Study Confirms: Bacteria Have Ability to See Objects "In Basically The Same Way That We Do"

a reply to: TerryDon79

You are a big boy
Nothing I Say could help

originally posted by: Bedlam

Plants don't have brains but do the same sort of thing, only more slowly.

Phototaxis is a nice bit of feedback control, but doesn't imply intelligence or judgement.

Right, but plant's don't employ rudimentary eye sight like these bacteria have been discovered to do.

And the researchers already knew about phototaxis when they conducted the study. What they found was that the bacteria can actually see, just at a much lower resolution than humans.

originally posted by: Bedlam
Slime isn't "seeing" the way you do, either. It's looking for the direction the light's coming from.

Yes, the slime is seeing. That's the point of the entire study.

And how can they not "see", but still be able "look" for light?

originally posted by: Astyanax
Amazing. But please note that the ‘eye’ and the bacterium are one and the same thing. From the linked paper:

Spherical cyanobacteria are probably the world’s smallest and oldest example of a camera eye.

It isn’t that these bacteria have eyes. The are eyes.

Yes, exactly right. They are microscopic eyes.

Eyes are only ever used for seeing.

originally posted by: AstyanaxThe fact that some bacteria are photosensitive — that is, ‘have sight’ — is common knowledge.

No, not quite. Phototaxis is common knowledge, yes, but the realization that these particular cyanobacteria can actually see the light is what's being highlighted in this study. That was not common knowledge previous to this.

Phototaxis is not the same as seeing.

a reply to: Astyanax

originally posted by: Astyanax
a reply to: Tiamat384

correct me if I'm wrong, but are you suggesting that they can only see where there is light rather than what the OP is saying that they can see as humans do, but at a lower resolution?

They don’t have brains, so it would be absolutely impossible to build up a complex visual picture of the world.

Perhaps not "complex" as to the visual details like we can, but they are seeing. The scientists themselves who worked on this study are saying that, explicitly.

Mullineaux and his team ran a simulation that calculates the bacterial resolution should be enough for Synechocystis to pick out the outline of head and shoulders bending over them.

Not that the bacteria would know what it is looking at

originally posted by: Bedlam

Bacteria do it faster. But the big difference is, instead of scattering photoreceptors all over, the bacteria does it more efficiently by using a lens and a matrix of receptors. That's different. But it's still a phototaxis. You could build a simulator with relays and photocells that would do the same.

I'm not sure if you read the study or not, but it's always been phototaxis. Plants utilize this differently than the bacteria do. Bacteria do it by seeing the light, not sensing it. That is the point here. As far as I know, plants do not and can not see or make out any kind of visual image. These bacteria can because they are actually micro lenses, employing micro-optics, in essence just like mini eye balls!

originally posted by: Bedlam
Here's another thing they do - the bacteria is covered with little chemical receptors, and it can look for gradients of chemical concentration by comparing the number of receptors that are set off from one end to the other. Some chemicals it will run toward, others, it will run away from. In it's own way, the chemotaxis system is more cool. YMMV.

I actually think it's way cooler that bacteria can actually see things, and that these little critters might be the original eye ball.

originally posted by: PhotonEffect

originally posted by: Bedlam
Slime isn't "seeing" the way you do, either. It's looking for the direction the light's coming from.

Yes, the slime is seeing. That's the point of the entire study.

And how can they not "see", but still be able "look" for light?

Seeing implies perception.

The little buggers are putting all their phototaxis sensors on one plane, which is nice. But there's nothing processing the image except cilia.

originally posted by: PhotonEffect
These bacteria can because they are actually micro lenses, employing micro-optics, in essence just like mini eye balls!

If they don't do this, they can't get enough separation to do phototaxis the way a plant does. It's a somewhat more complex way to do phototaxis, as you will find out if you skip the magazine article and read the paper.

originally posted by: Bedlam

Seeing implies perception.

It does, doesn't it.

originally posted by: Bedlam
If they don't do this, they can't get enough separation to do phototaxis the way a plant does. It's a somewhat more complex way to do phototaxis, as you will find out if you skip the magazine article and read the paper.

I read it a few times.
I mean the term " micro-optics" is right in the title. And the abstract doesn't seem to beat around the bush either:

Bacterial phototaxis was first recognized over a century ago, but the method by which such small cells can sense the direction of illumination has remained puzzling. The unicellular cyanobacterium Synechocystis sp. PCC 6803 moves with Type IV pili and measures light intensity and color with a range of photoreceptors. Here, we show that individual Synechocystis cells do not respond to a spatiotemporal gradient in light intensity, but rather they directly and accurately sense the position of a light source. We show that directional light sensing is possible because Synechocystis cells act as spherical microlenses, allowing the cell to see a light source and move towards it. A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot. Spherical cyanobacteria are probably the world’s smallest and oldest example of a camera eye.

elifesciences.org...

originally posted by: PhotonEffect
I read it a few times.
I mean the term " micro-optics" is right in the title.

No-one's saying it's not "micro optics".

And the abstract doesn't seem to beat around the bush either:

Bacterial phototaxis was first recognized over a century ago, but the method by which such small cells can sense the direction of illumination has remained puzzling. ...A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot.

No, it doesn't. And what it's telling you is that it's a very nice example of phototaxis, using the bacterium's cytoplasm as a lens. Not visual perception.

S&F to keep track of this. Thanks for posting, great find!

originally posted by: Bedlam

Bacterial phototaxis was first recognized over a century ago, but the method by which such small cells can sense the direction of illumination has remained puzzling. ...A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot.

No, it doesn't. And what it's telling you is that it's a very nice example of phototaxis, using the bacterium's cytoplasm as a lens. Not visual perception.

I'm sorry, but that's not what the abstract is telling us. I think your edit is causing some obfuscation of the point.

You keep referring to the phototaxis, or the actual movement towards a light source (see bold). This study, once again, has already taken this phenomenon into account. The novelty it has revealed is how the phototaxis is triggered in these bacteria. It is triggered from direct visualization of a light source. It's all right there.

No one has ever considered this before because no one expected that bacteria could see. But guess what. They can. The movement is not a "random walk" to or away from the source. It's direct and deliberate.