“In fact, if the Meganeura, or giant dragonflies, of prehistory were still around...”
You would need a certain radioactive lizard to clean up the infestation.
Posted on 08/24/2016 5:01:41 PM PDT by Extremely Extreme Extremist
Um, since they mostly eat mosquitos and flies, I’m all for their ability to do so!!!
Um, since they mostly eat mosquitos and flies, I’m all for their ability to do so!!!
Dragon Flys Matter
“In fact, if the Meganeura, or giant dragonflies, of prehistory were still around...”
You would need a certain radioactive lizard to clean up the infestation.
Jimi Hendrix would disagree, as dragonflies are the best way to get to his Spanish Castle...
And that’s how you know FR is cool. Yes. Giant Dragonflies are indeed a menace that may only be neutralized by Godzilla. We have a movie to prove it.
Freegards
But they are prey to the Robber fly. I've seen Robber Flies catch a couple of dragonflies.
Robber Fly, about half the size of most average Dragonflies, a little over an inch long.
I've never been bitten by a dragonfly, but have had several perch on a finger for a couple of minutes. Butterflies too.
I've taken loads of pictures of them...
Not easy to photograph flying, but I've been able to get a few shots.
What is going on with Flickr? It's been incredibly sluggish the past couple of weeks...so slow it's annoying to use these days...
Yes. Very interesting article. Thank you. Dragon flies are amazing showing the glory of God.
Fire?
PFL
The O2 level wasn’t that much higher.... and there is too much humidity and non-flammable elements in the atmosphere for it to ignite anyway.
“Oxygen and Paleofires.
The level of atmospheric oxygen cannot rise indefinitely unless the frequency of forest fires becomes so excessive that plant life cannot persist. This has been pointed out by Watson et al. (27), who emphasize that fires serve as strong negative feedback against excessive O2 variation. Conversely, O2 cannot have dropped to such low values over Phanerozoic time that fires became impossible. Fossil charcoal, as evidence of paleofires, has been found for all times that trees have populated the land, and the lower limit for the production of charcoal has been estimated to be at about 13% O2 (28). By contrast, the upper limit for O2 is in dispute. On the basis of experiments on the ignition of paper strips at different oxygen levels and fuel moisture contents, Watson et al. (27) concluded that past levels of atmospheric O2 could never have risen above 25%. However, consideration of actual forest fires and the response of ecological disturbance to fires led Robinson (29) to conclude that greater O2 variation might occur and that, at any rate, paper is not a good surrogate for the biosphere. In fact, Robinson states paleobotanical evidence for a higher frequency of fire-resistant plants during the Permo-Carboniferous, supporting the idea of distinctly higher O2 levels at that time. “
http://www.pnas.org/content/96/20/10955.full
Atmospheric oxygen over Phanerozoic time
“On the basis of experiments on the ignition of paper strips at different oxygen levels and fuel moisture contents, Watson et al. (27) concluded that past levels of atmospheric O2 could never have risen above 25%. However, consideration of actual forest fires and the response of ecological disturbance to fires led Robinson (29) to conclude that greater O2 variation might occur and that, at any rate, paper is not a good surrogate for the biosphere.”
Yeah, I would say he was wise to revise his upper limit:
“Analyses of the gases in these bubbles show that the Earth’s atmosphere, 67 million years ago, contained nearly 35 percent oxygen compared to present levels of 21 percent.”
http://geology.com/usgs/amber/
That’s pretty wild. They can either hear you and/or feel the air pressure.
If one ever talks back ....... RUN!!!!
Among the large cats, cheetah is the only pure pursuit predator.
The rest make do with a combination of ambush and short-duration pursuit, or plain ambush.
I’ve seen a domestic cat (plain barnyard variety shorthair) leap straight up six feet and snatch a dragonfly out of the air.
The cat did not wind up for the move - minimal crouch, briefest lineup. The dragonfly wasn’t obviously engaged in a search or chase - just flying straight and level, here to there.
The author didn’t do badly, in insectological research. But he out of his depth on the tracking and interception of aerial targets.
The problem is indeed more complex than striking a target on the ground, from another point on the ground, but humans have been doing it for over a century - at first, with only the slimmest knowledge of flying and the most rudimentary aiming aids. Human intervention was taken out of the loop and the job was handed over to electronic brains in the 1950s ... though “brains” is too powerful a description for the simple sensors and homing circuits put into missiles at that time.
Onboard processing power has improved since then, but the rules for doing the job haven’t changed much. They haven’t had to.
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