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We evolved to see light, we could have evolved to see sound?

by Avichal
Tags: evolved, light, sound
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Avichal
#1
Feb26-13, 09:45 AM
P: 283
Living things have eyes to respond to light coming from the sun. So the brain has evolved to interpret light as colors and hence picture the world.

Do you think living things could have evolved to see sound. More vibration corresponding to different color, less vibration corresponding to other.
Although seeing light is much better than seeing sound but this is possible right - seeing sound?
I am not saying that seeing sound should have occurred but just asking whether such a natural phenomena could happen

Hope question makes sense. Thank You!
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thorium1010
#2
Feb26-13, 10:08 AM
P: 200
Quote Quote by Avichal View Post
Living things have eyes to respond to light coming from the sun. So the brain has evolved to interpret light as colors and hence picture the world.

Do you think living things could have evolved to see sound. More vibration corresponding to different color, less vibration corresponding to other.
Although seeing light is much better than seeing sound but this is possible right - seeing sound?
I am not saying that seeing sound should have occurred but just asking whether such a natural phenomena could happen

Hope question makes sense. Thank You!
Maybe you are looking for something called perception rather than seeing. We do not see hot or cold same way as we do not see vibration.

http://en.wikipedia.org/wiki/Perception

Have you ever read about bats, they use a kind of sonar to help them in flight.

http://en.wikipedia.org/wiki/Bat#Echolocation
Darwin123
#3
Feb26-13, 10:13 AM
P: 741
Quote Quote by Avichal View Post
Living things have eyes to respond to light coming from the sun. So the brain has evolved to interpret light as colors and hence picture the world.

Do you think living things could have evolved to see sound. More vibration corresponding to different color, less vibration corresponding to other.
Although seeing light is much better than seeing sound but this is possible right - seeing sound?
I am not saying that seeing sound should have occurred but just asking whether such a natural phenomena could happen

Hope question makes sense. Thank You!
I am not sure what you mean by "seeing". The definition of seeing is the sensing of light.

I conjecture that you mean imaging. Could sound be used as a method of determining the shape and angular size of an object. By angular size, I mean the apparent size which decreases with distance.

Human beings can image distant objects with light fairly precisely. The have thousands of sensing cells on their retinas and a lens. However, no such system exists with the ears. You can not estimate a shape by hearing it. So humans have the ability to image light, but they can't image sound. Given a physiology and an anatomy close to the modern primate form, I don't think there is a much of a potential to image sound.

Some other animals have the ability to image sound. Dolphins and bats are famous for their sonar. They give off sound waves which reflect off of an objects. From the sound that comes back, they can estimate the rough shape and angular size of an object. However, their ability to determine shape with sound is limited relative to their ability to determine shape with light.

One thing that limits image resolution is the wavelength. Whatever wave an animal uses to determine shape, the resolution is limited by the wavelength that they can hear. The wavelength can't be longer than the length of the object. I don't know the note scale very well. However, most of the notes that humans hear have wavelengths from a few inches to feet long even if they had a special organ to image the sound.

Dolphins and bats can make and hear sounds with very short wavelengths. So the potential for imaging such high pitched sound is very great.

Both animals have special features that image sound. Both of them have skulls that collimate the sound that they give off. Other features they use are specially shaped jaws and a special features in their brains. They have special organs for making sounds. Bats use highly developed vocal cords. Dolphins use specially shaped nasal cavities to basically "hum" in high pitch. I don't know if you consider their ability as "seeing" sound. However, they do sense what some scientists call "images" from sound.

Avichal
#4
Feb26-13, 10:22 AM
P: 283
We evolved to see light, we could have evolved to see sound?

Oh thanks for telling me about bats and dolphins - read them up on wikipedia.
So I suppose they came up with these abilities because they usually stay in dark. So they don't have light to help them detect thing around them. So they use sound to "see" things.

Anyways thanks a lot. I'll read more about these animals now.
Darwin123
#5
Feb26-13, 06:50 PM
P: 741
Quote Quote by Avichal View Post
Oh thanks for telling me about bats and dolphins - read them up on wikipedia.
So I suppose they came up with these abilities because they usually stay in dark. So they don't have light to help them detect thing around them. So they use sound to "see" things.
This is probably true for bats. Bats rest and take care of off spring in the depths of caves. Natural caves are completely dark. Most bats hunt for food at night. The night sky is not completely dark all the time. There is no way a bat can see in a cave.

Bats do use their eyes to see. Bats are not blind. Most of them have good eyes which they use when light is available. The moon provides some light during part of the month. Bats like to hunt at the twilight hours, where some sunlight from below the horizon is scattered by atmospheric particles. However, the sky is dark enough even at that time to cause problem in hunting for animals that depend on sight alone.


I don't think that is strictly true for dolphins. Most dolphins hunt close enough to the surface that sunlight reaches them. They may visit the bottom of the sea, but they don't live there. Furthermore, dolphins are diurnal. They prefer to move during the day. So sight is still useful for most dolphins.

It should be pointed out that all extant toothed whales have sonar. Dolphins are just one type of toothed whale. A dolphin by some definitions is just a small toothed whale of any species.

The most famous type of dolphin, Tursiops truncatus, lives in lots of different environments. Different families of Tursiops truncatus not only live in separate environments, they have a family "culture" that specializes in hunting in these separate environments. So one could probably find a number of uses for sonar just in this one species alone. However, there are a lot of toothed whales who are not Tursiops truncatus. So I wouldn't make a broad statement on why dolphins have sonar.

There are many species of of toothed whales which have differing lifestyles. The reason for using sonar is almost as varied as their life styles. Some toothed whales do hunt at great depths where the sunlight doesn't reach. However, I don't think most of them hunt in the darkest depths of the ocean.

Very few dolphin species are blind. The ones that are blind live in muddy rivers. Mud scatters light, there by scrambling the light-images. I think light gets down there, even through mud, but images are blurry. So sight isn't very useful, even if there is light.

Porpoises live in estuaries and bays. The water in these types of water ways is sometimes muddy and sometimes not muddy. Porpoises have both sonar and sight for obvious reasons.

One reason that oceanic toothed whales may have evolved sonar is because water attenuates light over over large distances. Particles in the water (algae, etc.) scatter light and scramble images. So some toothed whales probably need the sonar to hunt over large distances.

I don't think the sonar of a toothed whale is useful to find things out of water. There is an impedance mismatch between air and water that makes sound bounce off the surface. This reflection moves in both directions. So for a dolphin underwater to image above water, it needs sight. Not sonar.

Narwhals are strange looking dolphins that hunt underneath arctic ice. So they do hunt in darkness much of the time. However, they do get out from under there every summer.

I think that the sonar capability originated in the common ancestors of all toothed whales that live about 30 million years ago. My guess is that the common ancestor of all toothed whales probably hunted near the bottom of the ocean. Whatever the original reason, sonar is used for a lot of different reasons for a lot of difference species. There are many species of toothed whale with many different uses for sonar.
Borek
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Feb27-13, 01:41 AM
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Quote Quote by Darwin123 View Post
One reason that oceanic toothed whales may have evolved sonar is because water attenuates light over over large distances. Particles in the water (algae, etc.) scatter light and scramble images.
Even sea water, especially in the areas rich in food, is murky, which means sight is not of much use (as opposed to echolocation).

Narwhals are strange looking dolphins that hunt underneath arctic ice. So they do hunt in darkness much of the time.
As far as I know from my diving friends, it is not that dark under the ice, at least as long as it is not covered with a thick layer of snow.
Darwin123
#7
Feb27-13, 08:58 AM
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Quote Quote by Borek View Post
Even sea water, especially in the areas rich in food, is murky, which means sight is not of much use (as opposed to echolocation).



As far as I know from my diving friends, it is not that dark under the ice, at least as long as it is not covered with a thick layer of snow.
Thank you! I didn't know that!

How often is the ice not covered in thick snow?
Borek
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Feb27-13, 09:33 AM
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Quote Quote by Darwin123 View Post
How often is the ice not covered in thick snow?
Apparently often enough - some of the Attenborough movies do have great underice sequences shot without using artificial light.
chemisttree
#9
Feb27-13, 06:42 PM
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Perhaps your question should be, "Why haven't we evolved the ability to control synesthesia?"

I would think that the ability to control it would be a great advantage but since we can't, I guess I'm wrong.
madness
#10
Feb28-13, 05:48 AM
P: 611
I see it as more of a philosophical question - why does vision have such a different subjective experience to hearing? In principle, it could have been that the subjective nature of the two experiences had been reversed, so that we could "see sound", but it isn't. I don't think we have any good scientific answers to these kind of questions yet.
Ryan_m_b
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Feb28-13, 08:01 AM
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Quote Quote by madness View Post
I see it as more of a philosophical question - why does vision have such a different subjective experience to hearing? In principle, it could have been that the subjective nature of the two experiences had been reversed, so that we could "see sound", but it isn't. I don't think we have any good scientific answers to these kind of questions yet.
It's not just a philosophical question but you're right that neuroscience can't approach an answer at this time. It is essentially the qualia problem, why is subjective experience as it is? Studying synesthesia might give more insight to this problem as in severe cases you can get very strong, non typical associations.

On a related note I do remember reading a paper years ago that reported ectopic photoreceptors in drosophila melanogaster connecting to other parts of the central nervous system, seemingly functionary. In other words they could potentialy detect light with other senses. Ill see if I can find it.
chemisttree
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Feb28-13, 04:29 PM
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Interesting, Ryan. I read somewhere that as many as 1 in 23 people have some form of synesthesia and it's a heritable trait. Perhaps elsewhere in the animal kingdom, vision and hearing are linked with other senses but we humans are currently evolving away from that synesthesia?


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