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Author Topic:   Silly Design Institute: Let's discuss BOTH sides of the Design Controversy...
TimChase
Inactive Member


Message 42 of 219 (263708)
11-28-2005 8:59 AM
Reply to: Message 4 by RAZD
09-17-2005 9:04 PM


Re: Investigator: Eye's Silly Design (paper #1)
There is one species of crustacean, privileges over all other known sighted organisms with eight different pigments for vision, and thus apparently the ability to see eight different primary colors.

Please see:

Stomatopod Biology
http://www.blueboard.com/mantis/bio/vision.htm

Of course, what I find most interesting is the fact that the different versions of the same gene are used in the marking where the drosophilia (eyeless), the mouse (small eye -- which in mice control the size), and the human (aniridia) will have eyes form, such that, for example, if your take the mouse small gene and substitute it for the drosophilia's, it will perform the same function as the drosophilia's eyeless gene -- and given these homologies, whereas it seemed at one time that vision had been invented about times in the history of life, apparently at the genetic level, it was invented only once.


This message is a reply to:
 Message 4 by RAZD, posted 09-17-2005 9:04 PM RAZD has responded

Replies to this message:
 Message 43 by jar, posted 11-28-2005 4:06 PM TimChase has responded
 Message 44 by RAZD, posted 11-28-2005 6:11 PM TimChase has responded

  
TimChase
Inactive Member


Message 45 of 219 (263869)
11-28-2005 6:13 PM
Reply to: Message 43 by jar
11-28-2005 4:06 PM


Re: Box Jellyfish
Specialization of eyes in the same organism? This sounds like a job for Evo Devo!

Haven't had the chance to read the article as of yet, but you might want to try:

Cubozoan jellyfish: an Evo/Devo model for eyes and other
sensory systems
by JORAM PIATIGORSKY and ZBYNEK KOZMIK
Int. J. Dev. Biol. 48: 719-729 (2004)
doi: 10.1387/ijdb.041851jp
http://www.ijdb.ehu.es/ijdb200448089/ft719.pdf


This message is a reply to:
 Message 43 by jar, posted 11-28-2005 4:06 PM jar has responded

Replies to this message:
 Message 47 by RAZD, posted 11-28-2005 6:21 PM TimChase has responded
 Message 49 by jar, posted 11-28-2005 6:36 PM TimChase has responded

  
TimChase
Inactive Member


Message 48 of 219 (263872)
11-28-2005 6:24 PM
Reply to: Message 44 by RAZD
11-28-2005 6:11 PM


Re: Investigator: Eye's Silly Design (paper #1)
... whereas it seemed at one time that vision had been invented about {*} times in the history of life, apparently at the genetic level, it was invented only once.

Couldn't that just be the gene for light sensitivity from which all other eyes developed? The most primitive level of sight, but also most likely for the most primitive of multicell life forms, to regulate life to the rise and fall of the sun?

{*} - missing a quantifier there?

Well, as I understand it, even some protozoa are sensitive to light, and at that point, we are talking about single-celled creatures (protozoa), so it shouldn't seem that strange that you can genetically trace all vision back to one ancestor. Tracking the sun? Perhaps. Or they may have simply used "vision" to regulate their depth, perhaps in the ocean. Interestingly enough, there are some bacteria are sensitive to magnetic fields, too.

Oh -- and the quantifier was supposed to be "forty." Sorry about omitting that...


This message is a reply to:
 Message 44 by RAZD, posted 11-28-2005 6:11 PM RAZD has acknowledged this reply

  
TimChase
Inactive Member


Message 50 of 219 (263880)
11-28-2005 6:36 PM
Reply to: Message 47 by RAZD
11-28-2005 6:21 PM


Re: Box Jellyfish
even if the organism has no brain? (netting to see with?)
(sounds like a strawman argument ...)

Well, all of this is purely academic unless the poor thing had gametes. No gametes, no reproduction, and no way of passing down its splendid genes no matter how well it might have been able to see.

But how could it have possibly had gametes if it were only single-celled?

Answer me that, Batman!


This message is a reply to:
 Message 47 by RAZD, posted 11-28-2005 6:21 PM RAZD has responded

Replies to this message:
 Message 51 by TimChase, posted 11-28-2005 7:46 PM TimChase has not yet responded
 Message 54 by RAZD, posted 11-28-2005 10:17 PM TimChase has responded

  
TimChase
Inactive Member


Message 51 of 219 (263917)
11-28-2005 7:46 PM
Reply to: Message 50 by TimChase
11-28-2005 6:36 PM


Re: Box Jellyfish
even if the organism has no brain? (netting to see with?)
(sounds like a strawman argument ...)

Well, all of this is purely academic unless the poor thing had gametes. No gametes, no reproduction, and no way of passing down its splendid genes no matter how well it might have been able to see.

But how could it have possibly had gametes if it were only single-celled?

Ok. Here is the serious answer. Before multi-celled organisms, a single-celled organism had to be a jack-of-all-trades, able to perform everything for itself, including sensation, reproduction, digestion, etc. However, being a jack-of-all-trades, it wasn't especially good at any specific job. To get good at performing specific jobs, you have to have specialization -- which requires multi-celled organisms.

Now for an example of a species which is at the very threshold of multicellularity, you might look at the social amoeba. Interestingly enough, they might be helpful in understanding the protein pathways in the human brain...

ScienceWeek
2. THE SOCIAL AMOEBA D. DISCOIDEUM
http://scienceweek.com/2003/sw030425-2.htm

Social Amoeba Sheds Light On Communication In Human Brain.
By Sherry Seethaler
http://ucsdnews.ucsd.edu/newsrel/science/svalium.asp

Genome of social amoeba shows its importance as research model
Category: Genetics News
Article Date: 05 May 2005
http://www.medicalnewstoday.com/medicalnews.php?newsid=23858


This message is a reply to:
 Message 50 by TimChase, posted 11-28-2005 6:36 PM TimChase has not yet responded

  
TimChase
Inactive Member


Message 53 of 219 (263951)
11-28-2005 9:44 PM
Reply to: Message 52 by gnojek
11-28-2005 8:10 PM


Re: Leave the silly analogies to the IDots
...

In the first post it was said that the bacterium would move several times its body length every second and the boat with the propeller would move about 3.

Ok, it sounds like the bacterium is winning when scale is not taken into account.

Then you say that because the meecetrap (I mean boat, sorry) would go much slower with a long hose instead of a propeller this means that a propeller on a bacerium would make it go faster.

But we are talking about something on the macroscale and something on the microscale, if not the molecular scale.

...

... on the scale of a flagellum ,would a propeller-like configuration actually impart MORE or LESS motility to the bacterium?

But from your post it makes it sound like scale-to-scale the bacterium beats the boat. (I'm guessing several is more than 3.)
....

I hope no one minds if I throw-in my two cents.

Personally, I think it is a mistake to make rough comparisons between the microscopic and the macroscopic levels: the physics is all different. You have seen waterbugs walking upon the surface of the water -- well generally that wouldn't work for you or me because the waterbug is quite literally supported by surface tension -- which works at that scale.

An ant can fall off the top of the Empire State Building and safely land on the ground. Why? For the same reason that the waterbug can walk on water: the volume to surface area ratio is proportional to the scale for objects of similar shape, and the volume is what is proportional to the mass or weight, whereas the surface area is what is responsible for support or air resistance. At the molecular level things become even more strange. There are "motors" which are driven by thermal fluctuations, for example, and now it appears that some proteins make use of quantum tunneling for their peculiar chemistry. For this reason, I will tend to look upon any rough comparison between levels as different as this with a certain amount of skepticism.


This message is a reply to:
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TimChase
Inactive Member


Message 55 of 219 (263960)
11-28-2005 10:21 PM
Reply to: Message 54 by RAZD
11-28-2005 10:17 PM


Re: Box Jellyfish
Heh -- I thought I got to be the joker!

Anyway, gotta go. Have to catch a bus -- stayed late getting a client build done. But I will be checking back!


This message is a reply to:
 Message 54 by RAZD, posted 11-28-2005 10:17 PM RAZD has acknowledged this reply

  
TimChase
Inactive Member


Message 57 of 219 (264070)
11-29-2005 9:44 AM
Reply to: Message 49 by jar
11-28-2005 6:36 PM


Re: Box Jellyfish
Earlier post:

I understand that the Box Jellyfish has a whole range of eyes, some simple, some complex. Does anyone know how that gets coded?

Most recent post:

Thanks for the article. Unfortunately it just raised even more questions as any good article should.

Well, at this point I am just guessing, but if what you are wondering is what specifically happened at the genetic level, I suspect that this is a case of gene duplication (or perhaps either segment(al) or chromosomal duplication) followed by what is called "sub-functionalization." (Same sort of thing happened in primates at a less dramatic level, taking us from dichromatic vision to trichromatic vision.)

Some of the genes responsible for both kinds of eyes are the same exact genes, some are different -- the latter due to specialization made possible by the duplication, then mutation. At some point in the development of the embryo, the different kinds of eyes are probably almost identical, but different protein-markers establish a contexts which lead to different genes being expressed in the development of the different kinds of eyes. (This would also be comparable to hind wing development in the common housefly, where the expression of a protein suppressed the full development of the second set of wings. For more on this, you might want to see "Endless Forms Most Beautiful," pg. 96-8, particularly the section entitled "Making Serial Repeated Modules Different.")

This message has been edited by TimChase, 11-29-2005 10:11 AM


This message is a reply to:
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