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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."
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."
Discussion?
Evolution is easy to falsify. Apply pressure and see if the species DOES NOT adapt to the pressure.
If you believe that genes exist, then you believe in evolution, it's that simple. And if you don't believe that genes exist, then you might as well not believe in medicine either, or believe that cell phones exist, because it's all the same science.
If you kill the shortest third of all humans, the average height goes up immediately within the current generation.
If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
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
The average height of post-war (WWII) Japanese was 2 inches taller than the previous generation. and that was due merely to the better availability of food--an environmental factor--but probably not anything to do with evolution per se.
As stated in another post, if you kill off the shortest 1/3 of the population, the average height immediately goes up.
Similarly, if the small-footed lizards drop off the trees and can't find enough food, the average foot-size immediately increases in the population independent of evolution occurring. Evolution is 2-step process. The environmental advantage or disadvantage occurs during the individual lives of each member of the species. The passing of genes to the next generation is a separate process that still reshuffles the genes via sex relentlessly regardless of environment. That's what makes it hard to determine when evolution via genes is occurring vs purely environmental factors winnowing a current population. The new population of lizards still produces some amount of small-footed ones due to sexual mixing of genes--and if the environment changes to reward smaller feet, the population will again change quickly.
Maybe you don't understand the word: Evolution. Let me scope it out here for you.
You said that you believe in genes. Let's assume that you believe in the reproductive process too. When the genes of two parents combine you get all sorts of possible outcomes for the genetic result, or child. This child is then a combination of parental traits and yet not the mother nor the father. The child is new. We have also witnessed random mutation. You with me so far?
Now let's read the biological definition of the word Evolution:
"Evolution is the change in the inherited characteristics of biological populations over successive generations."
In conclusion:
If you believe that you are different than your parents then you believe in evolution. If evolution did not occur then you would be an identical twin of your father or mother.
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
It's not quite that simple, but you could probably simplify it to a few basic steps, like:
Is there a coding mechanism for heredity? - Yes, the genetic code.
Is there a way to generate new code? - Yes, mutation.
Does that code allow unlimited blending? - No, if it did the two sexes would completely blur together, among many other lesser examples.
Is there selection for fitness? - Yes, not everything gets to reproduce as much as it attempts to, and at least some of that is attributable to being "unfit".
Basically, people can point to examples where limited blurring may occur, or being taken out of the gene pool may have nothing to do with fitness (all dinosaurs are equally unfit to survive a 5 mile wide asteroid strike), or many other such factors, but they aren't really offering any effective criticism of evolution unless they want to claim things like selection or mutation never happen.
This is also why what Darwin did was science. His publication made several testable predictions - that there would be a genetic code, that the code could be altered on occasion, and that it would not allow unlimited blending of traits.
Who is John Cabal?
Evolution does not require "genes". Any biological or physical or even behavioral feature that allows information to be transferred to other members of the species, especially to new members of the species, can support evolutionary pressures. We can see it in social and cultural evolution as well as biological evolution, and they also in co-dependent ways. A great deal of child-rearing is learned behavior in more neurologically complex species.
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.)
No. Physics is real and math is abstract. It often provides close approximations of physical reality but it is not reality itself except in the sense that it is neurons firing in brains.
Apply pressure and see if the species DOES NOT adapt to the pressure.
That does not prove evolution by natural selection. Lamarkism would be an alternative explanation. Darwinian evolution not only predicts that species will evolve, put predicts a specific mechanism: The better adapted individuals reproduce more than the less adapted.
Most evolution is believed to be Darwinian, but there are Lamarckian adaptions such as epigenetic inheritance. Life is complicated.
I don't think the modern synthesis makes the claim that this process needs to be successful on a species basis, or needs to "save" or preserve certain populations or not in order to be true, which sounds like what you're proposing. Really all evolution claims is that (1) organisms change through generations, (2) these changes are subject to challenges from the environment and competition, and (3) changes that increase survivability in the face of these challenges will be conserved -- the changes are conserved, not the organisms themselves, the population or the species; these may all be lost in the process. The idea that this process must be "successful" or produce "better" or "more adapted" beings is not a necessary part of the synthesis.
I think the issue is you're seeing it teleologically. Wether something is "adapted" or not is to a large extent subjective, and in the context of evolution and natural history it's basically tautological. Evolution says, if it's alive, it's "adapted."
I'm not sure the claim that evolution is "causally exhaustive" is true, or even necessary in order to accept that evolution happens. Also I'm not sure where all this emphasis on "falsifiablity" comes from, Karl Popper is by no means considered the "exhaustive" authority on the philosophy of science. We can roll back and establish the evolution is a completely valid scientific concept, say, from a Baconian perspective, due to its practical insight and applicability.
Don't blame me, I voted for Baltar.
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.
In Biology, there's the concept of Stochastic Mutation. It's most commonly attributed to viruses, for example HIV is a known stochastic mutator. In these cases, some (not all, just some), types of cell mutations occur, where there's no selection pressure - the virus changes its protein coat in one of several ways (4 for HIV), and type B is just as likely to mutate back to type A or into Type C or D, as to stick where its at. In equilibrium, none of the protein coats is preferred by natural selection, and there's no pressure for one type to come to dominate. HIV also undergoes non-stochastic mutations, just like (we think) everything else with a genetic code does, and stochastic mutation has been studied for many other viruses and probably happens in more complex species.
That's the point - evolution is essentially a two part theory, a synthesis of Mendel's genetics including mutation, and Darwin's natural selection. Cases where all the organisms subject to selection pressure are identical, are not evolution*, and cases where the organisms are not identical but there's no selection pressure applied are not evolution either, and so there really are at least two categories of biological change which are not evolutionary. It's just that 'cases where there's no selection pressure' pretty much discribes some sort of paradise where nothing dies or is limited in how often it reproduces, so there are not a whole lot of known examples of that, especially over a long term, and it would be pretty expensive to create such an environment over a short term.
* If you had some organisms, and they have 0% chance of mutating in the particular way that responds to that particular selection pressure, then you could say that they are identical in that respect. Imagine for example a bunch of Leopards suddenly introduced to an environment where there are abundant fish in deep subsurface pools which can only be reached through narrow fissures. There's really no selection pressure sufficient for those Leopards to start adapting into creatures that can squeeze through six inch wide cracks and use their gills to dive deep enough to catch those tasty fish. All the Leopards are effectively identical, in that they are identically unsuited to take advantage of the new factor in their environment, tasty deep dwelling cave fish. However, I get a feeling you would reject generalizing that sort of example into one of the cases such as you are asking for, so let's just stick to Stochastic Mutation
Who is John Cabal?
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.
Who has made this assertion? Sure not TFA or really anyone else here. Or is this just your thing?
A lot of people including myself have given you examples of how it could be falsified, and you can only really get to the idea that it can't be by making categorically false assertions, such as "evolution demands that all change is evolution" or "evolution predicts that a species/a population/any arbitrary group of organisms will improve its fitness over time."
I mean if you don't like the evolutionary "worldview" with the blind watchmaker, the metaphysical naturalism, and the creeping utilitarian moral calculus, that's great. But not of that is required to accept the biological process as valid, nor does the biological process philosophically entail same.
Don't blame me, I voted for Baltar.
However, none of that is evidence that it is not designed.
Indeed. All we can say is that the theory doesn't need a designer. It doesn't need a painter or hair stylist either. Would you prefer if we rewrote the theory of evolution so that there was a hair stylist fixing the hair of the woolly mammoths ?
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...