Lack of Molybdenum May Have Delayed Life on Earth

esocid writes "Scientists from around the world have reconstructed changes in Earth's ancient ocean chemistry during a broad sweep of geological time, from about 2.5 to 0.5 billion years ago. They have discovered that a deficiency of oxygen and the heavy metal molybdenum in the ancient deep ocean may have delayed the evolution of animal life on Earth for nearly 2 billion years. Bacteria cannot fix nitrogen efficiently when they are deprived of molybdenum. And if bacteria can't fix nitrogen fast enough, then eukaryotes — a kind of organism that includes plants, pachyderms and people — are in trouble because eukaryotes cannot fix nitrogen themselves at all. Ariel Anbar, a co-author of the research of Arizona State University, stated that "eukaryotes depend on bacteria having an easy enough time fixing nitrogen that there's enough to go around. So if bacteria were struggling to get enough molybdenum, there probably wouldn't have been enough fixed nitrogen for eukaryotes to flourish.""

Re:42

[Silicon Jedi]

Holy crap! There are 42 protons in its nucleus!

Re:42

[rangek]

Holy crap! There are 42 protons in its nucleus!

You dope. That is what the atomic number means.

Re:terraforming and other things

[dokebi]

Nitrogen is part of both DNA and amino acids. Therefore all life as we know it requires it. We can speculate about other types of lifeforms that doesn't use DNA, but as far as we know the, nitrogenases are the only enzymes that takes nitrogen gas to a usable form (ammonia).

It is important to realize that life on earth didn't all come to existence at once. Animals cannot breath CO2 not because it can't evolve for it but because our metabolism depends on oxygen. Without plants fixing CO2 and putting out O2, *for millions of years*, animals couldn't exist. Plants couldn't evolve to fix nitrogen in the similar way. Read up on the nitrogen cycle.

BTW, IMAB (I am a biologist).

Re:Excitement

[mikael]

Not necessarily. The use of bitumen/tar was documented in biblical times [ourfatherlutheran.net]. The Romans were thought to have used coal for metalwork [wiganarchsoc.co.uk]. A Greek by the name of Heronas, developed a prototype steam engine. [e-telescope.gr] They might have advanced faster technologically, if they weren't afraid of making the slaves unemployed [mlahanas.de]

You can also read the history of the combustion engine [about.com]. The first combustion engines were based on gunpowder, then coal powered steam engines, coal gas, and finally petroleum. At the same time, engineers experimented with one stroke, two stroke and four stroke engines with vertical and V slant pistons.

Re:Interesting thought for a sci-fi novel

[Anonymous Coward]

Presumably Niven didn't anticipate the Pak when writing World of Ptaavs. But there's not really any need to retcon. Characters in World of Ptaavs assumed that humanity evolved from Slaver food species on Earth. They were just slightly wrong. Food species on Earth did become highly evolved, but never became intelligent. The Pak evolved from the same sort of food species growing on a distant planet. A Pak colony was sent to Earth and somehow became lost, and then Homo sapiens evolved from the remnant of that colony.

The real problem is the coincidence between the evolution of apes on earth, and the Pak from their homeworld. This is a problem regardless of the Slaver backstory. As far as I know there is no good explanation for this in Niven's universe... but I could be wrong.

model T

[Anonymous Coward]

never send a chemist to a gearhead discussion, it's like jack knife vs pistol

Model T, 1909-27 designed to run on corn and hemp ethanol (Henry really disliked petroleum fuels, thought they were dirty and disgusting, liked nice clean and clear corn squeezings better), prohibition basically finished off ethanol as a fuel, although it was semi popular up until then, albeit as a blend with regular gasoline, already the petroleum exploiters were pushing their way in to total control. Incidentally, later on he also championed hemp for plastic bodies on cars instead of sheet metal. Once again planned obsolescence and the lobbying of some big corporations killed off the "tough as nails and no rust" idea.

The dude was generations ahead of his time really on the "big picture" side of things. Also helped bring about a serious urban middle class with his "pay your workers well, enough so they can afford the products they make", a formula that worked quite well until the current crop of wall street snakeoil salesmen decided that outsourcing out of their own nation-screwing over all their own potential customers- was a better idea. Pretty funny to watch them try to explain what is going on now with their credit and derivatives gambling losses..no way can anyone honest call them "investments"...

Re:terraforming and other things

[thepotoo]

Nope. You lose. Bacteria/Prokaryotes/lots of protolife evolved first. I don't have a Biology textbook in front of me, but here [wmnh.com] is an online reference. IAAB (student)

Re:terraforming and other things

[thepotoo]

Sigh. [google.com] How hard did you look, exactly?

(Mo is used as a cofactor, meaning that it can be used over and over again without being depleted. You just need a single atom of Mo per enzyme.)

Re:Excitement

[sm62704]

The Romans were thought to have used coal for metalwork

I didn't know that there was any other way besides coal/coke for the ancients to have done blacksmithing, although wikipedia says it can be done with charcoal. I have no idea how charcoal would work. The Wikipedia article isn't quite accurate:

Blacksmiths work by heating pieces of wrought iron or steel in a forge until the metal becomes soft enough to be shaped with hand tools, such as a hammer and chisel. Heating is accomplished by the use of a forge fueled by propane, natural gas, coal, charcoal, or coke.

You can't blacksmith using just coal; the coal is turned to coke [wikipedia.org] by oxygenating it with a blower, and pouring water on it. At least that's what they taught in my college blacksmithing class. I can't remember the fellow's name, unfortunately, but he was 72 at the time and travelled to different universities teaching his dying art to the younger generation. This was some time in the late 1970s. He'd smithed Gerald Ford's wrought iron fence, at the time of the class Carter was president.

I really should build a forge.

Re:Eukaryotes

[Blastercorps]

Compared to prokaryotes [wikipedia.org] (simple life, bacteria), all eukaryote life [wikipedia.org] (advanced life like plants pachyderms and people) are essentially cousins. This is a split that happened at the dawn of life on earth. This article theorizes that the split would have happened earlier if not for a lack of molybdenum and the resultant lack of usable nitrogen.