"The speed of evolution" Topic

link

Perhaps, evolution happens faster then first thought.

30 years means a lot of lizard generations. Even if the lizards just bred once a year that's a lot of generations in a new environment. If they breed twice a year, that's 60 generations in a new environment. Thye may have also interbred with the indigenous lizards to some degree, although that's unlikely. Only humans are willing to mate with anything that looks remotely like a human, other species are far more discerning.

I'm reminded of the chart we had in my college physical anthropological class that showed long periods of slow evolution interrupted by short bursts of rapid evolution, labeled "adaptive radiation." Of course, the chart also showed Piltdown Man.
Grelber
Who is feeling rather old now, thank you.

Run IDers Run!! j/k

WOW! is freaking right! That is impressive.

Read the thing properly.

Firstly, it specifies "30 lizard generations".

Secondly, the changes are not necessarily evolution. A people who spend a lot of time outside are browner than people who do not -- without any evolutionary change. People nowadays are much taller than people 30 generations back -- but not thanks to evolving quickly.

"All of this might be evolution," Hendry said

Evolution, even when it does occur is highly dependent on the direction of change. One cannot assert because some changes occur fast that all evolution works that way. (For example, pygmy forms are known to evolve quickly, and many colourations alter fast. But that says nothing about other changes.)

I bet it's all just a reporter getting the wrong end of a science story. Happens all the time, sadly. (Not helped by the odd deluded scientist.)

Wow, those lizards are pretty darn smart to do all of that in 30 years! Not nearly as smart as those bats who learned to use sonar, of course.

In the 40's and 50's, the Soviets were trying to breed foxes that were more easily breed in captivity. They took the foxes that did not exhibit flight or fight characteristics. Apparently when you start breeding for this characteristic, it is linked to all kinds of other characteristics. The foxes fur became dappled, their muzzles became broader and the foxes started to bark. Here is a link,
link

In this case, the lizards developed an entirely new set of digestive sphincter muscles and a stronger jaw musculature. That's a little more change than just pygmy-izing or coloration change.

Of course it's possible that they were just re-asserting characteristics that had been "de-volved" by their ancestors.

Not exactly a sound scientific experiment. It reminds me of an example given by my science teacher in grade school discussing the scientific method. I forget who the 'scientist' was, but sometime in the 1600s he put a horse hair in a puddle of rain water, came back the next day and saw a worm in the puddle. His conclusion was that horse hairs would turn into worms if left in rain water over night and that's how the world got worms. Brilliant!

That's how you make dog breeds, isn't it?

"Punctuated equilibrium".

-Kle.

Exactly what Kle says. Evolution can occur very rapidly when an organism's environment is changed abruptly is was the case here. Actually, we are constantly evolving.

The story looks at thirty generations of those lizards. If you looked back 30 human generations (approx. 750 yrs) you would see humans that had some pretty significant differences too. For one, it's a good bet that none of us would survive more than a few weeks in the 13th century. Our modern creature comforts, such as potable water, processed food, and of course medicines have allowed humans in many areas of the world to evolve into a species that is less resistant to disease and physical hardships.

Still 30 generations for a such a dramatic change in physiology, as seen in those lzards, is pretty interesting.

Mark Plant wrote:
"Secondly, the changes are not necessarily evolution. A people who spend a lot of time outside are browner than people who do not -- without any evolutionary change. People nowadays are much taller than people 30 generations back -- but not thanks to evolving quickly."

A good point – and it brings up something that I was reading about last year. There is a hypothesis starting to be kicked around that evolution may proceed something like this:

a. species exists in some environment, has a certain 'plasticity' about it that allows it to change physically without necessarily changing genetically (similar to the ability to tan when exposed to the sun).

b. species' environment changes, due to emigration or climate change; individuals in the species that can change enough to survive the new environment do, and over the short term the species evolves 'physically'.

c. over time, as survivors produce offspring, genetic changes that make it easier to meet the new environmental conditions cause a genetic evolution that codifies the modifications needed to survive the environment. evolutionary adaptation to the new environment is complete.

In other words, what has happened in only 30 generations of lizards may be step b of the process, while step c may or may have occurred significantly. Hence the last line of the article mentioning the next step – to confirm the genetic basis of the changes.

Ultra Ork wrote:
"Not exactly a sound scientific experiment. It reminds me of an example given by my science teacher in grade school discussing the scientific method. I forget who the 'scientist' was, but sometime in the 1600s he put a horse hair in a puddle of rain water, came back the next day and saw a worm in the puddle. His conclusion was that horse hairs would turn into worms if left in rain water over night and that's how the world got worms."

It certainly isn't how you'd plan it from the start, but it does have the hallmarks of a good experiment – namely, there are two conditions (lizard in original environment vs. lizard in new environment) with one specific change between them. So long as the researchers focus on comparing the new island lizard to its original island progenitors, they should be able to draw valid conclusions. Note that they already confirmed that the lizards they found after 30 years are the genetic offspring of the 10 founders – so we know that we aren't looking at a worm that is unrelated to the horse hair we dropped yesterday.

And to Number 6 – thanks for the link, this is definitely going into my evolution lessons next year! (I teach biology in high school…)

lugal hdan 22 Apr 2008 6:44 a.m. PST
In this case, the lizards developed an entirely new set of digestive sphincter muscles and a stronger jaw musculature. That's a little more change than just pygmy-izing or coloration change.

Interesting, why should any particualr genetic change be more complicated than any other?

Of course it's possible that they were just re-asserting characteristics that had been "de-volved" by their ancestors.

Good point. Like teeth in chickens, or the human tail.

Hi

These aren't "evolution", they aren't new speies of lizard, they have in genetic drift selected a few exterior appearene changes. As in Aussie Aboriginies, Pygmyes and Inuit look very different, have very different phenotypes, react very differently to heat and cold, but are still the same species.

Or to illustrate, A couple road trips ago, I saw a "dog" that was clearly half "chihuaua" and half coyote. The run the same range, can interbreed with viable offspring, therefore the appearant differeces are just appearance.

They don't say if lizard is a 'mix breed' or not. Also, sounds much more than just their appearance has changed as well.

Hi

My point is that while there are detail differences between coyotes and dogs that, essentially, they haven't evolved. just breeds. In the case of the coyote, he RUNS and walks differently than any dog. This half breed ran like a coyote, but had that intrinsic "love human" that we bread them for.

Or why your kids don't look like mine, or sound the same and have diffeent skill sets. Or how I don't respond to any amount of caffeen.

R

R

Interesting, why should any particualr genetic change be more complicated than any other?

I'm guessing it could be that pigmy-sizing and coloration are determined by fewer genes than the other traits, and/or that a slight genetic change can therefore have more dramatic results.

Hey Rocky, those examples actually are evolution. Evolution is change. It doesn't have to be big or small, or better or worse. It's just change. You don't necessarily have to have a new species, though evolution often leads to that.

For example. The average person today probably has worse eyesight than the average person five to six hundred years ago. One reason is that eyeglasses have allowed contemporary people with bad eyesight to survive and procreate as efficiently as their perfectly sighted human brethren. As a result, the genetic coding for poor eyesight is not weeded out of the genepool as completely now as it was back then.

I think your coyote/chihuahua mix anecdote is a very good example of evolution.

Yep, sounds pretty evolutionary. At the moment the distance between the two populations isn't that great so they may be able to successfully interbreed to produce offspring that themselves can breed [see the whole horse – donkey breeding thing in many textbooks].

Given further isolation, continuing modification in either population could make interbreeding impossible – eg evolving a different penis shape, changed courtship rituals [ask any <40 year old how well your best 80s disco moves are going to work]or a myriad of internal or chromosomal changes that may take place in response to the different environments etc.

30 years / ?30 generations seems really fast, but if the normal food sources weren't present then there may have been a really strong selection towards specific, very minor beneficial differences between individuals. The key thing is that they take effect before or during the breeding life, so there is some impact on inheritance [see disco clothing in wardrobe – waiting for the day its back in fashion and a new generation of Small Slightly Naughty Banksiamen to be propagated].