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What Birds See [evolution of the eye]
Scientific American ^ | July 2006 | Timothy H. Goldsmith

Posted on 07/03/2006 10:05:56 AM PDT by doc30

We humans customarily assume that our visual system sits atop a pinnacle of evolutionary success. It enables us to appreciate space in three dimensions, to detect objects from a distance and to move about safely. We are exquisitely able to recognize other individuals and to read their emotions from mere glimpses of their faces. In fact, we are such visual animals that we have difficulty imagining the sensory worlds of creatures whose capacities extend to other realms--a night-hunting bat, for example, that finds small insects by listening to the echoes of its own high-pitched call. Our knowledge of color vision is, quite naturally, based primarily on what humans see: researchers can easily perform experiments on cooperative human subjects to discover, say, what mixtures of colors look the same or different. Although scientists have obtained supporting information from a variety of other species by recording the firing of neurons, we remained unaware until the early 1970s that many vertebrates, mostly animals other than mammals, see colors in a part of the spectrum that is invisible to humans: the near ultraviolet. ...

(Excerpt) Read more at sciam.com ...


TOPICS: Culture/Society
KEYWORDS: bird; creationism; evolution; eye; ignoranttheocrats; kindastupid; ludditefundies; lyingforthelord; paganjunk; pavlovian; roadtohorseshitpaved; saganscience; youngearthcultists
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To: Sentis

Yep, I did - you wrote that Christians were knuckle dragging racists who belong in the Democrat party.

The person you replied to questioned whether white, Creationist Christians should be excluded from Free Republic.

Please recognize that Christians are not knuckle dragging racists, they make strong contributions to Free Republic and to society in general - and that religion/ethics cannot be divorced from politics - the only difference is the ethics to which you subscribe.

That's why we have such interesting discussions on illegal immigration, abortion, euthanasia, welfare, education, land use, you name it.

Blessings,


161 posted on 07/03/2006 3:31:15 PM PDT by Wicket (God bless and protect our troops and God bless America)
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To: doc30

You dirty dog ya. You included "evolution" in the title just to get a bunch of hits, didn't you?

I'll be checking in regularly just to view the carnage.


162 posted on 07/03/2006 3:31:44 PM PDT by saleman
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To: Skooz

I said if you are defending that sort of person that your probably a member of stormfront. If you defend a person that acts like a Nazi on a public forum there is a good chance you are one or am I wrong?

Yes lets see you called me a bigot (or inferred I was a bigot) because the person I was attacking (not you by the way until you defended that person) was doing something you now call ignorant. Three pages ago you were attacking me for calling those people morons now you are calling the same thing ignorant.


Oh and by calling me on "my" bigotry that wasn't even there you were defending the actual bigot (regardless if you want to call it defending him or not). Maybe you should read the post I was responding to before you respond? Hmm that might make you less prone to being called names in the future.


163 posted on 07/03/2006 3:31:46 PM PDT by Sentis (You said the world doesn't need salvation so why do I hear it calling out for a Savior.)
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To: Sentis

Well, we may just be misunderstanding one another. No big deal.

Have a good night.


164 posted on 07/03/2006 3:31:55 PM PDT by Skooz (Chastity prays for me, piety sings...Modesty hides my thighs in her wings...)
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To: bert
To bring the thread current, he would fly into their picture window looking out on the deck. He messed it up pretty good.He did it a lot. Hence retarded as in he wouldn't learn.

Any way, they bought some plastic maple leaves that stick to the window. They emit ultraviolet that looks clear to the human eye. Under certain conditions when viewed from outside they are faintly purple. They stopped the flights into the window immediately!!

I was thinking of that reading your post. Older windows would have no UV absorber, so they would look transparent. But windows with UV reflective (or absorbing) film (used to protect interior contents from UV degradation or bleaching) would appear opaque or only partially transparent to a bird. It would be enough of a visual cue for the bird to avoid flying into it.

165 posted on 07/03/2006 3:34:28 PM PDT by doc30 (Democrats are to morals what and Etch-A-Sketch is to Art.)
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To: Wicket

Your a moroon as Bugs Bunny would say. What a Moroon. I have restated ten time what I said and I said the same thing the first time. Christians that believe that conservatives can only be Christians are knuckle dragging racist idiots. I can add more monikers to them if you like but if you look around alot of Christian I would say most of them dont fit my category. In fact most understand the difference between the words and the ideas of Christian and conservative......do you know the difference?


166 posted on 07/03/2006 3:34:42 PM PDT by Sentis (You said the world doesn't need salvation so why do I hear it calling out for a Savior.)
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To: Sentis
I said if you are defending that sort of person that your probably a member of stormfront. If you defend a person that acts like a Nazi on a public forum there is a good chance you are one or am I wrong?

I defended no one. I merely asked you to explain what you meant. You then went on about knuckle dragging Christians, or whatever. I don't even know who who are saying I am defending. Does this person have a name?

Maybe you should read the post I was responding to before you respond? Hmm that might make you less prone to being called names in the future.

I read every post on the thread. None of them deserved such vile derision from you. And what will make me less prone to being called names in the future is dealing with adults.

167 posted on 07/03/2006 3:35:19 PM PDT by Skooz (Chastity prays for me, piety sings...Modesty hides my thighs in her wings...)
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To: Sentis
The person I was addressing implied that this forum was only for Christians and that to be a Conservative you had to be a Christian.

I have a very conservative co-worker that believes that to be American, one must be both a conservative and a Biblical literalist Christian. THe logic is something like the Founding Fathers were CHristian and the nation was built upon Christian principles. Therefore, to be American, you must be CHristian. Non-christians and Democrats can't be American.

168 posted on 07/03/2006 3:37:34 PM PDT by doc30 (Democrats are to morals what and Etch-A-Sketch is to Art.)
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To: Skooz

Yes and your so above calling people names on this thread my friend. It is a happy thing that your so adult and above that stort of thing, bud.


169 posted on 07/03/2006 3:39:02 PM PDT by Sentis (You said the world doesn't need salvation so why do I hear it calling out for a Savior.)
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To: Sentis

sort of thing even


170 posted on 07/03/2006 3:40:11 PM PDT by Sentis (You said the world doesn't need salvation so why do I hear it calling out for a Savior.)
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To: Skooz; central scrutinizer; Sentis
No, he said specifically that he wanted white Christians who believed in Creation to join the Democrats.

No, he didn't. I understood what he was saying, why can't you?

Let's review:

Central Scrutinizer wrote: Unfortunately, for some, to be conservative, you must be a white christian who believes in creationism, and never ever veers from that.

No thanks.

(Here, CS is stating those that think you have to be a white Christian creationist to be a conservative are jerks. If I'm wrong, CS, please correct me.)

Sentis responds: I am always wishing those same people would go on over to hang with their intellectual equals in the democrat party.

(Here, Sentis is saying that those intolerant jerks that CS was describing should join the dems.)

Your query: You want all white Christians who believe in creation to become Democrats?

And here Sentis clarifies: Nope just the intellectual giants in the Christian camp that confuse conservatism with their religion.

I don't see how you could mistranslate that "nope". Yet you continue to misconstrue Sentis' statement.

171 posted on 07/03/2006 3:56:08 PM PDT by stands2reason (ANAGRAM for the day: Socialist twaddle == Tact is disallowed)
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To: js1138
Color blind people can often distinguish colors better in bright light.
172 posted on 07/03/2006 4:00:51 PM PDT by doc30 (Democrats are to morals what and Etch-A-Sketch is to Art.)
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To: saleman

That, and pinging PH. But this is still a very interesting subject - wondering how other living things perceive the world.


173 posted on 07/03/2006 4:02:57 PM PDT by doc30 (Democrats are to morals what and Etch-A-Sketch is to Art.)
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To: js1138
Color blind people can often distinguish colors better in bright light.

That makes sense. With greater illumination, there may be some enhancement in the stimulation of the photoreceptors, a decrease in the signal-to-noise ratio or even saturation of one receptor compared to the other. All three may affect color contrast. Also, don't forget that color is a matter of perception in the brain and not an actual physical property of a material.

174 posted on 07/03/2006 4:04:44 PM PDT by doc30 (Democrats are to morals what and Etch-A-Sketch is to Art.)
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To: Wicket
Yep, I did - you wrote that Christians were knuckle dragging racists who belong in the Democrat party.

That's BS. Prove it.

The person you replied to questioned whether white, Creationist Christians should be excluded from Free Republic.

Also BS.

175 posted on 07/03/2006 4:04:59 PM PDT by stands2reason (ANAGRAM for the day: Socialist twaddle == Tact is disallowed)
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To: doc30
Also, don't forget that color is a matter of perception in the brain and not an actual physical property of a material.

Color vision in humans is generally studied by having the subject mix three monochromatic (narrow band filtered) color sources to match a pigment sample. That doesn't contradict what you said, but it reduces the effect of learning color names.

176 posted on 07/03/2006 4:08:12 PM PDT by js1138 (Well I say there are some things we don't want to know! Important things!")
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To: js1138
Color vision in humans is generally studied by having the subject mix three monochromatic (narrow band filtered) color sources to match a pigment sample.

You are correct and I'm quite aware of the sciecne behind quantifying color vision in humans. I'm a spectroscopist who had to write software to quantify color, amongst other things, for the business I'm in. It's easy to represent color in a variety of 2 dimensional color coordinate systems like L*a*b* (a*b* being the color portion, L* representing the lightness or darkness of a color). Imagine how much more complicated that would be for a tetrachromatic system? That would be color in 3-dimensional coordinates with a fourth dimension for lightness. Very difficult to mentally visualize. Our color wheel would essentially be a 2D surface in a 3D color space. You would have UV mixed with the other 3 primary colors. So you could have yellow, blue and red, their combinations and then all of those combinations with various amounts of UV. You could have UV+blue as a new color, as well as UV+red and UV+yellow. The vividness of an avian vision system must be incredible. The authors in the article attempted this very thing by estimating the spectral response and luminosity of a given object based on avian photoreceptor sensitivity would have in this color space and see if the birds could distinguish it from other UV-color objects. The theory matched the bird behaviour very well.

Since we lost the color receptors and then gained one back, I wonder if our brains neurologically could process a tetrachromatic color system.

177 posted on 07/03/2006 4:24:16 PM PDT by doc30 (Democrats are to morals what and Etch-A-Sketch is to Art.)
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To: doc30

Entering the twilight zone of pure speculation: humans experience color temperature as a banded gradient. It is fairly easy to demonstrate that the bands of the rainbow have no object reality, and yet we see seven or so fairly distinct bands. If color information is coded as neural firing rates, the bands could be heterodynes.

If we had more color receptors, we might experience more "primary" colors. Do you happen to know how how many rainbow colors are seen by colorblind people? I am a bit embarrassed asking this, because my son is red-green colorblind.


178 posted on 07/03/2006 4:34:22 PM PDT by js1138 (Well I say there are some things we don't want to know! Important things!")
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To: Tokra
You mean like the different bacteria that have evolved to make themselves immune to anti-biotics? The immunity that wasn't in their genetic code before, but is now?

That is nothing more than pharmacodynamic tolerance. Using bacteriological immunity to drugs is a poor example of "evolution". Now if, in response to a large dose of antibiotics one bacteria changed into another type of bacteria altogether then you may have reason to crow.

179 posted on 07/03/2006 4:36:24 PM PDT by Mogollon
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To: Mr. Mojo
Anecdotal post in protest of the crevo argument ;>

Mr. Mojo, I'm near a tidal river in Maine, and we have heaps of Baldies, even a Golden here and there. Probably one of the coolest things I've ever seen was a Baldy figuring out how to get part off a deer carcass airborne. the river was frozen solid, with huge upright slabs of Ice along the shores, heaved up by the tidal action, but the center was glassy and flat.

Game Wardens had thrown a roadkill doe out onto the ice, I estimated that the doe would dress out to around 110 or more. Evidently this Baldy or other critters had been working the carcass for a while before we got there

The Baldy was working it over hard, concentrating on the area just fore of the hindquarters. I assumed he was just going for sweet meats.

I didn't know it at the time but the Baldy was working a plan. After about 10 or 15 minutes of this. He took a hop and circled, then hit it from a different angle in the same spot. With lots of strenuous looking bites and turns.

What he had done was sever the area between the last vertebrae and the pelvic area. He now had two sections.

He took the head and the trunk (sans front-quarters)which was striped down to straps and a stem of spine. It couldn't have weighed much but it sure looked like a lot of deer to me.

The Baldy sat on the head, got a good grip, then with a hopping and flapping motion he wrestled the deer over to the smooth part of the ice, towards the glassy center and he started flapping, -the carcass started sliding across the ice.

I was with a friend, we both said: "No way"...

He flapped, gained speed, it took way more than 200 yards, but he started to turn into the wind at a wide bend and he got airborne, made it over the treeline and out of site.

Common knowledge is that they can lift about half their bodyweight. I would have estimated the piece of carcass to be 10 Lbs or more, -but I know the bird wasn't more than 15 Lbs, so say it was 7 Lbs of carcass. It was still an awesome sight.

I wonder if the factoid about how much a Baldy can carry in flight does not take into account the scenario of an icy-river with just the right winds.

180 posted on 07/03/2006 4:49:25 PM PDT by Capn TrVth
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