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Author Topic:   Mimicry and neodarwinism
EZscience
Member (Idle past 5270 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 17 of 188 (345482)
08-31-2006 3:49 PM
Reply to: Message 13 by MartinV
08-31-2006 12:30 PM


FYI
Your selected examples of Batesian mimicry are mostly cases of highly specific mimics - those that resemble precisely certain other species that have aposematic protection. These are examples of very close ecological relationships, mostly from the tropics.
Were you aware that many other sorts of mimicry have evolved that are far less specific, but equally effective in enhancing survival under natural selection?
For example, many fly species in the family Syrphidae mimic wasps and bees - but they do so in a most general way. They do not mimic a specific wasp or bee, they just generally look like a wasp and that is enough to afford them protection, because most visually searching predators use a generalized image of certain things they want to avoid.
I know it seems unlikely on the surface that appearances of different organisms can converge to being so similar by mechanisms of mutation and random selection alone, but that is really the only explanation for it. The explanation, once properly understood, is quite adequate and no one has come up with anything more convincing.

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EZscience
Member (Idle past 5270 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 18 of 188 (345485)
08-31-2006 3:57 PM
Reply to: Message 16 by MartinV
08-31-2006 2:34 PM


There are plenty of examples where initially similar species evolve to look different.
It is a special case when taxonomically different species evolve to resemble one another.
In almost all the cases I know of, a clear advantage under natural selection can be demonstrated for at least one of the two species.
I submit there may have been cases where the proposed advantage was subsequently shown to be false, or where it has not yet been adequately identified, but that does not mean that no advantage for mimicry under natural selection exists in these cases.
You seem to want to infer some sort of underlying teleology that is unwarranted.
Edited by EZscience, : No reason given.

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 Message 16 by MartinV, posted 08-31-2006 2:34 PM MartinV has replied

Replies to this message:
 Message 20 by MartinV, posted 09-01-2006 3:26 AM EZscience has replied

EZscience
Member (Idle past 5270 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 22 of 188 (345673)
09-01-2006 8:54 AM
Reply to: Message 20 by MartinV
09-01-2006 3:26 AM


MV writes:
But the same do darwinists.
I am not sure if you understand what teleology is, but evolutionary biology has no part of it. Teleology refers to the implication that events happen for specific reasons and toward some sort of end goal. This seems to be what you are implying, but it is not consistent with a scientific explanation of anything biological.
MV writes:
They underlay to the phenomenons of mimicry their unwaranted myth of random mutation and natural selection as the only possible explanation.
We would not argue it is the only 'possible' explanation, only that it is the only adequate explanation based on the evidence. There is good evidence that both random mutations AND natural selection occur, and that living things are shaped by these processes. There is no evidence for teleology in all of biological science.
MV writes:
Panaxia quadripunctaria for instance has patterns that it can completely "disappeared" amongst leaves of prickly plants.
This is simple evolution of camouflage. Happens all the time. Every group of insect offspring are a little different from each other purely by chance. The more an insect happens to blend in with the background of its prefered habitat, the less often it happens to be eaten by visually-searching predators, hence such adaptive patterns are gradually adopted and improved on over many generations. I don't see what is so difficult to accept.
MV writes:
And how is it possible that insects with totaly different body plans as plants, that they can "mimics" plants with different logic of development?
Easy. You can paint the same portrait using watercolors, oil paints, or acrylic and still achieve much the same depiction of someone. There are multiple different developmental paths that can, under selection, evolve to produce things that are superficially similar in appearance, even though they are completely un-related and made up of different structures entirely.
Edited by EZscience, : No reason given.

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 Message 20 by MartinV, posted 09-01-2006 3:26 AM MartinV has replied

Replies to this message:
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EZscience
Member (Idle past 5270 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 37 of 188 (347001)
09-06-2006 3:03 PM
Reply to: Message 35 by MartinV
09-06-2006 2:38 PM


You seem disatisified with the traditional explanations for evolution of mimicry, but you haven't posited any alternative mechanism for their evolution. Succinctly, what is the alternative explanation we should accept if we are to abandon a Darwinian interpretation?
You are seemingly discounting any possibility of coincidence in the initial stages of mimicry evolution. Butterfly color patterns have a lot of latitude for variation without directly impacting fitness. Perhaps the largest evolutionary constraint on dramatic color pattern shifts is that wing pattern is a feature important in sexual recognition and sexual selection. Otherwise, or in cases where this constraint is weak, butterflies can 'experiment' with a broad range of color patterns... UNTIL some selective force picks up on one that confers an advantage for whatever reason.
To illustrate my point consider this link.
Coincidences happen all the time, including coincidental resemblences.
However, only those coincidences that result in some sort of advantage are going to become a genetic fixture in a population.

This message is a reply to:
 Message 35 by MartinV, posted 09-06-2006 2:38 PM MartinV has replied

Replies to this message:
 Message 39 by MartinV, posted 09-06-2006 3:35 PM EZscience has replied

EZscience
Member (Idle past 5270 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 40 of 188 (347021)
09-06-2006 4:03 PM
Reply to: Message 39 by MartinV
09-06-2006 3:35 PM


Well that's a good point.
Sexual selection adds another twist - IF it's based on physical appearance. However, as you point out, pheromones can be an important factor in mate recognition, although they are much more important in moths than butterflies. A lot of butterflies use visual signals in mate recognition, although visual behavioral displays may also be important. It is the moths, being largely nocturnal, that rely more heavily on pheromones for mate-finding.
So we need to balance potential benefits with potential costs.
Mimicry appearances could not evolve if they interfered strongly with mate recognition, or without some mechanism available to prevent wasted mating efforts directed at the model species.

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 Message 39 by MartinV, posted 09-06-2006 3:35 PM MartinV has not replied

EZscience
Member (Idle past 5270 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 41 of 188 (347024)
09-06-2006 4:08 PM
Reply to: Message 38 by MartinV
09-06-2006 3:23 PM


Re: choice and imagination.
MartinV writes:
Evolution - especially darwinism is not science. Do not deceit yourself, darwinism is as much science as was once marxism.
I am wondering how you derived this dogmatic assertion.
The scientific community (i.e. scientists from nany disciplines) are virtually unanimous in the view that evolutionary biology explains how life has changed, and continues to change.
And Marxism, as I recall, never claimed to be science.

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