Evolution observed in a lab

Atomic_Piggy

Atomic_Piggy

Newbie
Joined
Apr 26, 2006
Messages
6,485
Reaction score
2
http://www.newscientist.com/article/dn14094-bacteria-make-major-evolutionary-shift-in-the-lab.html

A major evolutionary innovation has unfurled right in front of researchers' eyes. It's the first time evolution has been caught in the act of making such a rare and complex new trait.

And because the species in question is a bacterium, scientists have been able to replay history to show how this evolutionary novelty grew from the accumulation of unpredictable, chance events.

Twenty years ago, evolutionary biologist Richard Lenski of Michigan State University in East Lansing, US, took a single Escherichia coli bacterium and used its descendants to found 12 laboratory populations.

The 12 have been growing ever since, gradually accumulating mutations and evolving for more than 44,000 generations, while Lenski watches what happens.

Profound change
Mostly, the patterns Lenski saw were similar in each separate population. All 12 evolved larger cells, for example, as well as faster growth rates on the glucose they were fed, and lower peak population densities.

But sometime around the 31,500th generation, something dramatic happened in just one of the populations ? the bacteria suddenly acquired the ability to metabolise citrate, a second nutrient in their culture medium that E. coli normally cannot use.

Indeed, the inability to use citrate is one of the traits by which bacteriologists distinguish E. coli from other species. The citrate-using mutants increased in population size and diversity.

"It's the most profound change we have seen during the experiment. This was clearly something quite different for them, and it's outside what was normally considered the bounds of E. coli as a species, which makes it especially interesting," says Lenski.

Rare mutation?
By this time, Lenski calculated, enough bacterial cells had lived and died that all simple mutations must already have occurred several times over.

That meant the "citrate-plus" trait must have been something special ? either it was a single mutation of an unusually improbable sort, a rare chromosome inversion, say, or else gaining the ability to use citrate required the accumulation of several mutations in sequence.

To find out which, Lenski turned to his freezer, where he had saved samples of each population every 500 generations. These allowed him to replay history from any starting point he chose, by reviving the bacteria and letting evolution "replay" again.

Would the same population evolve Cit+ again, he wondered, or would any of the 12 be equally likely to hit the jackpot?

Evidence of evolution
The replays showed that even when he looked at trillions of cells, only the original population re-evolved Cit+ ? and only when he started the replay from generation 20,000 or greater. Something, he concluded, must have happened around generation 20,000 that laid the groundwork for Cit+ to later evolve.

Lenski and his colleagues are now working to identify just what that earlier change was, and how it made the Cit+ mutation possible more than 10,000 generations later.

In the meantime, the experiment stands as proof that evolution does not always lead to the best possible outcome. Instead, a chance event can sometimes open evolutionary doors for one population that remain forever closed to other populations with different histories.

Lenski's experiment is also yet another poke in the eye for anti-evolutionists, notes Jerry Coyne, an evolutionary biologist at the University of Chicago. "The thing I like most is it says you can get these complex traits evolving by a combination of unlikely events," he says. "That's just what creationists say can't happen."
Click to expand...
 
I agree with the OP, but then again, who wouldn't?
 
hey piggy i think you destroyed the time space continuum.


there are two identical threads with the same replies but some missing.... no wait different...aaaaaaaaaaaaaaa
 
This thread, like the bacteria, has split into two..... it's multiplying.... destroy it, DESTROY IT NOW!
 
religious antievolution: but the fact is....is.....that the bacterias dont even exists! they are made by people to reduce the faith on god!,using those new computer graphics thing and such,you know how avanced science is!
 
oh god that is amazing. Of course creationists still won't believe it anyway
 
But, evolution is just a theory.

*BAMF*

Ow!
 
creationists won't accept evolution unless they see a bacterium turn into a monkey.
 
Okay that's fine, just tell me who next.
 
I that really never debate at we further of against who that doesn't. Very that change become for many generations, though groundwork obviously.
 
No more double posting please...you know the score.

Amazing story and research, I'm eager to find out what caused that change and what catalyses/ triggers it. I'd love it to be extremely concrete too, so we don't have to deal with creationism much longer.
 
<RJMC> said:
religious antievolution: but the fact is....is.....that the bacterias dont even exists! they are made by people to reduce the faith on god!,using those new computer graphics thing and such,you know how avanced science is!
Click to expand...

Religious anti-evolution: So...So... you proved evolution, eh?...well....well, how do you know God used his power to make the bacteria go that way?! Huh?!? Do you have an explanation for that one, Mr. Bill Nye the Science Guy?!
 
Leto said:
Religious anti-evolution: So...So... you proved evolution, eh?...well....well, how do you know God used his power to make the bacteria go that way?! Huh?!? Do you have an explanation for that one, Mr. Bill Nye the Science Guy?!
Click to expand...

Bill, Bill Bill Bill....

But now that this thread is srs bsns, I will admit that I am fascinated by this discovery.
 
Slug Advisor said:
Bill, Bill Bill Bill....

But now that this thread is srs bsns, I will admit that I am fascinated by this discovery.
Click to expand...

Tbh, I wasn't quite sure what the thread was about before...

But yes, I agree it's quite Cool. Although I won't be excited until they start mutating eyes.
 
Hey pig, yeah you.
Hey pig piggy pig pig pig!
All of my evolutionary traits came through!

Cool.
 
Science Infinity, Intelligent Design Ze-ro!
 
It made sense when there were two posts, but Grizzly deleted the second one.
 
Hectic Glenn said:
No more double posting please...you know the score.

Amazing story and research, I'm eager to find out what caused that change and what catalyses/ triggers it. I'd love it to be extremely concrete too, so we don't have to deal with creationism much longer.
Click to expand...
As if the current evidence wasnt concrete enough?? I suppose you've not talked to enough creationists to realise that even when presented with overwhelming amounts of evidence their typical reaction is akin to a child sticking both fingers in their ears and singing 'neer nerr laaa deeer I CANT HEAR YOU ner naaaaa neerrrr I STILL CANT HEAR WHAT YOU SAID blaaah bleeer daaaah' Just take a look at the youtube joke that is VenomfangX...
 
[Matt] said:
As if the current evidence wasnt concrete enough?? I suppose you've not talked to enough creationists to realise that even when presented with overwhelming amounts of evidence their typical reaction is akin to a child sticking both fingers in their ears and singing 'neer nerr laaa deeer I CANT HEAR YOU ner naaaaa neerrrr I STILL CANT HEAR WHAT YOU SAID blaaah bleeer daaaah' Just take a look at the youtube joke that is VenomfangX...
Click to expand...
Exactly. They don't even recognize transitional fossils.
 
Polaris said:
Exactly. They don't even recognize transitional fossils.
Click to expand...
The best evidence for me in terms of our own evolutionary background that shows common ancestry comes from our DNA in the form of endogenous retrovirus reverse transcription... Now we know creationists dont like learning as any form of thinking sends their brain into meltdown so the next time you bump into a creationist online just shove this easy to understand youtube video in their face...

http://uk.youtube.com/watch?v=TUxLR9hdorI

Having said that just read the comments under the video and weep... :(
 
God-botherers will say "what was the chance element? God, clearly."
 
newbitmapimage9bi9.gif
 
You must log in or register to reply here.

Similar threads

Bad^Hat
Scientists achieve technological singularity, ushering in a new age of peace and prosperity
Replies
17
Views
3K
DevonWC
DevonWC
CptStern
Only one republican candidate for President believes in Evolution
2
Replies
54
Views
6K
Sulkdodds
Sulkdodds
Warped
Humans affect the evolution of birds!
Replies
12
Views
2K
VirusType2
VirusType2
Krynn72
Dude strapped bazookas on a 700lb airplane and blew up tanks in WWII
2
Replies
40
Views
4K
Tagaziel
Tagaziel
No Limit
AIDS cured?
Replies
19
Views
933
Kula Meenur
Kula Meenur
Back
Top