Warm-blooded Fish? 342
DIY News writes "Scientists now have direct evidence that the north Pacific salmon shark maintains its red muscle at 68-86 degrees Fahrenheit, much warmer than the 47 F water in which it lives. The elevated muscle temperature presumably helps the salmon shark survive the cold waters of the north Pacific and take advantage of the abundant food supply there. The heat also appears to factor into the fish's impressive swimming ability."
Other warm-blooded "cold-blooded" creatures (Score:5, Interesting)
For example. Honeybees generate heat in the winter to keep the hive warm and use heat to kill predatory wasps [sciencenews.org] -- surrounding the wasp, heating up to 45 C (113 F) and killing the attacker.
Not surprising, and not really "warm-blooded" (Score:5, Interesting)
On the one hand, practically every poikilotherm that's been studied actually thermoregulates in some ways. Very few of them truly assume the temperature of their environment.
On the other hand, "maintaining" temperature at "68-86 degrees Fahrenheit" -- 77 degrees plus or minus 9--is far from comparable to the degree of thermoregulation shown by mammals. Nine degrees too high or too low is enough to kill you, and most mammals.
It's interesting to learn how another kind of poikilotherm performs a crude kind of thermoregulation, but by no means earthshaking.
I thought there were a bunch (Score:5, Interesting)
Disadvantage too? (Score:1, Interesting)
Wouldn't this also make it easier for predators to find them? How sensitive are marine predators to heat?
Obvious ... (Score:1, Interesting)
Use these sharks and they don't have to carry separate frickin power supplies for their frickin lasers. Power straight from the sharks themselves (kinda like geothermal).
Re:Other warm-blooded "cold-blooded" creatures (Score:3, Interesting)
You did. Thermodynamically, extra effort is extra effort, even if that extra effort involves burning calories to produce a special behavior rather than burning calories to feed a special organ. Evolutionarily, it doesn't really matter--in fact it makes sense--that many different mechanisms evolved toward the same general end. A species that already accomplishes a particular goal in one manner probably won't evolve toward a different method unless some other advantage comes with it.
More interesting than the sharks in the article, I think, is the eye-heating organs [nih.gov] that marlin and sailfish have evolved. The last theory I read is that helps them see more clearly, for hunting, in the deep cold water. They evolved just enough to accomplish the goal and no more. Give them a couple of centuries of much colder water, and I'm sure they'd end up heating their whole blood supply, too.
Re:So... (Score:3, Interesting)
Evolution is a scientific theory. ID is only a theory in the loosest sense of the word.
Perhaps you could explain what there is to scrutinize in ID. It amounts to nothing more than a god-of-the-gaps argument with the premise "somehow something somewhere is wrong with evolution". Heck, guys like Michael Behe don't even deny that evolution happened, but ID is starving for substance that it can be adopted be Young Earth Creationists just as easily as by a theistic evolutionist. This is because it actually says nothing at all.
Science isn't about truth, but evolution is the best explanation for the data. ID explains nothing, and is specifically designed not to. It's a political ploy to sneak Creationism into the public school science class.
Re:So... (Score:3, Interesting)
Interesting...
Re:So... (Score:0, Interesting)
Both ideas have their downfalls and their merits. Your argument, however, is somewhat misleading.
What is observable and testable in said bacteria and insects is not, in fact, evolution, but rather natural selection and intra-species adaptation; the emphasis of "strong" traits in the gene pool as opposed to "weak" traits.
While it is certainly irrefutable that a species itself can change over the course of time, as this is observable, it is another thing entirely than to presume that, even given millions of years, one species becomes another entirely different species.
To put natural selection briefly: The cause of variations in the genetic code is a number of miniscule mutations, some of which are helpful, and some of which are harmful. Those individuals which receive 'helpful' mutations are more likely to pass on those mutations, as opposed to those who receive 'harmful' ones.
Many of the traits that give individual species their unique, niche ability to excel in their own habitat require far more than a slight mutation to actually give them an advantage.
As an example, the horned toad has the ability to literally squirt blood from its eyes in order to distract and startle predators.
One change, but requires various changes to the genetic code to be functional; the actual sac that the blood builds up in, the duct that the blood is projected through, the muscles around the sac that constrict to project the blood, the nerves that enable the muscle to contract, and the instinct to use this ability are all different parts of the genetic code, and without any one of these traits, the ability will not work, and the changes do not give the toad an advantage.
Mathematically, it's possible that all of these traits appeared simultaneously, but it's also an extremely minute chance.
Additionally, the 'jump' from unicellular organisms to multicellular organisms is a bit of a stretch. What kind of a genetic change is required to make the difference between a 'colony' of individual unicellular organisms to become one single multicellular organism?
Furthermore, the mitochondria and chloroplats found in various cells are believed to have originited as parasites that eventually began to help their host. But these organelles are now a part of each cells genetic code. We already know that traits acquired through an organisms lifespan do not change their genetic code, and a parasitic organism is hardly a trait either.
There are myriad things like these that just don't stand up to the kind of scrutiny that science demands; all theories, scientifically, must be considered to be false until they can be proven; this is how the scientific method works.
Now, admittedly, none of this holds a candle in lack of credibility to the assumption that it was all done by some mythical, supernatural being... however, neither theory is sound enough to declare fact. I'm not willing to declare either as fact, and to cite either fact is belief, religion even. Not science. I find it ironic that so many atheists and agnostics are so religious in their belief in evolutionism, and so many theists try to support their unprovable belief and faith with science.
Science and Belief are two different things.
Remember the scientific method.
Re:I thought there were a bunch (Score:2, Interesting)
Rattlesnakes also warm blooded (Score:2, Interesting)
Re:I cast my vote for evolution (Score:2, Interesting)
While I understand your interest in the evolutionary mechanism, I'm not sure that's the right way to look at it. I don't think any creature is ever done. At best, a species achieves a relatively stable period where its configuration--for want of a better word--matches its current environmental conditions.
We like to think of species as something strictly-defined and set in stone, but they aren't, really. Not is the long term. In the long term, they're always somewhere between what they were and what they will become. At best, a species is a way of saying "from this time to that time, this organism had this configuration."
Re:So... (Score:1, Interesting)
Also, biologists aren't just making shit up when it comes to new species descending from ancestors. There's plenty of evidence that suggests this is what has happened.
If you know of any specific barrier that prevents new species from descending from existing species, please describe it.
Re:So... (Score:5, Interesting)
It also matters because ID is not science. It is not testable. It is not falsifiable. It isn't even a theory save in the most general and non-specific meaning of the word. More importantly however, is that public schools in the US are not supposed to be places of religious indoctrination, and ID is formulated as a legalistic scam to sneak Creationism past the 1st Amendment.
Evolution is not a religion. It is not a bit of wild-ass speculation. Not all ideas are created equal, and in the world of science there is no debate. Any theory that seeks to replace evolution is going to have to explain the evidence, and DesignerDidIt explains nothing whatsoever.
Re:So... (Score:2, Interesting)
I hear this one a lot, but I don't think it is valid. Since we are talking about a large number of random events that just happen to randomly occur in one organism to produce a useful trait, I compare it to asking somebody to pick a number from one to infinity. The odds of picking the number 1,234,543 are essentially zero, but I picked it anyway. According to the logic of hardcore ID believers, because the odds were so small, it must never have happened.
Re:So... (Score:3, Interesting)
All I can say, is that I foe everybody that has "free stuff" in their signatures or their "homepage" here on slashdot, and it really increases the signal to noise ratio.
I'm getting sick of seeing this crap about "Intelligent Design" vs evolution. Also, I have never heard of an evolution zealot until this post.
No, ID nor evolution can be "proved". Proofs are only valid in a self contained system like mathematics, everything else is evidence.
My question to all of the ID zealots, is this. If I were able to prove to you that ID was real, and nobody could discredit it, what the fuck would that get you? What is that knowledge going to benefit your life?
I don't believe in evolution 100%. Seems pretty good, but I would not be upset in the least if a better supported theory came around. I'm sure that everybody looked to the south-west and stomped their feet 5 times when Newton's laws were not found to be laws, because they broke down at the subatomic level and at high speeds.
The theory of evolution gives us things like genetics, selective breeding, and an understanding of why different species exist at a point in time, why they disappear, and rapid changes in species are good indicators that there is something radically different in their environment.
Again, what would 100% proof of ID give anybody?
Dinosaurs disappeared because the Flying Spaghetti Monster stopped anointing them with His Noodly Appendage, thus giving rise to the human race to do His noodling for Him.
That is a great story to tell kids. Its entertaining. But outside of that, its nothing.
Fish != fish !? (Score:3, Interesting)
Shark != Bony Fish, Sharks = Cartilaginous fish
The distinction is important, because taxonomy-wise, that makes them as different from 'fish' (bony) as mammals, amphibians, reptiles or avians. It's a split at the class level. A warm blooded shark is not as impressive as a warm blooded bony fish would be.
Of course, since chondrichythes (cartilaginous fish) and osteichythes (bony fish) still contain the word chythes (fish), sharks are still refered to as 'fish' but biologically, they're just as different as the other classes. They just also happen to look kind of the same.
The same mistake is often made between reptile and amphibian, or aracnids and insects, etc.
But... (Score:1, Interesting)
Re:I thought there were a bunch (Score:2, Interesting)
http://www.americanscientist.org/template/Current
It talks about how and why tuna and lamnid sharks have elevated muscle temperatures. Has to do with the way they swim. The neat thing is it explains why tuna and these sharks have that stiff-bodied way of swimming. The warm muscles are deep in the body along the spine, but pull tendons that move the airleron-like tail to propel the fish. They say that tuna have been clocked at nearly 70 mph for short distances.
Contrast this with regular fish, which swim by bending their entire bodies back and forth.
Another interesting thing is that the tuna and sharks have to swim constantly their entire lives or they will sink - no air bladder. The lack of a bladder meant they could descend much faster onto prey. As a result they literally must swim or sink.
Re:Fish != fish !? (Score:3, Interesting)
So you reject outright the entire concept of cladistics?
That's your right, of course. But it does rather put you outside the main branch of evolutionary biology these days. (Not That There's Anything Wrong With That
According to the cladistics terminology, we didn't separate from the fish; we are [a branch of the] fish. Granted, we're funny-looking fish, since we're adapted to breathing air and living on land. Our fins are heavily modified to arms and legs, and our scales are skinny hairs. But if you look at the tree that includes all the things we call "fish", mammals are a part of that tree, so we're fish, too.
If you don't agree, then your definition of "fish" isn't a clade, so it's a bogus classification. It's ok as a term in common English, but it's not a biologically meaningful classification term.