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Author Topic: How did mimicry evolve?  (Read 9323 times)

Offline Asyncritus

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How did mimicry evolve?
« on: 31/12/2008 13:11:30 »
In my undergraduate days, I learned about this business of mimicry: and even then I was gobsmacked. There were so many amazing examples! One day, I saw on the drive, what looked like a heap of bougainvillea petals. (now I know they aren't really petals, so don't start yelling about that. This is for the non-technical persons reading this subject).

It wasn't a heap of petals, it was a group of insects looking so much like petals it was imposssible to tell them apart.

Then I found out about the stick insects which look so much like twigs, its untrue:



All that was bad enough, but then I started seeing the butterflies, and the two kinds of mimicry that exist: Batesian mimicry, and Mullerian mimicry.

Batesian mimicry describes the situation where an edible, tasty specimen, mimics a model which is unpleasant.

This one is unpalatable.


This one is.

Now I asked myself, how did that happen? The resemblance is so close, it's obvious that the similarity is designed. But these are unrelated species! So how did that happen?

Then there's Mullerian mimicry where the mimic is unpalatable, and so is the model.

Unpalatable:


Mimic, also unpalatable:



These are distinct, unrelated, recognisably different species.

So how come they look so much like one another, with the purpose of fending off predators?

Did they think: hey look, that one tastes bad, let's copy it?

Or what?
http://www.biodiversityexplorer.org/beetles/beetle_larvae_mimic.htm
« Last Edit: 31/12/2008 17:05:10 by BenV »


 

Offline MonikaS

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How did mimicry evolve?
« Reply #1 on: 31/12/2008 18:05:39 »
<FOG>What stick insects are "doing" is called mimesis BTW, it's not mimicry, people without a biology background often confuse those too. Crypsis has been suggested as the broader name for mimesis, mimicry and camouflage.</FOG>

As for mimicry: mutation and natural selection are a fine explantion for it.
 

Offline Asyncritus

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How did mimicry evolve?
« Reply #2 on: 01/01/2009 15:00:37 »
<FOG>What stick insects are "doing" is called mimesis BTW, it's not mimicry, people without a biology background often confuse those too. Crypsis has been suggested as the broader name for mimesis, mimicry and camouflage.</FOG>

As for mimicry: mutation and natural selection are a fine explantion for it.

Putting a name on something doesn't account for its existence, Monika.

If you invoke natural selection, then either half of the equation should be extinct. They're not.

.
 

Offline BenV

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How did mimicry evolve?
« Reply #3 on: 01/01/2009 17:16:05 »
Quote
If you invoke natural selection, then either half of the equation should be extinct.

Come on Asyncritus, you're slipping!  You know that statement is nonsense, as a sub population can be subject to natural selection in such a way that results in both the mutated population and the original population thriving.  You acknowledge this mechanism as fact, so why argue with it now?
 

lyner

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How did mimicry evolve?
« Reply #4 on: 02/01/2009 18:02:02 »
Using the correct words is clearly a bit of an effort for some people so here is the noddy version:
Some stinging insects developed vestigial stripes. Some didn't but would survive worse because they may die before getting to sting a predator. Because some of the stinging ones had stripes, predators which avoided the the most stripy ones survived better ('selecting' themselves, naturally, you could call it). Mutually, the stripy bugs and the smarter predators enhanced the stripy characteristic. Other, non-stingy insects also survived better and developed stripes, also. Nobody needed to 'copy anyone'- "hey, if I got a stripy jumper, too, the big boy may not pick on me" is not an evolutionary argument.
Apart from the objection to timescales involved, can there be anything wrong with that as an explanation for bees and hoverflies?

But when and where does God get involved in the process? Is it happening all the time or was it a one-off? Give me your answer, do. You argument stands of falls on the need for a clear reply with no holes in.

There is no need to insult me or call me stupid - just give a cogent answer.
 

Offline Asyncritus

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How did mimicry evolve?
« Reply #5 on: 03/01/2009 12:51:29 »
Using the correct words is clearly a bit of an effort for some people so here is the noddy version:
Some stinging insects developed vestigial stripes. Some didn't but would survive worse because they may die before getting to sting a predator. Because some of the stinging ones had stripes, predators which avoided the the most stripy ones survived better ('selecting' themselves, naturally, you could call it). Mutually, the stripy bugs and the smarter predators enhanced the stripy characteristic. Other, non-stingy insects also survived better and developed stripes, also. Nobody needed to 'copy anyone'- "hey, if I got a stripy jumper, too, the big boy may not pick on me" is not an evolutionary argument.
Apart from the objection to timescales involved, can there be anything wrong with that as an explanation for bees and hoverflies?

But when and where does God get involved in the process? Is it happening all the time or was it a one-off? Give me your answer, do. You argument stands of falls on the need for a clear reply with no holes in.

There is no need to insult me or call me stupid - just give a cogent answer.

Sophie

You're not thinking clearly, surely. I don't insult people and call them stupid unless provoked, and I certainly don't think you are either of those. Just misinformed, or misguided.

Fact:

Mimicry exists, and it is a well-recognised biological phenomenon - it is even named and properly described, as we all know.

Inferences:

There is an organism X which tastes foul.

There is an organism Y which doesn't.

Y mimics X - in other words, looks very very much like X as those photos show very clearly.

There is a 'why' involved here. If Rory Bremner mimics George Bush, then

a George Bush exists

b Bremner is actively, intelligently and designedly selecting characteristic A which will remind us irresistibly and forcibly of Bush.

Now let's transfer that to species X and Y.

Y mimics X, to compel predators to recall that there is a foul taste involved here. There ISN'T, in reality, but the predator is fooled into thinking so, and Y survives. But the deceit demands information, which an insect could never have.

If we went to see Bremner, we would never, conceivably, say natural selection is involved here.It certainly did not happen by chance that he looks like Bush.

Why then should we preclude intelligent selection and intelligent design being in action in the insect here?

The insect wasn't bright enough to figure out that stripe A and blotch B would make it look like X. It didn't have the necessary information. And even if it did, how could it get that into its genes?

There is no avoiding the fact that PURPOSE is very clearly displayed here. That PURPOSE is to ensure the survival of Y. Intelligently designed Technique, and intelligent design, are also very clearly displayed too: the technique of getting those patterns into into the genome. Design, which actually COPIES the original design pattern FOR A PURPOSE.

Random, natural selection is excluded - because there is very clear purpose obvious to anybody who cares to look and think.

I'll go on to camouflage briefly next.
 

blakestyger

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How did mimicry evolve?
« Reply #6 on: 03/01/2009 13:14:52 »
You're not thinking clearly, surely. I don't insult people and call them stupid unless provoked, and I certainly don't think you are either of those. Just misinformed, or misguided.

You don't do irony, do you?
 

lyner

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How did mimicry evolve?
« Reply #7 on: 03/01/2009 13:40:51 »
Asyncritus
So, when two hands of cards come out the same in two consecutive games, that means that either someone has made it happen or one hand 'knew' about the other hand and copied it?
Can you at least acknowledge that probability is at work in this example?
What is the essential difference between that scenario and the arrival of a similar characteristic through two different paths?

(And I should be grateful for an answer to my repeated question on the other thread, too.)
 

Offline BenV

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How did mimicry evolve?
« Reply #8 on: 03/01/2009 13:46:26 »
Asyncritus - do you think of your designer as one deity who is a bit daft, or a committee of sub deities?

Mimicry in itself denies intelligent design - the designer would not have built predators incapable of telling the difference between the mimic and the mimiced - what would be the point?
 

Offline Asyncritus

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How did mimicry evolve?
« Reply #9 on: 03/01/2009 21:06:25 »
Now ask yourselves, people, if this:



didn't happen by chance, then what about these?



stingray:



shrimp:



Frog:






frog



octopus:



scorpionfish:



mantis:



cicada:



scorpionfish again: can you see it?



Moth:




 

lyner

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How did mimicry evolve?
« Reply #10 on: 03/01/2009 21:29:20 »
Has anyone denied that these things exist?
Why not answer my question?
 

Offline BenV

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How did mimicry evolve?
« Reply #11 on: 03/01/2009 21:30:13 »
So we copied nature - good for us.  This is a common problem that you seem to be stuck on - just because we design something that works (cars, camouflage etc) doesn't mean it must have been designed in nature - that's an illogical leap.

It seems very strange that you are now trying to pick on an example of properties that are genetically controlled (skin colour & pattern, for example), and which would give a clear selective advantage - if anything, you would expect mimicry to evolve repeatedly, as it's advantageous.

Again, why would a creator confuse it's created predators so?

 

Offline atrox

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How did mimicry evolve?
« Reply #12 on: 23/01/2009 12:36:26 »
Nice pictures!
Nice examples for what Evolution can do.
 

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How did mimicry evolve?
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