their own faeces. Even without lungworm to worry about, there are plenty of other diseases that could make it a case of "Eat Shit And Die" ( eating somebody else's shit presents fewer problems, and indeed plenty of animals will happily get stuck in for the extra nutrients - and koalas wean their babies onto half-digested gumleaves ).

But back to the little L3 lungworms, looking for a way to get from the meadow muffin to some nice tempting grass a good way off. Fortunately, they have a short cut.

Because one of the other temporary gut inhabitants is the fungus Pilobolus. This zygomycete just wants to get from pasture patty to pasture patty, and the best way to do it is via the cow. But then it faces the same problem the worm does - trying to get far enough from the landmine it's in to clean grass somewhere over there. Pilobolus' solution is to bundle it's spores into a neat little capsule at the end of a stalk, and fire it off at 180,000g's.

Thankyou </b></a>hayleyscomet for doing the vid, and anjel_kitty for the news, via the mycology group.

The stalks will point directly at the sun, too, the launch bulb doubling as a lens to indicate the best growth direction for the cells below. Even neater, the sporangiums are covered in calcium oxalate crystals on one side, so if they land in a dew drop they flip over and stick down properly.

So, with these spore capsules a mere centimeter overhead, then flying off up to 2 meters (or ricocheting noisily off the lid of the box in the lab ) all the little lungworms have to do is climb the launch tower and get on board. No doubt they have The Right Stuff, because lungworm remains a serious disease of many large domestic herbivores.