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Adaptation VS Evolution

Sat, 2009-04-11 05:32 — Celia
Question:: 
Just wondering if adaption is a reality in terms of evolution. Are the changes always a random mutation or do living creatures actually adapt to their environment? I recently saw a blip about cuttlefish on the nightly news ... very interesting the way they can willingly change their skin to match any background; even something outside of nature. This made me think about adaptation on in a general sense. Does that happen?
Atheist Answer: 

Living creatures can adapt radically to suit their environment during their lifetimes, but such adaptations are not reflected in their DNA and therefore are not passed on genetically. Only recombination (during sexual reproduction) and mutation cause genetic change.

The idea that deliberate adaptations become hereditary is the central idea of a rival theory to Darwin's, namely that of Lamarckian evolution. This theory actually is the way creationists tend to think of Darwinian evolution: unsupported by the evidence, discredited by contrary evidence, and almost entirely dismissed by the scientific community.

That said, Darwinian evolution does allow for some developments that might appear Lamarckian in nature. While deliberate adaptations are not passed on genetically, they can be passed on by instruction and example. If a new skill is deliberately taught to the young for many generations, it may actually affect the selection process; mutations which benefit that skill may be favoured. Therefore it's possible for adaptations to eventually be reflected genetically, but only in a roundabout way.

- SmartLX

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Mon, 2009-04-13 02:56 — Celia

Thanks, and ...

Thanks for the info. I have not clicked on your link yet though.

I am wondering how such a thing as being able to change the appearance (quite detailed too) to any background is something that would be a random mutation (as in the cuttlefish). I can see blending in with one thing could easily happen, but I don't understand how the ability to change to anything could.

Also, I saw a seahorse at an aquarium that looked like it had seaweed growing off, and that really struck me. When it slowly swam, it looked just like a piece of seaweed floating. At first glance one would literally think there was seaweed growing off it's back. I just don't see how that would just happen (especially when it happened to be so conveniently something that would protect it in the environment it happened to be in). It would be easier for me to believe that somehow our cells could sense their surroundings and adapt as needed.

Mon, 2009-04-13 07:20 — SmartLX

Baby steps

It helps to understand that features like those you mention don't have to come in fully formed.

Once seahorses started living near seaweed, they didn't have to look exactly like it. Those that had so much as a passing resemblance to it had a chance of being mistaken for seaweed by predators, who would then aim for some other sea creature. Those who looked even slightly more like seaweed than others had a better chance of not being eaten than those who looked slightly less like seaweed. Thus there was a selective pressure every generation, favouring at every stage those seahorses who looked more like seaweed, until it was almost impossible to resemble it any more closely.

Cuttlefish are in a different predicament: they appear against a variety of backgrounds. If they developed the ability to change their colour in the slightest (this is not actually that unusual; even we can do it by blushing) then there were more places where they would not be noticeable. Every little advancement in their photochromia was a help, and now they're almost perfect at it.

Mon, 2009-04-13 16:21 — Celia

SmartLX, I understand what

SmartLX, I understand what you're saying, but it's one of those things that just doesn't quite add up for me (like, if it sounds too good to be true ...). The whole ball of wax just seems to be a bit too miraculous (I'm not saying it isn't so, it just seems out there [no matter if you go with evolution, adaptation, creationism]), but I guess something has to be the truth, huh?

I will have to remember to always embarrass myself near something red so maybe people won't notice. Funny how we blush becuase of discomfort and then feel even more uncomforatble for blushing. : )

The cuttlefish is pretty extreme in it's change potential, creating stripes, pebbles, polka dots ... whatever, and even held it's legs out a certain way to mimic man-made stipes more effectively.

When thinking of things such as the seahorse with the seaweed looking appendages, it is difficult for me to think that a sort of look-a-like fluke would end up becoming perfection during extended breeding.

Is there any sense in which this process has shown in man as far as appearing it could be an adaptation type of thing (that would have actually started from a random mutation)? Losing hair and standing upright doesn't appear that way to me, but maybe I am not focused on the right things. I know we do have a more advanced brain but that doesn't seem like the same type of thing to me either.

In any event, thanks for humoring me. : )

Mon, 2009-04-13 17:55 — SmartLX

Climbing Mount Improbable

I know it can be hard to wrap your head around it when you're looking at the "finished" products of evolution. Without fully understanding the specific processes by which they came about, it's possible to imagine a partially-formed feature at any stage in its development and see two things: an advantage it provides in its current state, and a reason why a slightly better version of it would improve survival and procreation prospects.

Richard Dawkins wrote a whole book about this one aspect of evolution, which I recommend to you: Climbing Mount Improbable. He likened it to looking at an animal at the top of a sheer cliff and thinking, "How did it climb up there?" We don't see the gentle slope on the other side of the mountain until we go and look.

Tue, 2009-04-14 02:29 — Celia

Thx. So much reading but so

Thx. So much reading but so little time. I will add that to my list. : )