by zound 25 Replies latest jw friends
The control gene that triggers the production of an eye is called "eyeless" - geneticists are weird like that.
Eyeless has been transplanted from mice to fruit flies for example causing them to sprout new eyes on their legs or antenna.
Interstingly they don't grow mice eyes. The gene simply instructs other genes to do their job of making an eye.
Shadow asked- So how was it again that your photoreceptors hooked up with the brain and optic nerve?
The optic nerve itself is an extension OF the brain, and the retinal cells inside the eye represent an outgrowth OF the brain; that's precisely why the optic nerve is called a "nerve" (cranial nerve II). In fact, interesting factoid is the optic nerve is the only part of the brain than is directly observable with relatively-simple hand-held instrumentation (a device called an ophthalmoscope) vs having to imagine the brain via an MRI/CT scan.
Direct observation of the optic nerve is often important when diagnosing brain conditions such as mass-occupying tumors or brain infections, where the optic nerves can easily be seen to be bulging outwards (in most patients, they're normally like belly buttons, i.e. 'innies') since the intracranial pressure rises inside the skull but the nerve tissue is forced to bulge into the vitreous cavity of the eyeball. The condition is known as 'papilledema', and presents with a very distinct appearance, depending on whatever underlying condition is causing it (the list of known causes is long, and requires a lengthy work-up via the process of elimination to find the actual cause and treatment).
Shadow asked- The only thing crazier than believing in a creator is not believing in one
You're clearly a believer, so I'm sure you're willing to put your $$$ and life where your faith is, and next time you have a problem with brain seizures from some unknown cause, you'll simply pray to Jehovah, then?
JWs die for their denial and ignorance, as is their right. The ironic thing is, JWs are just as subject to the rules of natural selection as anyone else, whether they understand or accept those beliefs or not. It's not like a belief in Gods, where NOT believing in a fantasy God is harmless; believing in a God is downright deadly at times.
Adam
Marked
A most excellent thread!
To people pondering how different anatomy evolved at the same time, the anatomy has to increase in function and be refined over time. The optic tract existed before the photorecptors for example. Before you go 'but wait!'....it wasnt an optic tract originally, it would have had a different role or even been a simple neuron. It isnt that there was magically a photoreceptor on the top of a fishes face and nothing connected to it, then magically over time an optic nerve developed and connected to it, whilst at the same time or further down the line the brain developed the occipital visual region for processing the data. That is back to front, think function and anatomy over evolution. Evolution is not the process of something from nothing, but something else from something! So the photorecptor and optic nerve was something else that was functional in that organism first for example.
In fact thinking functionally, helps to breakdown what evolved first and then we can explore why. Wings on some birds began as little limbs that helped the earlier species negotiate brush and jungle enviroments! Ears were initially bones in the jaw, later mutations allowed these vibrating bones to become functional in detecting what we call sound. Refined over millions of years we have reasonably good anatomy for hearing.
Religious members often note the flagellum of sperm, a rotary propulsion system as irreducibly complex, i.e. that its parts have no function if broken down into smaller units. Though this is an example of how to think about evolution, it is also an example of how ignorance can trap people too. Simply repeating what you hear and not doing some simple research may hold you back for years, reassured in false information. The coding for turbines is in all simple cellular life, turbines exist in the mitochondria of all cells. Just as our powerplants use turbines to transfer energy from non usable to usable forms, so does the cell (ATPase). This turbine is only a few steps away from a flagellum. There are plenty of papers on the devlopment of those steps.
And below, the atpase as found in huge numbers in all living cells....
When I first took on evolution properly, I thought I had some good ammo in discussing the eye and the flagella. It didn't take long to realise how misinformed I was :( ....... Thankfully :) x
snare
@cofty
That's hilarious that the Watchtower quoted Jerry Bergman since he an ex-JW.
I thought there were two Jerry Bergmans - one a YEC and one an ex-JW who had written about JW mental health issues. It would appear they are the same person.
The interesting thing there is that some parts of the ex-JW community respect his works on mental health yet they are subject to the same criticisms as his work on biology.
Just shows the importance of research on the research!
Marked
