Slashdot Mirror
Shark 6th Sense Related to Human Evolution?
An anonymous reader writes "Scientists at the University of Florida are claiming that certain genes found in sharks that give them their 'sixth sense' and allow them to detect electrical signals could also be responsible for the development of the head and facial features in humans. From the article: 'The researchers examined embryos of the lesser spotted catshark. Using molecular tests, they found two independent genetic markers of neural crest cells in the sharks' electroreceptors. Neural crest cells are embryonic cells that pinch off early in development to form a variety of structures. In humans, these cells contribute to the formation of facial bones and teeth, among other things.'"
...do different things in different organisms. This is not news. It is a study of cellular fate in two different biological contexts of distantly related organisms.
Which of these cells pinch off to form friggen laser beams?
You're nothing; like me.
It seems we get a new "sixth sense" every few months. Perhaps it's time to review the whole "five senses" thing so that people stop using "sixth sense" as if it's something special or supernatural?
So this is why I was born with a dorsal fin
maybe our teeth can pick up radio stations someday :)
As they evolved, mammals, reptiles, birds and most fish lost the ability. Today, only sharks and a few other marine species, such as sturgeons and lampreys, can sense electricity.
The platypus begs to differ...
A shark's 6th sense.
"I see soon-to-be dead people"
You misspelled laser.
Have you ever, while having your eyes closed, felt the position of a pointy object several contimeters distant from you face, especially from your forearm? I did and many people know that feeling. I have no idea whether this is an electrostatic field or what, or if it has anything common with... sharks, but it is probably quite a common phenomenon. I do not really know why I have not seen it described anywhere in the literature.
In a directly related story, scientists have found THE missing link between sharks and humans in a sub-species. They are calling it entrepreneurius-maximus.
Offer not valid in NY, Conn., CA, MA, etc.
Cogito Ergo Sum
Common (backboned) ancestor with (they think possibly) an electro-whatever sense
Demented But Determined.
Most fish have some electrical sense, though some may do it better than others. I'd guess this sense was re-invented many times.
Terrestial animals, including humans, can feel strong gradients in the air before thunderstorms.
6th sense: Your "stuffy room" sensor for excess CO2. 7th sense: Infrared sensors around your lips: Close your eyes. Put your hand three inches from your face. Feel the heat around your lips? 8th sense: Your ears can correlate pressure changes to detect that you're between walls.
The scientific method is pretty much the definition of how you aquire science (systematic knowledge). To agree or disagree with a definition does not make much sense.
;-)
However even if a model or theory cannot be scientificly proven or disproven it might be of use anyway, for example: mathematics is in fact not a science since it is derived from axioms (fundamental concepts *belived* to be true). Even so, no scientist would deny the usefulness of mathematics
They'll be happy to know that they haven't evolved from monkeys after all!
"Human evolution" is just a theory.
If you don't believe me, ask the next A&M dropout you meet.
Sheesh, evil *and* a jerk. -- Jade
Yes, the single-cell southeastern australian wombat.
I don't think that's very plausible. After all, humans claim to have ESP and what's that supposed to be? Detection of electrical impulses from just into the future?
'sixth sense' and allow them to detect electrical signals could also be responsible for the development of the head and facial features in humans.
Actually, I saw Sixth Sense and what it really allows sharks to do is see the ghosts of dead sea-life which lead them to the carcasses. Shit, I thought everyone already knew that.
A feeling of having made the same mistake before: Deja Foobar
"Evolutionists" don't have an agenda, unless you count science as an "agenda." We don't consider science to be subject to public policy, and as such, laymen don't get a vote.
This has absolutely nothing to do with evolution
If you believe in the general concept of "science" it absolutely does.
My point isn't to try and start a flame war, just simply that it's poor journalism to take something completely irrelevant to origin of life
Read the damned article. They're talking about the same stem cells in the embryo developing into electrosensors in sharks and ears in humans. That absolutely has everything to do with embryonic development which is known to mirror vertebrate evolution, at least to those who follow science.
It makes for bad science.
Are you a scientist? Because among actual scientists, evolution is as much an established fact as gravity. Don't fall off the edge of the flat earth on your way out the door.
found in sharks that give them their 'sixth sense'
The shark turns out in the end to be dead all along.
There's a saying in developmental biology circles that neural crest cells are the only really interestng part of vertebrate embryology. They form (IIRC) the autonomic nervous system, endocrine glands and pigment-producing cells too, as well as the ganglion of the auditory nerve - which is why some animals show a link between colouration and deafness.
It implies that millions of years ago, intelligent sharks decided to break their ocean bondages by entrusting man with a gene that would determine our facial features and give them an avenue to bombard us with subliminal pop-up ads that will someday drive us to take to the stars; among the species we will take with us to our new home: sharks. This theory fully correlates with evidence that mankind has evolved into a society that craves iPods, has basic knowledge of celebrities, and possesses an insatiable desire to squash the cockroach/bomb Sadaam/catch Santa/raid the cookie factory.
"There are some people that if they don't know, you can't tell them." ~ Louis Armstrong
> I disagree that science is restricted to that which can be demonstrated using the scientific method. Humans have been engaging in scientific inquiries for millenia, yet the scientific method is a recent invention. The scientific method facilitates the acquisition of scientific knowledge, but it is not the only possibility. There are times when performing a scientific experiment is impossible or immoral. In these cases, we can still make observations and construct models, even though we cannot directly test those models.
It sounds like you're saying that "the scientific method" = "laboratory experimentation". If so, that's not correct. Astronomy, for example, uses the scientific method.
Also, "directly test" is a pretty slippery concept. Arguably nothing is direct, e.g. when we weigh a compound we are getting its weight indirectly (through whatever mechanism the scale uses), and we only see the output via the photons that our retina catches.
Sheesh, evil *and* a jerk. -- Jade
It just implies that sharks and us, remotely related as we are, use a common toolkit to specify seemingly different kinds of things, such as electroreceptors and neural crest cells in humans. The former may be neural crest derived. So are many receptors in our skin. It does not mean that we are descended from sharks in any way. We are related, as all life is. Nature abounds with examples where very remotely related genera will use very similar genes to specify tissues with similar functions but very dissimilar compositions. The same gene that specifies eyes in the fruit fly for instance specifies eyes in us humans. Yet our eyes are not like those of a fly at all. The gene says "Make an eye here". The same will apply to electroreceptors in sharks and neural crest derivatives in humans. One of the genes might say "migrate here and make this receptor", regardless of the identity of the receptor. A gene is a tool, like a hammer. It is not the blueprint.
----- One learns to itch where one can scratch.
"Evolutionists" don't have an agenda, unless you count science as an "agenda."
I'm going to have to disagree slightly here. There are evolutionists, and they do have an agenda. There are also scientists, most of whom believe in evolution. I think the line can be drawn when people make statements as facts, like in GP pointed out that the author of the summary did, instead of stating the simplest hypotheses which has not been disproved by any observational evidence. Since we use these same mechanics for drastically different purposes might it not be a better hypotheses that different species use the same mechanisms due to the unique properties rather than assume a shared ancestor?
Computers allow humans to make mistakes at the fastest speeds known, with the possible exception of tequila and handguns
Now they's saying we evolved from sharks? What will those heathens say next?! Pfff, probably that we evolved from bacteria!
Don't lead me into temptation... I can find it myself.
If I were asked to guess what embryonic tissue shark's electroreceptors came from, my first guess would be neural crest. After all, this is the tissue that gives rise to electrically active tissues like nerve and muscle, which have receptors that do indeed "sense" electrical fields. This is not to allow the animal to sense electrical fields in its environment, but simply the way nerve conduction and muscle contraction work--a change in electrical field (typically produced by a chemically activated ion gate in a membrane) is "sensed" by a voltage-gated ion channel that responds by opening up additional channels, further altering the electric field, which stimulates other voltage-gated ion channels, and so forth. It is easy to see how such a process could be evolutionarily adapted for sensory purposes, just as fish that generate strong electric fields, such as Torpedo (the electric ray) do so with tissues that are evolutionarily derived from muscle.
So basically, all this is saying is that we and sharks have a common ancestor and as a result share similarities in the development of nervous tissue (which we knew already), and that sharks' electro receptors develop from the tissue that any biologist would identify as the "usual suspect."
Anyway, one of the hard-to-pin-down aspects of shark encounters is a "sense" people report having just before they become fully aware of a big shark's presence. This may just be memory colored by the adrenaline rush that came with the encounter -- but it's very commonly reported that, moments before the water starts boiling or whatever, the surfer gets a cold, "something isn't right here" feeling.
(Which would also be a touch of an evolutionary advantage for the person able to sense it, yeah?)
"Fundamentalism" isn't about divine morality. It's about human authority.
Yeah. He was wrong. That's OK. Trouble is, he was wrong about just about every single thing he tried, and then got cited as an unassailable authority by just about everyone in Europe for over a thousand years.
Real Daleks don't climb stairs - they level the building.
Let us just say that the preponderance of evidence supports the theorey of evolution. Something that can not be said for creationism as explianed in the bible.
You are right, of course, bad science is everywhere you look. There will be scientists who believe in creationism, even blindly so. Afterall, we are all inherently irrational creatures and scientists are no exception.
Science, on the other hand, strives for the most rational explanations. And when the Grandparent said: We don't consider science to be subject to public policy, and as such, laymen don't get a vote. I think I can safely translate him to mean: Science cares not for an individual's desires, only for the truth
I agree. To generalize a bit and throw in some random thoughts, the word dogma comes to mind when I read many posts about science on Slashdot. Here is a definition of dogma from Wikipedia:
"Dogma is belief or doctrine held by a religion or any kind of organization to be authoritative and not to be disputed or doubted."
In my estimation that definition describes a lot of Slashdotters' beliefs in science and scientists. Similar to what the author of the summary wrote. People are looking for ammunition to fit preconceived ideas, instead of just opening their mind and searching for the truth. To me that is what science is about or should be anyway, a search for the truth without prejudice.
I'm a bit off topic here and rambling, I guess seeing people try to bend and form scientific research to prove their own belief systems has been disturbing me lately. It seems that science is the new religion for many. This new religion's adherents are just as intolerant of other's viewpoints as good old fashioned religions have been.
(B) The claim of "many" is overblown. There are a very very few, compared to the overall number of people that study this. Almost all of them have the distinction of being a member of some religion that have their belief. And few of them seem to even be against evolution per se - they just try to insert other factors *too*, for instance saying "There is evolution BUT specication comes from God". And there is no significant rationale for doing so.
WRT "treated as fact": They are treated as facts because they are facts. There may be other things that influence, yet the *main thrust* of variance in those areas are explained by these cathedrals of knowledge. That's what a scientific theory is, BTW - a cathedral of knowledge that explains variance. It is NOT the same as a hypothesis, even though people tend to abuse the term informally.
Eivind.
Doubting the existence of evolution is like doubting the existence of China: It just shows that you're uninformed.
"Shared genetic material, shared aspects of biochemistry that could be different, shared morphology, etc."
Aren't those the same kinds of similarities between cars that have vastly different designers and designs? You're not proposing that cars are not the product of separate creations just because they have a lot of similarities are you?
Engineering and the Ultimate
Common elements of humans found in rocks. Have we evolved from a common ancestor?
Do rocks regularly make imperfect, self-sustaining copies of themselves?
If not, then your analogy is completely and totally inane.
STOP MISUSING APOSTROPHES, YOU MORONS!!!
Seriously: When it comes to shared ancestry, the evidence is very, very, very strong. There are hundreds of thousands of datapoints. There are an extreme number of predictions that have been done based on this, there are extreme amounts of verification.
You are actually jumping to a conclusion. I'm assuming this isn't malicious - you seem to want to actually get at the real answer - yet when you take the time to actually inspect the evidence around evolution, you'll find that it is confirmed a million ways. As I said in another post: Evolution explains most variation in nature. There may be other sources of variation we do not know of - yet they cannot displace evolution and the data we have around it. Instead, they may be supplementary theories, used *together with* evolution.
This knowledge is sort of like our knowledge of the continents. 500 years ago, we didn't know about more than a couple of continents - the eurasian continent and africa. Now, we know all the continents *and know we know all the continents*. There is sufficient evidence, criss-crossing and linked together, that we can say this as an absolute fact.
There is sufficient evidence of shared ancestry and evolution that we can say this as an absolute fact, too, with similar interlinking.
Eivind.
Doubting the existence of evolution is like doubting the existence of China: It just shows that you're uninformed.
Oh, you were doing so well until that last bit...
Science cannot become 'the new religion for many', intrinsically. Science is "the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment". The very definition of science requires that you must be able to prove and test your statements, in the real world. Its the best 'truth' we've got. You are conflating faith and belief, which are not the same thing.
You are right in this sense only: I am fairly intolerant of unprovable bullshit. Is it really dogmatic to hold your convictions in proportion to your evidence?
If Jesus wants me it knows where to find me.
"Aren't you actually grossly violating that by attempting to bring forth an untruth because you're too lazy to check the evidence?"
I have checked the evidence.
"Evolution and natural selection is the cause of most, if not all, variation in the biological world."
This is simply false. Natural selection has not been able to explain hardly anything. It is simply invoked. Read some biological papers. Whenever something new is found, it is simply listed as "having evolved" without any discussion about how the evolution could even have taken place.
_Most_ of the variation that takes place is the result of Mendellian inheritance, which, by the way, was discovered by a creationist (who used it to argue _against_ transformism).
The environment induces a large part of variance. Scott Gilbert has written about many of these, include variance resulting from an animal sensing predatory animals in the environment, and specifically changing their morphology to account for it. The process of genetic assimilation will make these changes the default morphology even in absence of the predator after a certain number of generations.
Likewise, microbes can change their genome in response to the environment. They can use transposons to activate latent genes, they can induce a highly regulated mutagenesis which produces almost entirely beneficial mutations.
Natural selection explains almost nothing. All natural selection means is that dead things don't reproduce, and sick things don't reproduce well. This is a conservative, not a creative process. And random mutation has too big of a search space to do anything productive. Perhaps you should take a 21st century view of evolution rather than the 1950's version of it you are looking at now.
Please tell me what the evidence is that (a) everything shares a common ancestor, and that (b) random mutation + natural selection is sufficient for creating the diversity that exists today from that common ancestor. If you want to be really adventurous, you can also show how (c) life could have proceeded from non-life.
Also, while we're at it, you could try showing how choice can arise through material mechanisms. If choice can't arise through material mechanisms, then either (a) choice as a real entity doesn't exist, or (b) a material view of origins is insufficient.
Engineering and the Ultimate
Look up the recent publications about alcohol dehydrogenases. What you now mention is a good example of convergent evolution, where the needs of function impose structure. The argument you use to counter my reply in effect proves my point. If you are a believer in intelligent design, please admit to it. But do not bother us here with its flawed arguments. For further discussion everybody is better off reading the judge's dissection of intelligent design in the recent Kansas ruling.
----- One learns to itch where one can scratch.