A Toxic Cane Toad: Super-quick evolution has allowed the cane toad, above, to invade Australia at a rate of 30 miles per year today, compared with seven miles per year in the 1950s.
Posted on 02/15/2006 1:30:20 PM PST by PatrickHenry
Fat, toxic toads at the leading edge of an Australian invasion have evolved longer legs than those behind the front lines, report biologists.
The alarming discovery not only means the toads can spread more quickly over the continent, but it raises the possibility that under the right conditions, animal evolution can happen in just decades, not eons.
That, in turn, has major implications for animals adapting to global warming, as well as biological pest control projects, which generally take for granted that carefully studied animals introduced to fight off invasive species can not evolve into something troublesome.
The inexorable, seven-decade-long expansion of cane toads from their disastrous introduction to Queensland in 1935 has long been monitored by biologists.
One such biologist was recently driving along a toad-crowded road one night, along the invasion front about 40 miles east of Darwin, when he noticed how desperately the toads were hopping grimly toward him, all facing the same way: into virgin territory.
"It was just like an invasion in a science fiction movie," said biologist Richard Shine of the University of Sydney.
Shine is a snake specialist, but when the toads began heading toward his study area, he decided it would be wise to "know thine enemy" before they arrived, he explained.
So for years Shine and his colleagues have been tracking cane toads, and as a matter of course they weigh the toads and measure them. Those records came in handy when they discovered that some cane toads at the invasion front were covering an unprecedented mile-and-a-quarter (two kilometers) each night.
"Sure enough, there was a pattern," said Shine of their astonishing leg-length discovery.
Not only were the legs of pioneer toads significantly longer, but the same athletic build dies out among toads as areas become more settled.
In other words, there appears to be a great advantage to getting the first crack at virgin territory. That boils down to the opportunity to produce more viable tadpoles that grow up to continue the line. For seven decades now that advantage has been awarded to cane toads with the longest legs. That has lead to the steady breeding of longer and longer-legged toads that can keep beating the crowd.
The disheartening result is that the toad invasion rate has increased from seven miles per year in the 1950s to a whopping 30 miles per year today, report Shine and his colleagues in the Feb. 16 edition of Nature.
The silver lining is that the cane toads are showing how quickly some species can adapt to new environments, a challenge now facing innumerable species worldwide as the global climate warms, said ecologist and rapid evolution researcher David Skelly of Yale University.
"We never think of evolutionary changes happening that fast," said Skelly of his fellow ecologists.
That has to change, because the cane toads are just a high profile case of something that is being seen in many organisms all over the planet, he said.
"It doesn't mean that we have no problem (with climate change) or that all species will be viable," said Skelly. But there is evidence that many species might be more able to adapt than previously believed.
Another place where people have to start thinking about rapid evolution is at the federal and state agencies where they evaluate exotic species for release as biological checks on exotic pests, said Skelly.
Right now those agencies don't consider the possibility that a new exotic species will very likely change in its new environment, for better or worse. It's time they started thinking differently, he said.
There is also debate among meteorologists about what effect the increased temperature would have. It's possible that it could result in increased cloud cover, which would reflect back more of the incoming solar radiation, which would then mean cooling. There are way to many variables.
The problem is climate change takes place over long periods of time. The year to year variations cannot determine a pattern.
In a nutshell, no one knows what's going to happen. What if we get another Krakatoa type volcanic eruption? All the human efforts to steady the climate would be wasted.
Mine.
Never thought of it that way. Thanks!
Personally, I think more serious work is done by those who take an Irish Breakfast, especially compared to those who indulge in cognac soirees.
This is not a scientific context, and there're precious few scientists involved in this online discussion forum--what scientists I have known are not bossy, obsessive internet nags carrying water for a sneaky, cowardly overlord.
You can carp and squawk and be condescending, but you're still the equal of any other freeper and can't force others to bow to terms that you'd like to set. No white coat halos for evos.
Evos visit every evo thread, and keep posting spam, and keep annoying any who might be persuaded.
Why should we accept your terms, when you evos are incontinual bad faith on these discussion boards? You make a nuisance of yourselves to mods, you engage in endless tedious remarks like "you need to go back to biology class", coordinate your "two-minute gangups" where suddenly a group of evos will arrive at the same moment to post ad homs, insulting pictures of opponents, yeah, REAL science going on here--
Maybe you're out of work, but all this time you spend might be better used finding that tenured job of your dreams, when you can bully grad students instead of being an obsessive i-nag.
When regular folks see the word "evolution" they have some assuptions about it (and your spam lists better be broadcast a little farther than obsessive reposting here on a few poorly-attended FRevo threads)--they expect it to have something to do with new species, or the reasonable expectation of some speciation event.
Evos here on FR play rather fast and loose with the definition of Evolution. On one thread, it is assumed to connote speciation. On the next thread, an evo is in a rage because an opponent assumes that evolution has a connotation of speciation.
No Freeper should be surprised to see an evo "arguing" in bad faith.
Now the Asberger-Syndrom control freaks are trying to ENFORCE a list of definitions. I'd like to point out that no freeper is under obligation to pay the least attention to any lists--it's just a sympton of evo OC behavior and we should not be "enablers" to it.
That has somehow inherited the BARBIE gene!
Carolinagirleyman, You're what my coach used to call a "gutless wonder."
The only thing is what about reports about the ozone layer in South America and Australia? Is it just hype or is it really happening that humans are starting to need to use more sunscreen etc to adapt to more UV radiation?
http://www.recyclingpoint.com.sg/Articles/20Oct2000Life_under_the.htm
FReepmail me to be added or removed to the ECO-PING list!
ahh, the beauty of genetic variability!
"I was a toad yesterday. I'm a toad today. I'll probably still be a toad tomorrow. *SIGH* There really is little room for advancement in my field."
With apologies to "Snoopy" who says the same thing about being a dog. :)
I've read several articles that vitamin D is actually preventive against some kinds of cancers including skin cancer. This has caused a real dilemma for those who advocate lots of sunscreen. Here's the link to an article: http://www.msnbc.msn.com/id/7875140/ I imagine that if I lived there where there was little or no protection against UV from the ozone layer, I would be more careful, too. But up here in the north, I don't worry about it. Between the clouds and staying indoors for so much of the winter, I don't think we're exposed to enough during the rest of the year to worry about, but that's just my opinion.
The hole seems to be shrinking:
http://news.bbc.co.uk/2/hi/science/nature/1050495.stm
Note that they directly attribute this to the global ban on PCB's. If we start making these chemicals again, the effect will reverse.
"Oh, OK. I guess that means that faith in God is false."
You seem rather preoccupied with trying to set up a dichotomy between religion and evolution yourself, while condemning those on the opposite side of the debate for doing the same.
"What if they have advanced to their own destruction?"
Then their evolution wasn't quite so prescient after all.
" I'm a very tall fellow; am I more highly-evolved (or less-evolved) than my short fellow man?"
It all depends upon context, apparently.
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