Butterfly Unlocks Evolution Secret 1130
Anonymous Coward writes "The BBC has an article about a dramatic discovery in the quest for understanding evolution. From the article: 'Why one species branches into two is a question that has haunted evolutionary biologists since Darwin. Given our planet's rich biodiversity, "speciation" clearly happens regularly, but scientists cannot quite pinpoint the driving forces behind it. Now, researchers studying a family of butterflies think they have witnessed a subtle process, which could be forcing a wedge between newly formed species.'"
You didn't RTFA. (Score:2, Informative)
Re:Wasn't this obvious? (Score:5, Informative)
I can't really answer your butterfly question, but I can point out that every insect has multiple stages of life. Flies start out as maggots,
While we're asking the tough questions, it seems like the one big gun the Divine Design people have left is in the differing number of genes between species. If all offspring have the same number of genes as their parents, and all species on earth are evolved from one original life form, shouldn't all creatures have the same number of genes? Are there any theories out there regarding how genes are added or subtracted over time?
Re:Wasn't this obvious? (Score:4, Informative)
It is also very unlikely that full-blown metamorphosis arrived on the scene ex nilho. There is apparently ample evidence in the historical record for incomplete metamorphosis, via a 'nymph' stage.
You may find the following page interesting: "How did the process of metamorphosis evolve?" [madsci.org].
Re:This seems like half the story (Score:2, Informative)
Quoted from TFA:
"The reason evolution favours the emergence of a "team strip" in related species, or sub species, living side-by-side is that hybridisation is not usually a desirable thing.
Although many of the Agrodiaetus species are close enough genetically to breed, their hybrid offspring tend to be rather weedy and less likely to thrive. "
Re:This seems like half the story (Score:4, Informative)
But prior to divergence it wouldn't be hybridisation.
I suspect it's just poor wording on the reporter's part and the full story is something like:
There are butterflies of different species present in the same area. In order to prevent hybridisation they select mates on the basis of wing pattern. Some members of a species develop an abnormal wing-pattern. Although they _could_ breed with other members of the species, the inbuilt preference for mating with similarly-striped partners means they only mate with each other. This isolation of their genetic pool leads to an accumulation of mutations which make it impossible to breed with their ex-species. Now they are a new species.
(Also, I though hybridisation could be useful when there wasn't enough genetic variability in the parent populations.)
Misleading Article (Score:5, Informative)
The researchers didn't actually unlock any major secrets. It is no secret that two species who would not produce viable offspring together will try to avoid mating with each other. There are various mechanisms for doing that - having different wing colors so that species can distinguish their optimal mating partners is one method. If the two species are geographically separated, there is no need to develop other methods of separation, and thus their wing colors can look similar. There is nothing new about this.
Also, the BBC article never explains that the speciation of these butterflies occurred while they were geographically separated (this is called allopatric speciation, and the Nature article specifically states that the butterflies evolved this way). The species only developed different wing markings when they came back into contact with each other. This makes a lot of sense - they were now genetically very different, and offspring between members of different species would not be successful, so they needed ways of telling each other apart.
It's a nice finding, but certainly not the unlocking of a major secret.
Re:Wasn't this obvious? (Score:3, Informative)
By being born with little more than the ability to eat and move to the next meal they save the parent a huge amount of energy. Usually a parent creature has to drop a lot of their energy and food into incubating or laying an egg that will feed the young until they reach a fully matured stage.
With butterflies, flies and most other insects it becomes more efficient to lay an egg with only enough energy to create a rudimentary creature that does little more than eat and move to its next meal. This allows the parent to lay many many more eggs that have a chance of survival than if their eggs hatched directly into adult forms.
Now comes the fun part. The insect larva can slowly continue to develop into its adult form. It can develop wings, shed the extra legs change form as it matures. This is very bad for the species as it will eventually reacha point where it is niether lavae nor adult. It will go through some rather awkward stages where it becomes quite vulnerable. The earliest insects would likely have gone through this transformation as a gradual process while they ate, and probably wouldn't have a cocoon stage at all.
The species that will survive the best are going to be the ones that can hold off this transformation until they have enough food stored in their bodies to go hide somewhere. By hiding and going through the transformation in one go they avoid any awkward vulnerable stages (like developing large wings but having a body too big to fly). The ones that have the ability to create some form of protective shell (silk, folded leaves, or burrowing into the earth or into wood) have an even better chance of survival.
Basically the whole larva>cocoon>adult thing is to minimise the amount of energy the parent needs to spend on each egg, allowing more eggs and thus a greater survivability of the species.
Just an idea.
Re:Remember, evolution is just a theory. (Score:2, Informative)
I cringe every time I hear someone say evolution is just a theory. They don't understand what it takes to get to the next step beyond theory (law). Let me go back a hundred years... This guy named Einstein proposed that Newton's Laws of Motion may be incomplete when the numbers get reallllllllly big. Turns out he was right. Well, the scientific community felt a great amount of embarassment that something they had accepted as law was flawed. Since then, pretty much nothing has become a law, just in case it gets proved wrong.
So, evolution is a theory because that's pretty much as far up the ladder as things go these days!!! Not because the scientific community isn't quite sure. What most people think of as a theory (a conjecture that hasn't been thoroughly tested yet) is really called a hypothesis in the scientific community.
Read here rof a second opinion http://wilstar.com/theories.htm [wilstar.com]
Re:Those who don't learn from history... (Score:3, Informative)
Re:Observation alone proves nothing (Score:3, Informative)
Evolution and speciation has been observed (both in the fossil record and in the present day). These are the phenomena.
2. Formulation of an hypothesis to explain the phenomena. In physics, the hypothesis often takes the form of a causal mechanism or a mathematical relation.
Natural selection is the hypothesis to explain the observed phenomena.
3. Use of the hypothesis to predict the existence of other phenomena, or to predict quantitatively the results of new observations.
The natural selection hypothesis has been used to predict what kinds of new discoveries we should expect to find in the fossil record, and to predict how controlled breeding programs are likely to turn out.
4. Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments.
Many paleontologists over the years have discovered new "intermediate" forms, as predicted by natural selection. Animal and plant breeders have been independently experimentally verifying the mechanism of selection ("artificial" in this case, but the principle is the same - any controlled experiment is necessarily "artificial") in the evolution of species for a very long time now.
As I said before: evolution, the phenomenon, is an observed fact. A theory of evolution is an attempt to explain the observed fact.
Logic indeed (Score:3, Informative)
Ah. Well, as you are neither a creationist your own beliefs, nor, it would seem, are you interested in discussing the actual article...Logic would dictate that you are merely posting deliberately contentious material to stimulate. You are then, by definition, a troll. [wikipedia.org]
Q.E.D.
Re:Remember, evolution is just a theory. (Score:2, Informative)
Re:Those who don't learn from history... (Score:3, Informative)
First, hence the quotes around "disproved".
Second, the AC that also responded to you is right. Newton is never 100% right. However, with the speeds, forces, etc. we experience on a regular basis, Newton is so absurdly close to being correct that it works just as well as Einstien, and the errors that simplification introduces are more or nothing compared to measurement errors.
The mathematics of evolution (Score:5, Informative)
theory is a theory my friend
Every field of science is a theory, my friend. Everything from the theory of the atom to the theory of zymosis (that's fermentaion). You may as well try to attack relativity as being "just a theory".
sortof like the unprovable assumption of evolution?????
What unprovable assumption of evolution? Evolution fundamentally says that if if you have heritable variation and mutations and selection pressures on that variation then you will get evolution over generations. This is trivially observable fact. There is no genuine scientific dispute over biological evolution exacly because there is so much evidence that cross checks and cross validates across so many feilds, both current observations and study of prehistorical evidence left behind. Trying to even scratch the surface of this mountain of evidence in this post would be hopeless. If you are questioning the quantity and quality of the evidence, I suggest you either crack open a text book on the subject or at least browse the talkorigins [talkorigins.org] website. It's all well documented if you actually question the issue. If you don't truely question the issue and you instead simply reject the entire subject on non-rational grounds, well obviously you're not going to be swayed by something silly like actual evidence and actual science.
Anyway, the real issue I wanted to address was this one:
the sheer numeric improbability of evolution
Correction, the sheer numeric CERTIANTY. There's powerful mathematics to evolution, powerful effects going on that you don't hear about in the common explanations of evolution. The common idea of evolution is as a sequence of individual beneficial mutations, like climbing a ladder. If that's how evolution actually worked then critics would be right, it would have been mathematically impossible for evolution to produce the incredible complexity we see today.
To show the true mathematical power of evolution I will first abandon that "ladder climbing" of beneficial mutaions. In fact lets assume that every single mutation that occurs is either neutral or harmful. I'll demonstrate that we still get the real and powerful mechanism of evolution, the math of evolution.
A good place to start is with the common complaint of creationists that mutation and evolution "cannot create information". Well in the initial mutation phase they are right. When a mutation occurs it introduces noise, it tends to degrade information. But look what happens the moment that mutation gets passed on to an offspring. That mutation is now no longer random noise, it now carries a small bit on information. It carries a little tag saying "this is a nonfatal mutation". The presence of this mutation in the offspring is new and created information, the discovery and living record of a new nonfatal mutation. Over time the population builds up a LIBRARY of nonfatal mutations. This library is a vast accumulation of new information.
That information actually undergoes even more processing and synthesis. Over generations beneficial mutations would obviously multiply, but we're assuming there are none of those here. However entirely neutral mutations will also tend to accumulate and multiply. Nearly harmless mutations would also accumulate and multiply to a lesser extent. Somewhat harmful mutations will even accumulate, and extremely harmful-but-nonfatal mutations will pop up and disappear at the rarest frequencies. So not only do we build up a library of nonfatal mutations, the mutations get tagged with a tagged with a frequency, the percentage of the population carrying that mutation. Each mutation is tagged with a measurement. Every mutation now carries a cost/benefit information tag at the population level. The best ones have a high percentage representation and the most harmful ones have a near
The Beak of the Finch (Score:2, Informative)
http://www.amazon.com/exec/obidos/tg/sim-explorer
For an excellent run down on evolution.
Btw... I think this book shows clearly that evolution is _not_ a theory.
One of the more interesting expirements conducted was with tropical fish in South America. More or less there are several species of small river fish. Higher up the mountain the fish are striped, lower down the fish are spotted.
A scientist introduced fish from the bottom (spotted) of one river into the top of another river that had none of these fish. They watched and observed and over time... lo and behold... at the top of the new river there where stripped fish, and at the bottom spotted fish.
The utility of stripe vs spots is attributed to effectiveness of camoflage. At the top of the river, in mountainous terrain, strips work better (overhead foilage is rare). At the bottom of the river spots work better (overhead foilage is common).
There were also some very interest graphs, though without the supporting math, that illustrates a correlation between resource availability (food and water) and speciation (this pertained specifically to finches).
Anyways it was an excellent read (won a pulitzer).
Very common questions: FAQs of answers (Score:5, Informative)
For your specific points, these are very common questions / issues from creationists and others (except the bone question), so the Index is useful:
Re:Intelligent Design, explained Intelligently (Score:2, Informative)
You are obviously very unfamiliar with the arguments to keep Intelligent Design out of science classes. "Right" and "wrong," as concepts, are topics for religion, not science. Science is about "supported" and "unsupported" by evidence. I haven't heard scientists say it's "just wrong", I've heard them say its unscientific. Even if Intelligent Design is 100% correct, it would STILL be unscientific-- it would just show that science is unable to explain everything.
There are no "facts" in science, only observations and conclusions. Every testable explanation is a "theory", so saying something is "only a theory" is the scientific equivalent of saying something is "only an explanation that can be tested". Casting intentional doubt on science for the sole purpose of promoting religion is really hurting this country, I think.
The bottom line is that Intelligent Design is not "falsifiable"-- there is no experiment you can use to discredit it, since any result of any experiment can be explained by saying "God/Aliens wanted it that way." You say that the "true scientist withholds judgement until the experiments have been done," which is a good sentiment. However, now that vast numbers of experiments/observations HAVE been done, many scientists are justified in defending evolution. And if anyone ever comes up with an experiment that can be done to support/discredit Intelligent Design, it would be a boon to science to perform the experiment, and I'm sure it would make headlines on Slashdot.
Re:Wasn't this obvious? (Score:5, Informative)
Some insects (e.g. locusts and cockroaches) basically look more adult (bigger, better wings, etc) with each instar (period between moults.) This guys need to act like adults from the time they are hatched (although some species actually have the parents nurse until the offspring are developed enough.)
For insects laid on carrion, ripe fruit, edible plants, and other transient food sources, time is of the essence: hatch fast, be a sac with a mouth, eat all you can, then pupate and get to the complex, energy-expensive adult stage in one moult.
Note that simple cocoons are nothing more than hardened/dried outer skin - it's just a moult.
Because markings become a neutral trait? (Score:3, Informative)
Once humans stop natural selection and start applying our own standards of selection, camoflauge becomes a neutral trait: we, not camoflauge, protect the flock or the field.
Re:Wasn't this obvious? (Score:3, Informative)
Probably. But an excellent book about such topics is Song of the Dodo [barnesandnoble.com], by David Quammen. In it he writes about island biogeography and examines what happens evolutionarily when species are cut off from the main group. It's a fascinating and fun read and includes details both about Darwin and Alfred Wallace, who may have beaten Darwin to the punch in actuality.
I wasn't trying to make an exhaustive list (Score:5, Informative)
My favorite refutation of the bogus Second Law criticism is a seed in some soil in a terrarium. You add nothing but maximally-entropic hydrogen and oxygen in the form of water, maximally-entropic carbon and oxygen in the form of CO2, and sunlight. The seed will sprout and proceed to reduce the entropy of those raw materials in its own growth. The fundies who assert the 2nd Law don't realize that the system creates huge amounts of entropy; it's just leaving in the form of the ~300K waste heat that was once the 5700K solar blackbody spectrum.
This is silly (Score:3, Informative)
For instance, one of these mechanisms is spatial segregation, in which some members of a single population become physically separated from another group of that population, by some phenomenon (think changing tidal patterns/river flow paths). This physical separation causes reproductive segregation/separation that leads to speciation by non-shared mutation.
Another is behavioral segregation, which has been mentioned in this thread (orcas hunting fish vs hunting mammals), which leads to social exclusion and, again, reproductive segregation.
Finally, there is selective segregation, which refers to segregation of members of a population due to proficiency at some task necessary for survival. For instance, the Darwin Finches of the Galapagos Islands are under quite strong selective pressure surrounding the size and shape of their beaks. Some finches with long and thin beaks are able to feed on fruit that has small holes in the fruit body, while other members of the same species have larger and stronger beaks that they may use to crack open other kinds of seeds. When food is plentiful, both phenotypes are able to get along just fine on seeds and fruits that lie inbetween these extremes, but when selective pressure is applied (in the form of a famine, perhaps), this small phenotypic difference in beak size/shape results in survival for these two, now more genetically distinct, genotypes, while those finches that fall inbetween the two extremes tend to not survive. If such a selective pressure (famine) lasts for long enough, the two resultant populations may achieve speciation. All of these mechanisms have something in common, they all require reproductive segregation of some sort. This research is all at least 10 years old, and this article is just scientific fluff.
For an extremely interesting and pertinent read, try The Beak of the Finch: A Story of Evolution in Our Time by Jonathan Weiner.
Re:Misleading Article (Score:1, Informative)
Either you don't get it or you're way oversimplifying the problem. Creatures don't have inter-species conferences about "problems with members of different species trying to have sex" and draft an Ecuador Accord that says "from now on every separate species of butterfly must have different wing coloring in order to prevent embarassing attempts at inter-species reproduction." These things happen naturally and gradually over time (according to the theory of evolution).
And there are many questions here that may or may not have been answered: Do the butterflies really use the wing colors to distinguish different species, or some other mechanism (maybe the color is obvious to just us humans)? How come every different species so conveniently has different wing colors? Does every different wing color mark a different species, or are some butterflies refusing to mate with different-colored others mistakenly? etc.
Re:Observation alone proves nothing (Score:3, Informative)
That is so very false that I am baffled. For starters I think you mean that acceleration due to gravity [wikipedia.org] is about 9.8 merters per second squared. That's acceleration, not velocity.
And indeed a feather and a stone will always accelerate at identical rates. Their maximal or terminal velocities may differ significantly however, as the maximum velocity that can attain is determined by the amount of resistance they recieve from the medium they are falling though. A feather receives far more resistance in air than a rock, and hence has a much lower terminal velocity and may reach the ground later. The acceleration is the same, but the velocity is different. For somethign different try changing the medium instead of the object: drop a stone in air, and for the same distance through water. The water provides more resistance so the stone will have a lower maximum velocity in water and hence will fall more slowly.
HTH.
Jedidiah.
Re:Carl Sagan: Shadows of Forgotten Ancestors (Score:2, Informative)
http://www.iscr.ed.ac.uk/mecp2/mutations.php [ed.ac.uk] (random result of web search. First one I looked at.)
And, how does one underestimate a fact? More like, never underestimate people's ignorance about biology.
Just a theory (Score:3, Informative)
In science, a theory isn't a guess or a hunch - it's something a great deal stronger than that. A scientific theory makes testable predictions that can be verified by observation.
Re:The Beak of the Finch (Score:3, Informative)
Field theory (i.e. propogation of things like light and radio waves) is a theory, but no one would deny their existence. A theory doesn't mean "well it's just our best guess" or "we're not sure" - a scientific theory is generally a set of predictions that can be tested by observation (either experimentally, or just looking outside or both). A theory is actually a very strong thing as it is something that can be proven or disproven and refined. This latest story is about an observation that confirms more of evolution theory.
The mistake the creationists are making when they say "it's just a theory" is that they totally misunderstand what a theory is. They are thinking that a theory is merely a hunch or a guess. A scientific theory can be (and often is) something that contains many established facts or may be entirely made up by established facts. Creationists are trying to make out that a theory is a guess, and they are so wrong in their understanding of what a theory is that they aren't even wrong.
Re:We have an experiment, and ID fails (Score:3, Informative)
This is assuming a perfect creation. Evolution is full of metaphysical assumptions, but pretends its not. See Darwin's God: Evolution and the Problem of Evil [amazon.com]. His main point is that the biggest problem of evolution is not its metaphysics, but its denial of its metaphysics.
Anyway, let's look at some flaws in your assumptions:
1) God would make each creature perfect. In fact, God specifically said he made some creatures persue folly by design.
2) Each creature currently is as it was created. Would not a good engineer make a creature adaptable?
3) Each creatures is as perfect as was originally made. But Biblically, all creation was affected by the fall.
It sounds like your arguments are from Gould. Gould was a great writer and an excellent thinker, but he failed to see (or even possibly know about) how the fall would affect biology. Understanding the Pattern of Life [amazon.com] has a great chapters on both biodiversity and biological imperfection. While it probably isn't enough to convince a skeptic, it would probably be useful for skeptics to at least understand the creationist perspective.
Most people also don't understand that both creationists and evolutionists believe in evolution [blogspot.com], the main difference being that creationists believe in a polyphyletic tree, and that biodiversity was built-in [grisda.org] while evolutionists think that it was not built in [blogspot.com].
Re:Mind and Big Mind (Score:3, Informative)
I am not suggesting that your beliefs are wrong or invalid. I suggest that we speaking about them, that you delineate belief from knowledge, without implying that one is inferior to the other. In fact, one can say that knowledge is inferior because it is composed of possibly flawed conclusions drawn from a limited number of observations, whereas beliefs (and Faith) are pure, perfect, universal, and irrefutable. So keep your superior beliefs out of inferior Science (and vice versa). This point is especially valid when discussing ID, because Christian Fundamentalists want their beliefs taught as knowledge in Science classes.
Science is about knowledge, not Truth or Belief or Answers. The state of Science at any given moment is basically: these are the few things that we know, and here are the observations (direct or indirect) that cause us to know them. And BTW, please show us that the conclusions that we have drawn from these observation are incorrect, because that is the means by which our knowledge grows in both quantity and quality.
Re:Intelligent Design, explained Intelligently (Score:3, Informative)
many, many ways [talkorigins.org]
Re:Intelligent Design, explained Intelligently (Score:3, Informative)
This is dumb. We have an adjustable pupil in our eye as well as photoreceptors that adapt to light. The tiny bit of light absorbed by the layer of cells at the back of the retina does not help at all. All it does is scatter the light a bit and reduce visual acuity.
It also acts as a UV-filter, which squids living under water, don't need.
Wrong again. Those cells are virtually transparent to UV and provide no appreciable protection. As a matter of fact, birds, who have the same eye design as we do, can see UV. Besides, those cells are neurons that are required to see. They are the cells that need to be protected from UV. So having them absorb UV would be exactly the wrong thing to do if you were trying to design an eye.
Furthermore, the blind spot costs us nothing, since we have two eyes(=most of the time the blind spots don't overlap), and (unless we focus them) they are moving constantly, so nothing can hide in the blind spots.
But why have a blind spot at all? Yes, we've adapted so that they are only rarely a problem. But an object coming at you rapidly from your blind spot could put out your eye because you wouldn't see it coming to blink. And if you lose one eye, which is not that uncommon an injury in the wild, you will be even more vulnerable. It provides no conceivable advantage; no intelligently designed light sensor runs the wiring in front of the sensors.
The word "species" is not defined by reproduction (Score:3, Informative)
Re:Geek speciation (Score:1, Informative)
Re:Wasn't this obvious? (Score:3, Informative)
Re:The mathematics of evolution (Score:2, Informative)
The do part was a simple chem simulation that shows that even without the myriad of potential chemical reactions that are possible with real chemistry, that as long as some combinations would be catalysts for other reactions (either constructive or destructive), that self catalyzing systems would evolve.
From this, it's not hard to imagine ponds in the proto-earth with their own chemical chains. Geologic events and even just the hydrological cycle would mix these ponds together in part or whole, leading to new chains and to more complex molecules. Some chemical sequences would be destroyed by mixing in a very similar process to evolution.
At some point, a chemical chain manages to make a wall to block out contaminents. Somewhere, DNA or RNA or some precursor that performs the same function comes about and because of the advantage it provides, spreads rapidly. Combine the two and you've got a very basic cell.
Re:Intelligent Design, explained Intelligently (Score:2, Informative)