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High Speed Evolution
Taco Cowboy writes: Normally, the term "evolution" implicitly refers to super-long time frames. However, in the case of lizards on Florida islands, evolution seems to have shifted into a higher gear. Researchers have documented noticeable changes in a native species over a period of just 15 years, after an invading species altered their behavior (abstract). "After contact with the invasive species, the native lizards began perching higher in trees, and, generation after generation, their feet evolved to become better at gripping the thinner, smoother branches found higher up. The change occurred at an astonishing pace: Within a few months, native lizards had begun shifting to higher perches, and over the course of 15 years and 20 generations, their toe pads had become larger, with more sticky scales on their feet.
'We did predict that we'd see a change, but the degree and quickness with which they evolved was surprising,' said Yoel Stuart, a postdoctoral researcher in the Department of Integrative Biology at The University of Texas at Austin and lead author of the study... 'To put this shift in perspective, if human height were evolving as fast as these lizards' toes, the height of an average American man would increase from about 5 foot 9 inches today to about 6 foot 4 inches within 20 generations — an increase that would make the average U.S. male the height of an NBA shooting guard,' said Stuart."
'We did predict that we'd see a change, but the degree and quickness with which they evolved was surprising,' said Yoel Stuart, a postdoctoral researcher in the Department of Integrative Biology at The University of Texas at Austin and lead author of the study... 'To put this shift in perspective, if human height were evolving as fast as these lizards' toes, the height of an average American man would increase from about 5 foot 9 inches today to about 6 foot 4 inches within 20 generations — an increase that would make the average U.S. male the height of an NBA shooting guard,' said Stuart."
ooo ooo ooo frosty piss!
the height of an average American man would increase from about 5 foot 9 inches today to about 6 foot 4 inches within 20 generations — an increase that would make the average U.S. male the height of an NBA shooting guard,
Is that unreasonable? If there were evolutionary pressure (ie, short people kept being killed before reproducing), and tall people got multiple mates, I could see this change happening within twenty generations. Twenty generations is enough for two people to repopulate large countries, or even the entire earth if they have large families.
"First they came for the slanderers and i said nothing."
I'm not sure that's so shocking. Assume there were a predator that killed 90% of the shortest 1/3rd of all humans at age 15. Let that run for 20 generations. I don't see how the average male height going to 6' 4" would be at all out of character. Heck it might happen faster than 20 generations, possibly more like 5.
If it happens fast, it's evolution.
If it happens slowly, it's evolution.
If it happens due to selection pressure, it's evolution.
If it happens without selection pressure (i.e. genetic drift), it's evolution.
So, basically, if reproduction occurs in there somewhere, it's evolution.
I'd really like to see a falsifiable rendering of "evolution". It would make discussion so much easier.
~ Whence do you come, slayer of men, or where are you going, conqueror of space?
Normally, the term "evolution" implicitly refers to super-long time frames.
Ummm, no it doesn't. Fruit flies, bateria, viruses and a host of other living things evlove on timescales that are observable by humans in near real-time. Taco Cowboy better stick to something other than commenting on biological processes that he knows little about.
So we have smart people who can write papers that sound intelligent.
This is not evolution. This is the same argument that Jean-Baptiste Lamarck put forward for inheritance of acquired characteristics.
I agree the lizards are hanging out higher in the trees(nice thing about the brain), the bigger feet thing is just because they use their feet differently.
If there is real evolution, then we will end up with a new species. This is just adaption on a human scale(maybe). Lets see if in 10k years if these lizards
can mate with their other relatives and produce viable offspring.
Fine, bring on the "redundant" mods.
jeffb (2.718), typing more slowly than Anonymous Cowards since 2008 or so...
The "ring species" are basically speciation events in progress. All it takes is one catastrophe, a disease or volcanic eruption or an invasive predator species introduction, that interrupts one of the breeding in one of the islands, and there will be two species. And this is what most anti-evolution folks don't get. No, a chimpanzee did not suddenly gave birth to a human. Population of the ancestor species split into two, and one evolved to become human and the other became chimpanzee. And the split need not be geographic. Changes in mate preferences, internal body temperature, food preferences, etc can lead to breeding isolation that could lead to speciation.
Still it is nice to see evidence being presented in a species much higher than mosquitoes.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Well, yeah, that'd work.
That's what "evolutionary pressure" is in the real world.
The change occurred at an astonishing pace: Within a few months, native lizards had begun shifting to higher perches, and over the course of 15 years and 20 generations, their toe pads had become larger, with more sticky scales on their feet.
This language confuses most non scientists and those not used to reading about evolution. The lizards did not convene a Supreme Soviet of Lizards and pass a resolution to shift to higher perches. The did not look at the evidence, pros and cons and decide, "yeah! sticky scales on the feet are a good idea. But Lizz Ard patented it. The survival of the species depends on it. So let us use eminent domain and make it public domain". Some lizards naturally like perching higher and other prefers perching lower and most do exactly what their parents did. The ones who liked higher perches survived more than the others, and their percentage in the population rose. Eventually only those who perched higher would be left alive.
The inuit are able to eat fried whale meat fried in blubber nonchalantly because those who could not handle that much cholesterol died out ages ago. Lactose intolerant toddlers died out en mass some 8000 years ago in western europe. That is why humans should try to stick their "ethnic ancestor" foods. [begin personal rant] Indian Indians (not American Indians) went through so many cycles of feast and famine. Only those who had the ability store fat in the times of plenty survived the lean times. When they get F-1 visa, then green card then citizenship and melt into the melting pot guzzling beer, eating pizza, their genomes are still gearing up for the next famine that could be just round the corner. Heart disease and diabetes is rampant among the immigrants from historically impoverished ethnic groups are very very susceptible to diseases of the plenty. Your body evolved to eat what your grandpa and his grandpa ate. If they eschewed bacon, stay clear of bacon. If they ate rice and lentils and ate samosa and jamoons only on festival feasts, you would do well to do the same. Stop ordering dessert in every meal and pigging out in the 9$ lunch buffet with unlimited mango lassi at India Palace. [end rant]
It is fascinating to see it from evolutionary perspective. But evolution has been used by every one with a perverse agenda to justify their ulterior motives most scientists steer well clear of explaining it in simple terms. They hide it in obscurantist journal papers with very dry commentary.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
I don't know why the researchers were so surprised by this. If the genetic variation already exists within the population under selective pressure, then the "evolution" measured by phenotypical changes in the population can take place literally overnight. Kill every human under 6'4" and the population will be 6'4" from then on, especially if you don't return to the set of selective pressures that had encouraged the shorter average. Sure there will be a lot of shorter individuals being born at first, but they'll fall to the same new selective pressure that killed the initial short cohort. This is exactly how the famous peppered moth evolution event happened so quickly; it wasn't anything unusual about the moth species in question, just a quick change in the suitability of existing genes. Evolution is only slow when the locally optimal genes don't exist in the population, and need to arise by mutation or genetic flow, or when an immediate optimum has room for genetic fine tuning, so to speak. TFA isn't really an example of evolution per se, it's an example of natural selection--a closely related concept in that they almost always co-occur, but it is not the same thing. We've changed the equilibrium frequencies of various genes, but as far as we know there are no new genes in this population. (And as far as that goes, it's a decent illustration of the importance of genetic diversity in a population: this population would be extirpated if it didn't have the genes responsible for these behavior and phenotype changes.)
How long is one human generation?
The important part is that we are NOT seeing such rapid changes amongst the PREDATOR population. So this is not unusual at all.
The lizards that are not sticky enough to climb out of reach of the predators are the lizards that get eaten by the predators.
We see this on the farm. Nature guides the hand of evolution in the wild through selective adaptive pressures. On the farm it is the hand of man, sometimes, but the same thing. We use selective pressure to improve our livestock. In just the past slightly more than a decade we have made significant evolutionary changes to our pigs. They're a particularly nice animal to work with for genetic selection because they reproduce fast (up to 3 litters a year) with very large litters (8 to 21 piglets per litter) with rapid growth (6 months to market, 9 months to breed) so we can turn over generations quickly.
Consider dogs (all breeds derived from wolves several thousand years ago) and foxes http://cbsu.tc.cornell.edu/ccgr/behaviour/Index.htm the genetic basis has been studied and similar studies have been done on other domestic animals. The chicken http://en.wikipedia.org/wiki/Junglefowl This type of "evolution" is really just exploitation of existing genetic variation within a species.
Only GOD can act so quickly to act against our Sin. It is in Him that we can look for an answer, always.
Man Sins and goes against His work, and so He must protect His creations by giving them better adaptations. There is no debate about this. Science cannot explain it, because science is an imperfect creation of Man and a direct affront to His image.
Nothing really new here.
Wolves, then seen as unreservedly undesirable, were eradicated from the Yellowstone region by the early 20th century. Between then and the end of the century, coyotes got larger and started hunting in packs, taking the ecological niche that wolves had filled and pursuing larger prey.
Then (1994) we reintroduced wolves to Yellowstone.
Even in the short time since, observed coyotes have gotten smaller and started acting less like apex predators and more like the sneak and scavengers that they are in other habitats where they're threatened by the apex predators.
That's a lot fewer generations than the reported adaptation of lizards in the islands.
Lacking <sarcasm> tags,
Anyone who's ever lived in a Victorian-era house can do better than this.
In the last hundred years, doors that were perfectly shaped to allow entry now have their upper limit at eye-height. You literally cannot walk into an old house without ducking all the time.
And that's just a couple of hundred years, a handful of generations.
Sure it might be something other than "environmental" factors, but it's telling you that species can change extraordinarily rapidly given the right conditions.
That is all.
"If any question why we died, Tell them because our fathers lied."
I didn't know of the subway mosquitoes speciation event. The mosquito is known as "London underground mosquito", but is present in New York subway and sewers too. The relevant wikipedia page is not particularly well written but has interesting resources none the less:
http://en.wikipedia.org/wiki/L...
Funny. In the last 100 years, human height has gone from an average 4'11 to what it is now, 5'9"
This can be determined by visiting existing structures which have stood for some great deal of time - such as old west towns in Arizona and evaluating photos of people back then in contrast to existing structures and seeing the remarkable height difference.
Interestingly, this is not documented as such.
The same thing has been occurring across the board for different species.
South Florida has an amazing invasion of exotic lizards of several species. They are thriving and increasing in number and variety. Iguanas are common place here and it is more than one type of iguana at that. We have moniror lizards as well as species that I do not know the name. One iguana that I am seeing has a bright orange head when small. Pythons are also getting really common and we have had one cable guy bitten by a green mamba. There are cobras caught on rare occasions as well.
Much of that height difference is probably due to better diet and healthcare, and not evolution. For example, N. Koreans are noticeably shorter than S. Koreans due to diet, medical, etc. despite being recently separated.
Table-ized A.I.
It is super easy for drastic evolutionary changes to occur rapidly, and such changes could occur in less than a day. The key to remember is that various definitions are commonplace for the word "evolution". For example, a common scientific meaning is a change in allele frequency. This may occur due to the generation of novel alleles or natural selection acting to change the frequency distribution of existing alleles. A common layman definition of evolution is the generation of novel DNA or a novel physiological trait.
There is little speed limit to the rate at which natural selection can act on an existing population. However, the generation of new alleles is limited by the laws of probability and the current population size and generation time. The article gives no indication that it was about novel alleles, therefore I assume that it is about the well-known fact that natural selection can act quickly.
Don't waste your vote! Vote for whoever you want, unless you live in a swing state it won't matter anyways
Same thing is happening among the cane toads spreading from one side of Austrailia to the other. The fastest ones on the frontier only mate with each other, making super fast cane toads.
This selection is only within existing genetic variation. Evolution requires mutation as well. As commented elsewhere, if you sterilize everyone with black hear, everyone will be blond in a generation. That is not evolution.
don't cut it off www.mgmbill.org
Wolves - dogs are a particularly interesting one.
They have been domesticated many times in many places. Or one might argue that they have domesticated humans many times in many places.
Similarities between wolf and human culture led us to work together. As a group we are more powerful working together than either is apart. The wolves and humans who learned to work with their opposite comspeciest are the most powerful.
Together we were able to domesticate other animals for meat. Wolves kept browsers out of human gardens. Humans shared food and fire. A very good bond.
Evidence varies from about 11,000 to 40,000 to 60,000 to over 140,000 years ago that our species started working together. Very strong evidence that we met up and retained multiple times.
What we like most about you is that you have thumbs and your minimal fur doesn't catch on fire. Very handy.
-Sire Grey Muzzle, 8109 PD
evolution = variation + selection
What's happening here is likely more about selection then variation, although maybe a bit of both. I suspect this is largely the mechanics of punctuated equilibrium at work.
The way evolution is taught at high school level is typically over simplified to the point of being wrong, as indeed are many subjects. Evolution is NOT a continuous process of each generation getting better fitted to the environment via the process of natural selection acting on genetic changes introduced in individuals in that generation...
The normal way that evolution is understood to play out in practice is via "punctuated equilibrium" whereby genetic changes - which are typically too small and/or irrelevant to have any immediate impact on fitness - accumulate in animal populations over many generations. It's not the genetics of individuals that are changing so much as the genetics of the interbreeding population as a whole as accumulated changes get spread throughout the population over a number of generations. This is the "equlibrium" phase whereby genetic changes are accumulating but there is no external evidence of this as the changes are irrelevant to fitness.
What happens next is the "punctuated" part of "punctuated equilibrium" - something changes in the external environment that the animals are part of - in this case the arrival of an invasive species. These changes in the environment (drought, disease, invasive species, etc, etc) can happen very quickly compared to the speed at which genetic change accumulates. Now, it may happen that in the new changed environment some of the accumulated genetic changes that were previously benign now become a factor in fitness (either positively or negatively) and therefore a "sudden" change in the population may be seen as those individuals possessing what has now become a helpful trait, or not posessing a negative trait, prosper relative to their peers and rapidly come to dominate the population.
When a change in the environment brings about a quick change in an animal species, it is tempting - but sloppy - to say they are rapidly evolving. What happened rapidly was the change in the environment, not the slow process of genetic change that suddenly became significant.
In this case the Florida lizard population presumably already had all the traits - to some degree - that would prove positive or negative when the invading Cuban species arrived, and a quick change was seen as natural selection did it's thing and over a few generations the population became dominated by individuals having the (slowly come by) traits that now proved to be critical.
Of course there's more to how the dynamics of evolution play out than just puncuated equilibrium... While it's always going to take a long time for any complex feature such as sticky toes (or toes themselves for that matter) to evolve, the way genetic coding works is such that it may be very easy for a feature - once it exists - to be modified by a small change (e,g. a birth defect giving you unwanted extra limbs or extra sticky toes - advantageous if you mostly climb slippery trees, disadvantageous if you don't).
So.. the big picture here is that the Florida lizard species will have already accumulated the feature set that proved advantageous (or disadvantagous for those that dies giving way to the "new" variety), and this just played out once the environment changed. Subsequent to the changed environment additional variation/selection (which you could think of as optimization "tweaking") of the most critical features (toe pad size, scale stickyness) may have occurred.
Looks like their habitat just got a period. Or at least a comma. Vroom!
There's no time like the present. Well, the past used to be.
The GEICO gecko evolved speech with a strange pseudo-Brit accent in just about that length of time. I hear he is mated to a female, Elizardbreath. But he has a reptile disfunction...
Wow, its sad how many people still have faith in evolution...
Not evolution.
Article is not titled properly.