Metamorphoses and insect flight; How bugs got their wings.

[Christopher]

Why is it that a caterpillar has little resemblance to a butterfly ?

 

Darwinian evolutionary models have yet to explain how this abrupt transitional phases could develop in a liner way.

The following is probable non linear explanation of how the pupa stage of insect development could be compressed into and adaptive evolutionary stage toward flight.

 

One mechanism needed, is for the flightless

ancestors of the insects to develop a morphological feature that could accumulate information toward flight.

 

But that still can not explain the whole metamorphoses process.

 

How would this developmental leap of the pupa stage be compressed in this way?

 

I believe the key steps to build this new body plan lies in the molting stage.

In the pupa stage the wings appear to form from the outer skin. This then must be the morphological feature that collected the Information needed over generations to develop flight. Just as the bird developed the capability of flight though the tail feathers.

But how?

 

 

Here is a scenario; eggs hatch in the ground, the caterpillar climbs into the trees and feeds and grows. It goes though a molting stage during this stage it climbs to the high part of the tree and uses the still connected, but light weight skin to catch the wind and disperse though the air.

 

This cyclical adaptation will not only form wings but will simultaneously become compressed and combined into the molting stage.

 

 

 

But, prior to that [millions of years ago] the skin would be retained just long enough to catch the wind and disperse the caterpillar though the environment. As soon as the caterpillar landed it would finish molting and discard the "sail" of light skin and remain a caterpillar.

After millions of generations of this process it will transform the temporary sail into a permanent set of wings.

 

 

This cyclical adaptation will not only form wings but will simultaneously become compressed and combined into the molting stage .

 

 

The pupa is nothing more than a complex adaptive molt, That has developed over time by compressing information of past complex molting behavior.

 

Its quite simple.

 

 

The partially molted skin is the morphological feature needed to collect information to create wings, they became the wings.

[Boerseun]

The reason the bugs don't resemble the adult form is because it is actually two different animals.

 

When the larva first began to develop from the egg, its cells were segregated into two groups. Some stopped dividing after a few hours and remained generalised in form and in dense clusters. The rest continued to build the body of the caterpillar. After it hatched and had begun to feed, its body cells divided no more. Instead, they simply enlarged until, by the time the caterpillar was full grown, they were vastly distended and many thousand times bigger than their original size. All this time, the other cells remained tiny and inactive.

After the caterpillar has spun its cocoon, the giant cells die and the dormant cells suddenly begin to divide rapidly, nourishing themselves on the soup of the disintegrated caterpillar body. The insect, in effect, is eating itself. Slowly, it builds a new body of a completely different form.

 

But in effect, it's a brand-spanking new animal that eventually emerges from the cocoon, with no resemblance at all to the caterpillar that went in. So, it's doubtful they got their wings from the skin on the caterpillar's back, seeing as that skin was diluted as well in the metamorphoses process.

[Christopher]

The reason the bugs don't resemble the adult form is because it is actually two different animals.

 

When the larva first began to develop from the egg, its cells were segregated into two groups. Some stopped dividing after a few hours and remained generalised in form and in dense clusters. The rest continued to build the body of the caterpillar. After it hatched and had begun to feed, its body cells divided no more. Instead, they simply enlarged until, by the time the caterpillar was full grown, they were vastly distended and many thousand times bigger than their original size. All this time, the other cells remained tiny and inactive.

After the caterpillar has spun its cocoon, the giant cells die and the dormant cells suddenly begin to divide rapidly, nourishing themselves on the soup of the disintegrated caterpillar body. The insect, in effect, is eating itself. Slowly, it builds a new body of a completely different form.

 

But in effect, it's a brand-spanking new animal that eventually emerges from the cocoon, with no resemblance at all to the caterpillar that went in. So, it's doubtful they got their wings from the skin on the caterpillar's back, seeing as that skin was diluted as well in the metamorphoses process.

 

 

 

 

 

We are speaking of morphology from two separate view points, you are observing a genetically driven morphological transformation that is an end product of adaptive behavior.

The model I just presented is a possible adaptive scenario that is needed to produce new genetic info to build new morphological features.

Also a cyclical process that can compress this genetic information though successive generations. Remember DNA is not a forward seeing, only adaptive.

 

 

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From another forum and thread

Quote:

Metatron {Christopher} definitely nails one aspect of this issue: molting is a prerequisite for nearly all major organizational changes in insects. These are animals that periodically grow entirely new skin under the old one. Opens up all sorts of possibilities, while closing others.

[Entomology Grad Student Interests: Insect systematics]

[Southtown]

The partially molted skin is the morphological feature needed to collect information to create wings, they became the wings.

How was this new "information" recorded and transferred to succesive generations?

 

Remember DNA is not a forward seeing, only adaptive.

Are you saying DNA records the changes instead of instigating them by mutation?

[Christopher]

How was this new "information" recorded and transferred to succesive generations?

 

 

Are you saying DNA records the changes instead of instigating them by mutation?

 

 

Remember the arthropods needed to change their body plan from a ground or water dwelling creature to a creature of the air.

 

This transition is compressed into to the pupa stage.

 

But before this pupa stage could develop, an original simple molting stage acted as a basin of attraction for genetic mutations that selected for traits that enabled the organism to disperse out into the environment and breed with non hatch mates.

 

The more successful the individual hatchling was at catching the air and moving further from the hatch sight the more likely it was to successfully breed and feed, therefore the transition point between land and air became the molt. Over generations genetics split the arthropod into two distinct forms on ether side of the molt. These transitional traits would become compressed into this stage that separates not only feeding and flying, but more importantly between feeding and breeding. This is the reason insect flight is so tied to the mating of modern insects.

 

Just as the amphibians transforms themselves from a tad pole-pollywog-frog thus reenacting an evolutionary transition. the arthropod encapsulated their transitional phase into a genetic convergence point.

The advantage in this is that the passage from one form to another occurs all at once in a nonlinear way allowing the morphological structure to disassemble its cellular matrix and to reassemble into another.

This nonlinear assemblage point became a basin of attraction for random mutations, allowing the organism an opportunity to integrate new DNA sequences, creating new traits exponentially.

 

 

What the caterpillar calls the end of the world,

 

the rest of the world calls butterfly.

 

- Richard Bach

[Southtown]

Remember the arthropods needed to change their body plan from a ground or water dwelling creature to a creature of the air.

 

This transition is compressed into to the pupa stage.

 

But before this pupa stage could develop, an original simple molting stage acted as a basin of attraction for genetic mutations that selected for traits that enabled the organism to disperse out into the environment...

How does environmental necessity dictate the mutation of DNA?

 

... and breed with non hatch mates. The more successful the individual hatchling was at catching the air and moving further from the hatch sight the more likely it was to successfully breed and feed, therefore the transition point between land and air became the molt. Over generations genetics split the arthropod into two distinct forms on ether side of the molt. These transitional traits would become compressed into this stage that separates not only feeding and flying, but more importantly between feeding and breeding. This is the reason insect flight is so tied to the mating of modern insects.

And caterpillars aren't capable of reproducing, are they? Very few larva are capable of reproducing that I know of. Wiki

 

Just as the amphibians transforms themselves from a tad pole-pollywog-frog thus reenacting an evolutionary transition. the arthropod encapsulated their transitional phase into a genetic convergence point.

The advantage in this is that the passage from one form to another occurs all at once in a nonlinear way allowing the morphological structure to disassemble its cellular matrix and to reassemble into another.

This nonlinear assemblage point became a basin of attraction for random mutations, allowing the organism an opportunity to integrate new DNA sequences, creating new traits exponentially.

Breeding would blend traits into offspring forthright. How could cross-breeding cause an encapsulation of nonlinear changes?

 

How would encapsulation attract "new DNA sequences"? By increasing mutation probability?

 

The mechanism would still be mutation, correct? In which case, the mutation failure rate would also be increased exponentially, so the odds of the genetic inheritance of successful mutation would probably decrease, not considering the mutations that destroy any abilities to reproduce (or eat or breathe, etc.)

 

Moreover, the stability of any successfully-transferred, beneficial genetic traits would decrease as mutation rates increased, adding more opposition to successful evolution.

[Christopher]

How does environmental necessity dictate the mutation of DNA?.

 

Its called natural selection

 

 

.

And caterpillars aren't capable of reproducing, are they? Very few larva are capable of reproducing that I know of. Wiki.

 

I never said they did, however how do you think the non-flying ansestors of these insects reproduced ?

 

.Breeding would blend traits into offspring forthright. How could cross-breeding cause an encapsulation of nonlinear changes?.

 

 

The molt-pupa stage is the pudding, the success of the offspring to mate is the proof of the genitic changes that occur whithin the complex molt. This cycle will drive morphological change.

 

.How would encapsulation attract "new DNA sequences"? By increasing mutation probability?.

yep sounds good. this destabilization of the cellular matrix would increase that chance for mutation to manifest and run though the R@D side of the cycle.

 

.The mechanism would still be mutation, correct? In which case, the mutation failure rate would also be increased exponentially, so the odds of the genetic inheritance of successful mutation would probably decrease, not considering the mutations that destroy any abilities to reproduce (or eat or breathe, etc.)

 

.Moreover, the stability of any successfully-transferred, beneficial genetic traits would decrease as mutation rates increased, adding more opposition to successful evolution.

 

I do not completely agree with your equation, yes mutation failure would increase but that’s only because mutations in general will increase. The genetic ratio of what works better and what doesn’t remains the same.

[CraigD]

I believe the key steps to build this new body plan lies in the molting stage.

That’s an interesting and reasonable speculation. While I’m not a molecular biologist, what I’ve read of the field leads me to doubt it’s correct, though.

 

Most of the research of which I’m acquainted is focused on the family that includes fruit flies, Drosophilidae, in order Diptera. Intrestingly, while “diptera” literally means “2-winged”, all members of it actually have 4 wings, with the rear winds reduced to small stubs – “halteres” - that are useful in maintaining stability in flight, making them similar to 4-winged insects like dragonflies and butterflies.

 

Research has pretty extensively mapped the genes responsible for producing normal and “haterized” 2-winged insects. These genes - Ultrabithorax is one – are variations on the ones involved in leg formation, indicating that wing formation is related to leg formation. It appears that the important part of a wing, from an genetic perspective, is the stubby part containing the muscle, not the large, thin part that gives the insect the needed aerodynamics for flight.

 

In general, I think evolutionary biology has passed from a time when one could make logical speculation based on the shape of various insects at various stages of its evolution, into one where the identification of genes responsible for these shapes is the primary focus. ;) In a way, this is unfortunate, as few armatures currently have the equipment or knowledge to do this sort of research (though we are highly capable of reading about it ;) )

 

Fortunately, your idea can be verified in an old-fashioned way: just collect pupae at various stages of metamorphosis, dissect them, and see exactly how the wings form. Though its likely that many people have done exactly this in centuries past, there’s nothing wrong with repeating experiments, which can sometimes be easier than researching past results.

 

Either approach is sure to be more productive than engaging in the sophist-like debate that the internet in general, and sciencefurums in particular, is so adept at hosting. The ancient greeks (who, you may recall, were reluctant to dissect stuff, apparently for deeply held religious reasons) would love internet forums (though they’d certainly have 4220 ;) )

[Southtown]

Its called natural selection

Natural selection "filters" the mutations, it doesn't instigate them. Nor does environmental necessity ensure that those mutations will fit a need. The mechanism is randomness + time.

 

 

I never said they did, however how do you think the non-flying ansestors of these insects reproduced ?

I have no idea. But without evidence, it could be just as easily assumed that butterflies evolved through some other phylum and then suffered degenerative mutation, that was then naturally selected. The point is that we have to consider everything and not use conjecture so freely. An argument must rest on more than the theory it's attempting to support.

 

 

I do not completely agree with your equation, yes mutation failure would increase but that’s only because mutations in general will increase. The genetic ratio of what works better and what doesn’t remains the same.

Well, you're right there. Sorry.

[Christopher]

Natural selection "filters" the mutations, it doesn't instigate them. Nor does environmental necessity ensure that those mutations will fit a need. The mechanism is randomness + time.

 

I really don’t see how anything I said contradicts this statement. What I am saying is the post pupa stage will be the filter for any random mutations occurring during the pupa-molt stage.

The advent of this metamorphic stage gives random mutation a second shot, EMBRYOGENESIS being the first.

 

quoteI have no idea. But without evidence, it could be just as easily assumed that butterflies evolved through some other phylum and then suffered degenerative mutation, that was then naturally selected. The point is that we have to consider everything and not use conjecture so freely. An argument must rest on more than the theory it's attempting to support.quote

 

 

My senerio is just much more simple and straight forward.

[Christopher]

Quote Fortunately, your idea can be verified in an old-fashioned way: just collect pupae at various stages of metamorphosis, dissect them, and see exactly how the wings formed.Quote

 

 

 

This has been done, the wings or formed as a new more complex skin that unfurls into wings this is crux of this model. The skin or more correctly exoskeleton is the morphological feature that connected the air to chance mutation,

just as a birds feather does.

[emessay]

Imagine our biosphere is big 'aquarium' for all living things to dance and acrobat showing beauty of their existence as a species; bird and bat flying, fish swimming, rodent gliding, carnivora running, kangaroo jumping, bipedal running. It's real theatre of conscious universe.

 

There are four fundamental force for locomotion of the creatures

1. Thrust and drag for running and jumping

2. Lift and weight for flying or gliding

 

And we've five kingdom of living creatures as real actors on Earth: Monera[bacteria], Protista [amoeba], Fungi, Plantae, and Animalia. Virus is other creature, but all are dancers and acrobats. Especially Animalia are real beautiful acrobats.

 

I don't know how start to apply Newton’s Laws of Motion and Bernoulli’s Principal from a virus to be a dancer and finally to be an acrobat. Looks like climbing improbable if we try to analyze it..