Dragonfly design tips (bioengineers: flight mechanism "analogous to coaxial contra-rotating rotors")

CMI ^ | October 20, 2009 | David Catchpoole, Ph.D.

[GodGunsGuts]

Just how can the dragonfly perform its energetically-demanding aerial acrobatics—flying backwards or forwards, fast, slow or hovering—and remain airborne for such extended periods?

The answer, in part, is that it...

[UCANSEE2]

250 Million Years?

Yeah, but here's the thing.

250 million years is a span that I can't really understand fully. No one, not one single human, has ever experienced more than say, 100 years (unless we count the Bible reports of higher ages, which are possible). But let's go with 100 for sake of argument.

So, how does our conscious grasp the experience of that kind of 'lapse' of time? I don't think we can really.

[ElectricStrawberry]

I studied entomology with a grad student that photo-categorized 300+ sub-species of dragonfly just by their body stripes.

Unfortunately, most of MY bug-work involved deer ticks and skeeters.....disease carriers in the northeast.

Bugs are fun.

[UCANSEE2]

All exoskeletal creatures molt to grow.

Sure.

I didn't wrap up in a blanket, and turn into a crocodile.

[UCANSEE2]

Evidence for what?

Evidence for whom.

[Ira_Louvin]

What does this evidence show?

[FormerRep]

“I didn’t wrap up in a blanket, and turn into a crocodile.”

Can you prove that? It’s an absurd question to illustrate further the absurdity of your response. A caterpillar doesn’t turn into a different animal when it becomes the butterfly - it only matures to it’s adult body form through molt. Not if you’re object is to appear to be an ignoramus for the fun of it then you’ve succeeded.

[GingisK]

[ElectricStrawberry]

Ummmm....ever actually studied lepidopterans past the "caterpillar + cocoon = butterfly/moth" kindergarten level stuff? I had the priveledge of dissecting Manduca sexta cocoons at different metamorphosis levels....fascinating to actually learn stuff.

....and I wouldn't make the blanket claim that caterpillars are fuzzy...some are...some are not.

[FormerRep]

I just read your tag line and laughed out loud.

[UCANSEE2]

Ummmm....ever actually studied lepidopterans past the "caterpillar + cocoon = butterfly/moth" kindergarten level stuff?

Nope.

....and I wouldn't make the blanket claim that caterpillars are fuzzy...some are...some are not.

Some are green, some are blue.

[UCANSEE2]

What does this evidence show?

It doesn't 'show' anything. It merely exists.

[Ira_Louvin]

OK then since you want to play games, How does this evidence support the authors assertion?

[UCANSEE2]

Can you prove that?

Here's a picture of me heading off to work.

A caterpillar doesn’t turn into a different animal when it becomes the butterfly

Then what is the definition of metamorphosis?

[UCANSEE2]

How does this evidence support the authors assertion?

You must first define the author's assertion, as you read it, before I can answer whether the evidence even applies.

[FormerRep]

"Then what is the definition of metamorphosis?" Precisely what I described above. Metamorphosis –noun, plural -ses  /-ˌsiz/ Show Spelled Pronunciation [-seez] Show IPA . 1. Biology. a profound change in form from one stage to the next in the life history of an organism, as from the caterpillar to the pupa and from the pupa to the adult butterfly.

[UCANSEE2]

a profound change in form

Sounds just like what I said.

I think I said it changes to a different creature, and I understand why you object to that.

I should have said, it changes to a different form, or a totally different 'appearing' creature.

[Ira_Louvin]

I guess reading comprehension is not one of your strengths.

Here is my first post again.

“Surely it makes much more sense to say that four-winged dragonflies and two-winged flies were each designed to do what they do do, and what they do do, they do do well!”

What empirical evidence does the author cite to support this assertion?

[whattajoke]

Maybe the author is citing the fact that they have survived for like 250 million years, unchanged. I'd say that was pretty good evidence.

The author does not believe that the earth is older than 10,000 years. I know this because GGG posted the article, and GGG supports a young earth fantasy. I can't imagine that GGG would post a creationist article that disagrees with him on this incredibly important point.

Now, if you're saying that a creature who remains "the same" for such a long period of time somehow contradicts evolutionary theory, you are quite simply incorrect.

First, dragonflies have changed rather dramatically in that time (mostly morphologically) and secondly, even if they hadn't (which they most certainly have), it would still fit into evolutionary theory.

IOW, I don't understand your point - or the point you are trying to convey on the article.

[FormerRep]

Still the same animal but looks different... I can agree with that.

[RFEngineer]

God’s evolution at work!