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Author Topic:   Can ToE explain human Brain development?
frako
Member
Posts: 2702
From: slovenija
Joined: 09-04-2010


Message 46 of 47 (580981)
09-12-2010 6:54 PM
Reply to: Message 44 by barbara
09-12-2010 3:50 PM


Re: Too many topics
Also how does ToE explain why most species have their own unique sensory capabilities that no two different species share exactly alike?

well if evry species would adapt the same sonar vision at some point in history just for the fun of it that would be a problem for evolution, how can chance produce so many same resaults. evan the eyes and hearing are diferent because natural selection needed them to be diferent or they wherent needed at all.

bats needed a form of sight that allows vision in pure darkness so they evolved sonar evan some blind peapole can use a primative version of sonar they produce sound than listen for the echo this shows how the adaptation for sonar vision could have started

a deer needed to have their eyes at the side of the head so they could see predators better it gives them a wider range of vision almost a full 180 degrees

wolves needed their eyes at the front so they can have 3d vision so they can better asses the distance and position of their pray

there are some fish that have 8 eyes

whales produce low herz sounds because they travle farther and they need to the ocean is big and its hard to find a mate in such a big place

this is all because of evolution its evolution that made this so.

Edited by frako, : No reason given.


This message is a reply to:
 Message 44 by barbara, posted 09-12-2010 3:50 PM barbara has not yet responded

Replies to this message:
 Message 47 by Nij, posted 09-13-2010 12:38 AM frako has not yet responded

    
Nij
Member (Idle past 2386 days)
Posts: 239
From: New Zealand
Joined: 08-20-2010


Message 47 of 47 (581022)
09-13-2010 12:38 AM
Reply to: Message 46 by frako
09-12-2010 6:54 PM


Re: Too many topics
Your explanation of these points is a little skewed, in that the trait was not needed and thus appeared as it is. It just happened to make the critter survive more often and got selected for:

bats needed a form of sight that allows vision in pure darkness so they evolved sonar evan some blind peapole can use a primative version of sonar they produce sound than listen for the echo this shows how the adaptation for sonar vision could have started

Bats didn't "need" echolocation. It simply happened that in the dark environment, the ancestors that could hear better were more able to tell where objects were. Over time, they end up developing extremely good hearing. At roughly the same time, one of them figures out that going "ping!" makes it easier to find objects because you know how the ping will sound, instead of relying on the background noises and trying to determine which to focus on.

Maybe a couple of mutations also allow the ancestors an extended hearing range. Then maybe a couple more let them extend that ping to a higher frequency too -- this would also be selected for, as a higher frequency has a lower wavelength, and the best accuracy occurs when your wavelength is smaller. Bats hunt insects, so having a wavelength as small as the insects is a better thing to have. More food means living longer, means more kids, means that trait becomes more common.

So, you end up with creatures who emit high frequency sound and who are able to hear that sound well, and who can interpret the sound as relative locations of objects. Not because they "needed" it, but because that is how their ancestors developed under the selection pressures involved.

a deer needed to have their eyes at the side of the head so they could see predators better it gives them a wider range of vision almost a full 180 degrees

Similarly, deer did not "need" eyes like this. It simply happened that some ancestors had eyes located further around the head. This gave them an advantage because they could see the predator in more places, and were thus more likely to notice it and run away in time, and thus more likely to grow old enough to have children who receive this trait too.

Then the next generations have increasingly higher amounts of this type of eye location, while the ones who don't have it get eaten more and more often, and reproducing less and less often, untill you end up with few or none left.

Once again, this is not a sudden "oh shit! predators! we need eyes like this now!" effect. It is the accumulation of generations upon generations, thousands of them, of the effects of natural selection in action.

wolves needed their eyes at the front so they can have 3d vision so they can better asses the distance and position of their pray

Binocular vision -- using two eyes to triangulate objects' distance and relative location -- evolved similarly: those ancestors that had eyes nearer the front were more able to use them when determining the distance to prey. Those ancestors could hunt better, and eat more often, and have more offspring to pass it onto. Conversely, those who didn't have this neat trick hunted less well, ate less and had fewer offspring.

And that adds up to more of the first kind, less of the second, until one is entirely removed from the population because it simple cannot compete at all and is killed off before reproducing (you might get a few popping up because of recessive alleles or mutations, but again, they die and don't pass it on).



You made a common creationist -- and yes, I know you're not one -- mistake in interpreting what natural selection means.

These traits don't arise because the organism needs them. They arise because of whatever random effect is induced by their genetics, and they gain the advantage by it, so they pass it on more often. It's not something that happens overnight in one giant leap. It's something that happens over generations (centuries or millenia, often) in hundreds of small steps.



Now, on-topic, and answering the question:
These animals faced different selection pressures, and got different random genetic alterations. It's as simple as the reason you get two pair while your buddy gets a full house in poker: because they're the cards you got dealt. If you can win hands more often, you get to play more often, until you're playing (and winning) all the time. If you lose more often, you play less often, until you're not playing at all (and are losing all the time).

Edited by Nij, : Adding explanation.


This message is a reply to:
 Message 46 by frako, posted 09-12-2010 6:54 PM frako has not yet responded

  
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