Evolution can occur quickly and change how populations interact [Lab demonstration]

Cornell University ^ | 03 July 2006 | Susan Lang

[PatrickHenry]

Biologists generally accept that evolutionary change can take from decades to millennia, while ecological change can occur over mere days or seasons. However, a new Cornell study shows that evolution and ecology can operate on the same time scale.

When evolution occurs so quickly, the researchers conclude, it can change how populations of various species interact. Ecologists need to consider such evolutionary dynamics in their studies because evolution could affect populations being studied. This insight is critical to predicting the recovery time needed for threatened populations or for predicting disease dynamics, says Justin Meyer '04, who conducted the study as an undergraduate student with Cornell ecologists Stephen Ellner, Nelson Hairston and colleagues.

To observe ecological and evolutionary changes together, the researchers monitored the ecological fluctuations in a model predator-prey laboratory system: a microscopic organism called a rotifer that eats a single-celled algae.

Meyer developed a method to track genetic changes, and the researchers found that as the prey population fluctuated, the algae "evolved" from a type that grows quickly to a type that resists being eaten. The frequency of the algal-genotype changes in response to rotifer population flux clearly demonstrated the synchronicity of ecological and evolutionary time.

The study is published in the July 11 issue of Proceedings of the National Academy of Sciences.

[bvw]

Don't be ingesting the tin soldier picture please. It's one third lead. And no artificial sweetener gone awry at all.

[SaveUS]

"(bvw)Like the dinosaurs, however, death of a bad idea is a long time passing."

"So were dinosaurs an experiment?"

You know, if you think about it critically, humans may be the least favorable evolutionary model so far. Seems like a perfect path. An organism that can reflect on itself, develop way to heal itself, and possibly even escape its environment. Seems like a good pathway. The problem is it is a "hot" pathway that will probably burn itself out quickly in geologic terms. And, if you think about it, evolution doesn't seem to care so much for intelligence, especially self recognition type intelligence. It seems to be perfectly happy evolving bacteria. So, with no favoritism, and no care for time passed, evolution is truly a perpetual life engine.

[Stultis]

(the rest were eaten, of course)

Actually they were all eaten by the rotifers. The resistant strain was able, a greater percentage of the time, to pass through the rotifer undigested. (The evolutionary trade-off was that the resistant strain couldn't reproduce as fast as the others.)

[SaveUS]

"Don't be ingesting the tin soldier picture please."

Ok, I agree not to eat the tin soldier, and you agree not to bounce any bloated cats in any of the threads. lol

[ml1954]

You know, if you think about it critically, humans may be the least favorable evolutionary model so far.

Well, except for developing the ability to deliberately destroy itself, it's been successful so far (I think that's Sagan's point).

And, if you think about it, evolution doesn't seem to care so much for intelligence, especially self recognition type intelligence.

I think the jury is still out on that. AFAIK, there's no data to support your speculation.

[Stultis]

My conjecture is that the resistant algae existed in the population, and only came to the fore when it became obvious that the resistant ones were the only ones still undergoing mitosis

I don't know what the heck "mitosis" has to do with anything, but the researchers never claimed anything like what you're making a big show of refuting. I haven't seen the full article, but I read the abstract earlier today. They started with clones, I think two fast growing types and one digestion resistant type. There was never any claim that the types evolved during the experiment. The experiment started with them.

The point, if I understood what I read, was to track evolution (changes in population genotypes) in real time, and thereby prove that the rates and patterns of the evolution matched a mathematical model the experimenters had previously proposed.

[SaveUS]

"To see the real-world evolutionary importance of built-in biological mechanisms of genetic change, we have only to consider the post-WWII emergence of multiple antibiotic resistance in bacteria."

Makes you wonder how earlier life thrived with no knowledge and no ability to kill bacteria, yet man can lose millions of people with just one flu virus. And man has the ability to at least partially cure himself. Dinosaurs went millions of years, and had no intelligent ability to heal, and yet survived until wiped out by an outside source. It is almost like man is causing bacteria to "hurry" and find new pathways of survival. Which may actually lead to his demise.

[SaveUS]

"there's no data to support your speculation."

Yes, that is true. I was just throwing a thought out. It just seems that man has evolved the ability to self-destruct, which is probably a dead end road. But definitely not a scientific claim, just sort of a philosophical one.

[LogicWings]

I'm going to just jump in here and answer a few posts all at once. Sorry for the lapse in protocol but I'm lazy and have other stuff to do.

RobRoy:
If you have a part of the country that has a population made up equally of black bears and Polar bears, and one day the temperature drops substantially, and it stays that way for ten years, you will notice that there will be a lot more polar bears, and many less black bears. But nothing evolved, even if the black bears died out completely.

It's funny that you say that because Polar Bears are just white "adapted" Grizzly Bears. The broke off 200 million years or so ago. If you Google "Polar Bears Grizzly" you will find a recent case where they interbred in the wild. They have been doing this in zoos for a while and the offspring are fertile so the question is "Are they really separate species?" With fertile offspring the technical answer is no. So why are all the Eco-Nuts freaking out? (Silly question, because that is what they do.)

Same is true for dogs, wolves, coyotes and dingos. The Red Wolf is pretty much extinct due to interbreeding with coyotes. In Canada they stake in-heat females (usually German Shepards) out over-night so the wolf males will breed with them. All the offspring are fertile.

The Dingo is vanishing because domestic dogs that get lose and run wild are interbreeding with Dingos and slowly destroying the "species." But if all these different "species" freely interbreed are they really different species? Technically the answer is no.

The point is how far does a line have to "evolve" before it becomes a separate species? Horses and donkeys, and zebras and donkeys, and lions and tigers can all interbreed but the issue is sterile.

Now, imagine a Great Dane and a Chihuahua breeding in the wild. Impossible, but they are the same species, aren't they?

So how far would a Polar Bear have to evolve before it couldn't interbreed with its Grizzly ancestor? Ten more ice ages? 50? 100? Every warm period between ice ages thins their numbers down and they interbreed with Grizzlys, thus keeping the link alive. (And don't give me any of the Global Warming crap - we are between ice ages and the breakup of the Arctic Sea is the beginning of the next one, Go study the history of the Columbia Gorge. It's called a cycle.)

But nothing evolved, even if the black bears died out completely. Natural selection would simply have chosen the strongest of two EXISTING types, elimintating one. The diversity of the poplulation was reduced, not expanded.

You, like so many here, don't understand how evolution works. What if the Black Bears didn't die out completely but just a few hundred survived? What trait would they have in common that furthered their survival? Thicker blood, more fat, longer hibernation periods, longer gestation, larger size. Repeat this process 100 times over 1 million years. Now you have a Black Bear that is bigger than a Grizzly and can hibernate for half a year comfortably. It could no longer breed with the Black Bear it decended from. It would, at that point, be a "different" species.

The problem is in having a "static" view of reality as opposed to a dynamic one. The former is locked into concrete bound "everything" is a "thing" view and the latter allows for the understanding of abstractions and processes.

To give you an example. What is "cause and effect?" Hand me one, point one out to me. Can't be done. It is a complex abstraction that requires complex thought. That doesn't mean it doesn't exist. Evolution is cause and effect as it pertains to life. That's all.

Old Professer:
How, exactly does algae resist being eaten, I wonder...

By making itself very untasty, like the Monarch butterfly. Or by becoming poisonous like penicillin. Just one lucky toss of the genes and nobody wants to eat you anymore.

Mineral Man:
Learning fast you are.

Very funny that is.

[bvw]

When I was a young and curious lad living on the edge of swampy woodlot I was fascinated by the decay process of small dead animals that one comes across, yet as an adult I find the process disgusting to come upon in a walk and avoid the by distance and redirection of gaze the ocassioned fetid carcass. Yet I still "enjoy" -- find a fascination in -- written forensic descriptions of the process. Fwtw.

[furball4paws]

I have often said that man has interfered with his own evolution with the implication that he better be successful in engineering a better human or he will get extinct pronto.

[SaveUS]

Evolution is science.
Religion is faith.
I just see two totally separate paths here. But I do respect your post, and your thoughts. Things can be looked at many ways.

[SaveUS]

"he better be successful in engineering a better human or he will get extinct pronto."

Yeah, it is as if man is just the stimulant that helps bacteria evolve. It seems there are so many things that could possibly wipe us out, and many of those we created. I wonder how long it would have taken bacteria to get to the resistant stage some of it is at now, if man didn't poke at it and stimulate change? So, in the long run, maybe man would have been better off not trying to find ways to combat it. Who knows, its late. I'm going to dream of dead bloated cats, and hope Timothy Leary isn't in one of them.

[SaveUS]

I was fascinated by the decay process of small dead animals that one comes across,"

What the heck? Well, that did remind me....
The one thing I'll never forget is coming across a dead cow in the woods while hunting. A friend of mine and I stopped and looked around it to see if we could tell what had happened, and it started moving. Not much, just slightly shaking. My friend put his boot on its hind quarter and gave it a nudge, and it started moving a little more. Then, a Opposum(sp?) came crawling out from inside of that dead cow. We grossed out, laughed, gagged, all the way back to camp. Nasty.

[Stultis]

Pigeons. It's amazing how adaptable they are - and are yet one species...

No. There are many species of pigeons and doves. A little over 300 IIRC, although only one species was domesticated, several thousand years ago. There are several dozen species just in the Genus to which the domestic pigeon, Columba livia, belongs. (The terms "pigeon" and "dove" are effectively interchangeable. The smaller species in the pigeon family are more apt to be called "doves".)

I'll assume when you say pigeons are "one species" you mean to refer to the fact that the domestic pigeon, including it's various and wildly varying breeds; the wild rock pigeon; and the feral pigeon (wild domestic pigeons like you find living in cities, which are somewhat different from, and more various in plumage and behavior than, the pure wild Rock Pigeon) are all the same species. This much (I *think*) is true.

And the funny thing is... no matter how "far out" the breeding went, subsequent generations always returned to the archetype.

Um, no. I don't *think* this is true. First of all feral pigeons never (quite) return to the full form of the true wild Rock Pigeon. The later exists in pure form almost exclusively in remote regions.

I'm almost certain that the "always" is false. I'd bet many of the well established breeds, e.g. carrier pigeons (not to be confused with homing pigeons, but rather the breed with the wattles around its beak and eyes, and the unusual tall and upright stance), breed true to form over however many generations.

Rock Pigeon (This looks like either a wild one or a feral resembling the wild type. Feral pigeons come in many other color patterns as well.)

Carrier Pigeon

[Stultis]

And yes, actually, threads in the Religion forum have attracted frevolutionist scoffers.

None of the better class of FRevolutionist scoffers go there. Must be the scum of the scoffers.

[Coyoteman]

And yes, actually, threads in the Religion forum have attracted frevolutionist scoffers.

None of the better class of FRevolutionist scoffers go there. Must be the scum of the scoffers.

Or it might be a thread that was moved to the Religion forum, as has happened recently. (As I recall it was subsequently sent to the SBR.)

I don't think its polite to go to the Religion forum and bash anything.

And I wish some of those folks would just leave the serious science threads alone. Just because they don't like science is no reason to poison the threads. We have had a lot of threads dumped into Chat or the SBR because of deliberate trolling.

[Ben Chad]

Man plays God over a petri dish. A higher intelligence might be "playing God" with the "petri dish" that encompasses our world. A higher intelligence than that might be "playing God" at the galaxie level. There could be Gods reigning over dimensions or other universes we can't see. If I get struck by lightening today, you'll know I was on a hot trail of thought.

[HayekRocks]

Thank you for the explanation. It is a hugh relief to know that you realize that the idea all variation in a population was pre-existing is not feasible. I was afraid you were series.