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Strange Range!!!

Debate and discussion of any biological questions not pertaining to a particular topic.

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Strange Range!!!

Postby 2810712 » Fri Mar 03, 2006 4:29 pm

LEt the Focus shift on Light!
We can sense a light of definite wavelength range with our eyes...diff. organisms have different ranges...plants also have some definite range of more active photosynthesis i think...
I know stories about why plants had red as the most responded wavelength for photosynthesis. It says that as the early deep water phototrophs could get red light more than the others... but after some superficial species developed...the blue part also got rised for its response...
i doubt the origin of photosynthesis in underwater species and not supeficial ones...

see amaizingly ultraviolet or infrared are mostly not used... ultraviolet can affect protein stability relatively more harsh way and infrared give relatively less energy...

I wonder how our ears are developed with its ranges of sound frequencies...

I curious about explanations of human and animal sensory ranges...


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Postby sebast18 » Fri Mar 17, 2006 7:52 pm

Obviously human ears are likely to have evolved like our own body, by adapting to our needs. The ears developpement is focused on frequencies that may announce a danger or any other useful information. Nature majorily produces a specific range of frequencies that are useful to our perception of the world around us. This is the reason we dont ear very low frequencies like elephants. They hear those frequencies because it is the way they communicate over great distances (low frequencies travels a longer distance). So the elephants thats are looking for food in the savana can find their clan. At the oppposite the bat hears high-frequency sounds so good, it can litterally see the world through its ears. A bat can sense a humain hair dropped 1 meter in front of it, flying at full-speed in a pitch-black night. Well, humans are very social animals so they don't really need to hear low frequencies, could be handful but its not necessary to the survival of the specie. Humans are diurnal, we are active during the day so we don't need the bat's system, again, it could be cool but not necessary... We just hear what's useful to us :P
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Postby MrMistery » Sat Mar 18, 2006 8:00 pm

Photosynthesis discussion, cool :roll:
Ok, now, first of all you can not use UV light for photosynthesis, as if you were to live in a place with enough of it to live of photosynthesis from UV light, you would fry regardless if you are a bacteria or a sequoia.
Now, about IR. Bacteria(Chlorobium, Cromatium) can use IR light for photosynthesis because of their bacterichorophil. It is not yet known if clorophil evolved from bacteriochrolophil or they evolved from a common ancestor. Given the difference in absorbtion spectrum of IR light, the second hypothesis seems to gain an edge. But serious research needs to be carried out.
About visible absorbtion specter:
First of all you need to understand light. Blue light is the type of light with the smallest number of photons, but they each have immense energy. At the opposite end, red light has a lot of photons but with very few energy. It is because of this energy that blue light penetrated deeper into water.
The species of algae that live at the surface(Green algae) and terrestrial plants, have evolved to use red light, as it has the biggest number of photons. Given the mechanism of photosynthesis, you extract the same amount of energy from any photon, so the only thing that matters is photon number. A scale of measurement, called photosynthetic photon flax density has been developed for this measurement.
On the other hand, algae that live in deep water, where there simply is no light, use their little carotenoid pigment called phycoeritrine, and carry out quite an efficient photosynthesis in blue and green light: adaptation to the environment.

About animal ranges... Well, unfortunately it depends on the animal, cause some ar color blind, some are totally blind and some have an incredible sense of sight. Same for ears and every other sense...
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
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Postby pankaaj » Tue Mar 21, 2006 6:48 am

sebast18 wrote:Obviously human ears are likely to have evolved like our own body, by adapting to our needs. The ears developpement is focused on frequencies that may announce a danger or any other useful information. Nature majorily produces a specific range of frequencies that are useful to our perception of the world around us. This is the reason we dont ear very low frequencies like elephants. They hear those frequencies because it is the way they communicate over great distances (low frequencies travels a longer distance). So the elephants thats are looking for food in the savana can find their clan. At the oppposite the bat hears high-frequency sounds so good, it can litterally see the world through its ears. A bat can sense a humain hair dropped 1 meter in front of it, flying at full-speed in a pitch-black night. Well, humans are very social animals so they don't really need to hear low frequencies, could be handful but its not necessary to the survival of the specie. Humans are diurnal, we are active during the day so we don't need the bat's system, again, it could be cool but not necessary... We just hear what's useful to us :P

How were elephant's & bat's responses to different level of frequencies evovled?
And why we need ear extencively?
i mean to say that the language originated not a long back ago !
it is obvious that wild man should need good hearing capacity. But then why they can't hear IS & US frequencies?
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Postby 2810712 » Sat Apr 01, 2006 2:38 pm

Sorry for late resonse... THANKS...

Now i didn't get why is flux density of red light photon is higher than lower WAVELengths... and how can u achieve a generalization for it...[ in terms of relative flux densities..?]

ANd how we say that blue and green reach the 'bottom' algae... red travels most deep due to lower refracting index of h2o for red than other visible wavelengths... and infrared would have lesser energy...[ obviously in evolution just one reason isn't there...]
Other things i got...









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