96 percent of vertebrates -- including humans -- descended from ancestor with sixth sense

October 11, 2011 By Krishna Ramanujan, Cornell University
A juvenile paddlefish filter feeds in a tank at Shedd Aquarium, Chicago. Image: Jon Weinstein and Lance Grande, Field Museum of Natural History

(PhysOrg.com) -- People experience the world through five senses but sharks, paddlefishes and certain other aquatic vertebrates have a sixth sense: They can detect weak electrical fields in the water and use this information to detect prey, communicate and orient themselves.

A study in the Oct. 11 issue of Nature Communications that caps more than 25 years of work finds that the vast majority of vertebrates – some 30,000 species of land animals (including humans) and a roughly equal number of ray-finned fishes – descended from a common ancestor that had a well-developed electroreceptive system.

This ancestor was probably a predatory marine fish with good eyesight, jaws and teeth and a lateral line system for detecting water movements, visible as a stripe along the flank of most fishes. It lived around 500 million years ago. The vast majority of the approximately 65,000 living vertebrate species are its descendants.

"This study caps questions in developmental and evolutionary biology, popularly called 'evo-devo,' that I've been interested in for 35 years," said Willy Bemis, Cornell professor of ecology and evolutionary biology and a senior author of the paper. Melinda Modrell, a neuroscientist at the University of Cambridge who did the molecular analysis, is the paper's lead author.

Hundreds of millions of years ago, there was a major split in the evolutionary tree of vertebrates. One lineage led to the ray-finned fishes, or actinopterygians, and the other to lobe-finned fishes, or sarcopterygians; the latter gave rise to land vertebrates, Bemis explained. Some land vertebrates, including such salamanders as the Mexican axolotl, have electroreception and, until now, offered the best-studied model for early development of this sensory system. As part of changes related to terrestrial life, the lineage leading to reptiles, birds and mammals lost electrosense as well as the lateral line.

A scanning electron micrograph of the head of developing paddlefish shows pores of the lateral line and electroreceptive organs. Image: Willy Bemis

Some ray-finned fishes – including paddlefishes and sturgeons – retained these receptors in the skin of their heads. With as many as 70,000 electroreceptors in its paddle-shaped snout and skin of the head, the North American paddlefish has the most extensive electrosensory array of any living animal, Bemis said.

Until now, it was unclear whether these organs in different groups were evolutionarily and developmentally the same.

Using the Mexican axolotl as a model to represent the evolutionary lineage leading to land animals, and paddlefish as a model for the branch leading to ray-finned fishes, the researchers found that electrosensors develop in precisely the same pattern from the same embryonic tissue in the developing skin, confirming that this is an ancient sensory system.

The researchers also found that the electrosensory organs develop immediately adjacent to the lateral line, providing compelling evidence "that these two sensory systems share a common evolutionary heritage," said Bemis.

Researchers can now build a picture of what the common ancestor of these two lineages looked like and better link the sensory worlds of living and fossil animals, Bemis said.

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JRDarby
3 / 5 (2) Oct 11, 2011
So the questions this poses are: to what degree, if any, do humans still possess an EMF-sensitive perceptual system? how does this work? does it have an effect on day-to-day activities? can we be made aware of this to the extent that we're able to use it in the same way we use our eyes or nose (assuming this still exists in humans)? and how do we find all this out?
PaulRC
3.7 / 5 (3) Oct 11, 2011
hmmm, ninja can supposedly train themselves to see in the dark, gonna have to check out Naruto wiki to learn how to train my 'Byakugan'. lol

Seriously, if such a sense still exists in some humans, could that explain eastern philosophy about chakra? Anatomy shows there are no physical structures to match, but what about electric field/average electric field. Doubt it myself, but a visual 3d electric field camera picture of the human bodies field would be interesting nevertheless, and it might be useful in medical imaging/diagnostics/disease detection.
MentalHealthNut
5 / 5 (6) Oct 11, 2011
I can assume many land animals evolved away from this sense because of the resistance of electricity in the air as opposed to the abundant conductivity of water.
JRDarby
1 / 5 (1) Oct 11, 2011
Good point, MHN. I tried looking for more evidence of land-dwelling EMF-sensing animals and I couldn't find any.

For others: http://en.wikiped...eception
emsquared
5 / 5 (2) Oct 11, 2011
I see electric people...

I tried looking for more evidence of land-dwelling EMF-sensing animals and I couldn't find any.

What about migratory birds and homing pigeons, etc.? Not the same of course, but could be an adaptation of the sensory mechanism? Or perhaps more likely a re-emergence and re-purposing of a biological mechanism that faded to almost nothing?
jimbo92107
5 / 5 (3) Oct 11, 2011
Some people seem to have an innate sense of compass direction. Maybe they're tapping into the old lateral line!
YummyFur
1 / 5 (1) Oct 11, 2011
@emsquared, it is sort of the same isn't it since the magnetic field detected by birds is an aspect of the electric field.
Honor
not rated yet Oct 11, 2011
you can always sense when the tv is turned on. usually only in old crts
FainAvis
not rated yet Oct 11, 2011
Is that why I'm ticklish? Do I still have the lateral line sensitivity?
Cynical1
1 / 5 (1) Oct 11, 2011
vestigial lateral line remnant is what gives you the "willies" in a dark room just before the vampire bites ya...
kaasinees
2.1 / 5 (9) Oct 11, 2011
What about our organs? Maybe we do not have specialized organs, but our organs might have the ability to sense electric fields? It is logical that our brains can be influenced by outside electric fields, or our organs can send impulses to our brains when an electric field hits. Has there ever been research that it is lack of gravity or electric fields that causes tissue/bone loss.
Argiod
1.8 / 5 (4) Oct 11, 2011
A friend of mine told me years ago that the neurons at the cortex of the human brain are like di-pole antennae, one centimeter long. This would suggest we can transmit and receive electromagnetic signals if they are the length, or a harmonic, of this length; with normal variation among people, of course. This would lend credence to telepathy and other psychic phenomenon, including unconscious communication with animals of different orders than ourselves.

Of course, this is just my opinion; I could be wrong.
JRDarby
1 / 5 (1) Oct 11, 2011
That is very interesting, Argiod. I just did a cursory Google search for information on the neurons you mentioned and I couldn't find anything. Do you have any information you could give me? (I don't know how the neuron would be one whole centimeter long, or how it would act as a dipole antenna.)
jsa09
2.3 / 5 (3) Oct 11, 2011
5 senses? I don't think so

1 sight
2 sound
3 touch
4 taste
5 smell
6 heat

So I don't know about the rest of you but I have 6 senses already.

7 could be a sense of direction that some people have more than others.
RobertKarlStonjek
3.7 / 5 (6) Oct 11, 2011
Humans have far more than six senses ~ we have six major sensory organs (for external sensory information). The skin is capable of a range of sensory stimulus including heat, vibration, wetness, texture (the haptic sense is quite complex) and so on.

But there is other sense information which we don't use, partly because we are not exposed to it through the critical period during maturation (if your eyes were covered during maturation, say via congenital cataracts, and you gained sight in maturity, you would not be able to use sight for judging distance, recognising objects etc without many years of practice and training). These include air pressure via the carotid sinus, electrostatic build-up via the hair and probably air moisture, the information you'd need if you lived out in the open and needed to know short term weather information such as the approach of a storm (pressure change) or lightening (electrostatic build-up).
Jotaf
3.7 / 5 (3) Oct 11, 2011
Jsa09, come on stop trolling, heat belongs to the touch sense :P
Anyway, it would be cool to have a line of electroreceptors. I doubt we have any vestigial traces of that, it would be hard to miss since human physiology is very well studied. Some or most of the genes may lie there dormant, though. This is really interesting stuff!
Graeme
not rated yet Oct 11, 2011
Platypus has electroreceptors on its snout. Because such a diverse range of animals have the receptors, could the organs be hiding in many other vertebrates? Perhaps they only function while the animal is in a watery environment, such as in the egg or womb.
barakn
5 / 5 (3) Oct 12, 2011
neurons at the cortex of the human brain are like di-pole antennae, one centimeter long

... surrounded by millions of other almost identical dipoles oriented in similar directions, efficiently absorbing the electromagnetic signals.
ffrankblu
1 / 5 (1) Oct 12, 2011
I dream of electric sheep,jk,but sometimes I can see what look like little electric particles floating around.
Ojorf
2.1 / 5 (7) Oct 12, 2011
Why is the sense of balance and acceleration never included with the list of senses?
Parsec
2.5 / 5 (2) Oct 12, 2011
Some people seem to have an innate sense of compass direction. Maybe they're tapping into the old lateral line!

There are languages where the direction words refer to absolute directions. You wouldn't say that the fork is to the top of the plate for example, you would say the fork is on the north side. Every person speaking that language can detect true north (or any direction) from a very young age.
sherriffwoody
3 / 5 (2) Oct 12, 2011
Not to mention the sense between our legs
kaasinees
1.4 / 5 (9) Oct 12, 2011
taste is a combo of touch and smell. so not really a sense.

ojorf has a point (balance and accel is from the same organs) but this can be arguably go under the touch sense.
ronald_g_richard
not rated yet Oct 12, 2011
I dream of electric sheep,jk,but sometimes I can see what look like little electric particles floating around.


That happens to me as well. I did a little bit of snooping at some point and found the cause of this, I just cant remember. I think it has something to do with blood pressure/oxygen. My memory sucks.
tkjtkj
2 / 5 (1) Oct 12, 2011
5 senses? I don't think so

1 sight
2 sound
3 touch
4 taste
5 smell
6 heat

So I don't know about the rest of you but I have 6 senses already.

7 could be a sense of direction that some people have more than others.


Surely the sense of 'pain' gives at least as much important info about our environment as #1 thru #6 ! This would make 'electro-sensory' sensitivity #8

BTW, with ref to the pic allegedly showing 'pores' .. :
"A scanning electron micrograph of the head of developing paddlefish shows pores of the lateral line and electroreceptive organs. Image: Willy Bemis"

I do wish the photographer would point out the pores: i just dont see any thing there resembling such a feature.
Skultch
2.3 / 5 (3) Oct 12, 2011
5 senses? I don't think so

1 sight
2 sound
3 touch
4 taste
5 smell
6 heat

So I don't know about the rest of you but I have 6 senses already.

7 could be a sense of direction that some people have more than others.


I don't consider "sense of direction" an actual sense. It's just not a direct response from a single outside stimulus; it emerges from the analysis of multiple senses. If you want to call that a sense, you should also consider empathy a sense.

That said, you are absolutely right we have more than 5 senses. Touch is actually a combination of at least 3: pain, pressure, and heat. We also have a sense of acceleration, which is responsible for the senses of balance and vibration.

These are all senses just as much as sight is. We also have multiple internal senses.
http://en.wikipedia.org/wiki/Sense#Other_internal_senses
Limiting the definition of the word sense to the more obvious 5 is a mistake, IMO. It limits a child's understanding of human ability.
physpuppy
not rated yet Oct 12, 2011
@ronald_g_richard & @ ffrankblu : The stuff you see dancing in your line of vision has nothing to do with extra senses: you probably see it with more acuity when viewing a bright object: the long things that are just floating around are called - eh - floaters - they're stuff in the liquid of the eye. The things that you might see that are moving in a somewhat coordinated manner is from the blood supply to the retina which is in front of the retina.
jsa09
1 / 5 (1) Oct 13, 2011
@ skultch I tend to agree.

I know a lot of people put down heat sense as part of touch but I think that is ridiculous, especially as we feel heat from a great distance unlimited and feel touch directly from contact.

Should it is in the skin but I do not believe that it is the same sensors as the touch sensors. Pain is not actually a sense as it is merely an interpretation of a sense or a warning of overload.

Taste and smell seem to be very closely related yet are counted separately so saying sense of heat source from yards away can be lumped in with sense of touch that has to make contact is ludicrous. And yet this happens.

Balance and pressure may well be related in some way and perhaps can be dragged back into a sense of touch. But the sense organs most sensitive to changes in pressure are used mostly for hearing and yet changes of pressure makes no sound.
Skultch
not rated yet Oct 18, 2011
does anyone else find it amusing that some people downvote, but don't comment on that thread at all? it's so strange and funny. i don't quite get it.
Cynical1
1 / 5 (2) Oct 18, 2011
What sense is in use when you stand next to a high voltage line and can feel the elctricity?
Cynical1
1 / 5 (2) Oct 19, 2011
What is causing the hairs to stand up? A reaction to a very strong, therefore potentially dangerous electric field?

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