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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.'"
Which of these cells pinch off to form friggen laser beams?
You're nothing; like me.
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.
Let's see, humans have: sight, sound, smell, taste, touch, pressure, deep pain, surface pain, referred pain, hot, cold, static equilibrium, and dynamic equilibrium. Some might even throw in thirst and hunger.
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.
I can't believe a slashdot poster didn't include spidey in the list.
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
The five senses that humans have are classified as such because they are five distinct ways that we can sense our environment and surroundings. (Some even argue that smell and taste are the same sense because they're both a chemical composition sense.) The ability to sense electrical signals is in every way, shape and form a distinct sense from the five that humans have.
The universe allows only so many senses, because there are only so many ways that one object can make itself "known" to another object (which is exactly what senses are about). Think about it... there's radiation in the electromagnetic spectrum (sight), compression waves (sound), chemical traces (smell and taste), and actual contact (touch). But nature has a few other communication tricks up its sleeve, and electical signals is one of them. The fact that humans can't sense them doesn't mean that it's supernatural.
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.
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.
> 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.
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.