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Butterfly Unlocks Evolution Secret
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.'"
IANAEB (Evolutionary Biologist), so I'm just going by the article here, but it seems like the process itself was obvious (or at least pre-supposed) as you suggest, it's the chance to witness it in nature that's exciting here.
... that's all i got. IANAEntomologyst either.
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?
While we're on the subject, I might as well reply to myself and point out a selective advantage to multi-stage lifecycles, namely that the different stages do not compete with each other: they eat different food, and fill different evolutionary niches. This means that in times of scarcity there is little advantage in adults behaving like those of some non-metamorphising species, who will kill youngsters, as they are in direct competition with them for resources.
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?".
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This article from the BBC is misleading. I tracked down the original article in Nature.
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.
First two minor points, then I'll get to the real subject, the math of evolution.
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 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
- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
For your specific points, these are very common questions / issues from creationists and others (except the bone question), so the Index is useful:
It's actually even simpler than that: insects, because of their hard exoskeletons, usually moult (or shed their hard body) a couple of times throughout their lives: it's the only way they can grow.
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.
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.
Time is Nature's way of keeping everything from happening at once... the bitch.