Is the usage of air currents for flight as eagles do a more modern or ancient flight tactic? I'm mostly talking about the behavior of circling/gliding on rising warm air currents (or using them to keep stationary), and using downwards cold air currents to lower in altitude
Soaring flight is such an efficient and energy-saving behavior that it’s likely been around for as long as there have been flying animals with large enough wingspans to take advantage of it. We see examples of it being convergently evolved in every known group of powered-flying animals – pterosaurs, birds, bats, and there’s even a few insects that can do it such as butterflies.
Found only on birds, feathers are some of the most complex integumentary (skin) structures found in vertebrates.
There are two primary types of feathers: flight and down. Some birds, such as peacocks and birds-of-paradise, also have display feathers.
Flight feathers come in two categories of their own: remiges (wing feathers), and rectrices (tail feathers). These strong feathers are what allow most birds to fly. They have strong midline ridges, called the shaft (or rachus). The rachus is mostly covered in the fluffy-but-structured extensions, what most people think of as the “feather”, called the vane. At the bottom of the rachus, below the vane, is the bare quill (or calamus). Each extension on the vane is covered in many hooks and hooklets (also called barbs and barbicels), which is what birds are putting back into place when they preen - gotta keep everything in order to fly well!
Down feathers don’t have the hooks or the rachus of the flight feathers. There are many types of down feathers, but all of them serve the same basic purpose, which is temperature regulation. They trap air close to the bird’s body, which insulates it from the cold. When a bird puffs up in the middle of winter, it’s creating a bigger insulating layer to trap body heat, so that it doesn’t cool off as quickly.
To replace their feathers on a regular basis (to remove damaged or correct for lost feathers), birds undergo a process called moulting. Depending upon the species, this can happen all at once, be staggered over the course of a year, or happen gradually over several years. Many species undergo moulting during breeding season, to show off their flashy plumage.
Moulting is regulated by the pineal gland and circadian rhythms in most birds, though in pet birds, a somewhat-constant slow moult (punctuated by one or two “big moults” a year) is found, as a result of artificial lighting.
Illustrator and animator Anna Taberko continues to produce lovely kaleidoscopic animations that depict the blooming of flowers, the evolution of animals, and the flight of bees. Most of her pieces begin life as traditional hand-drawn cel animation before being digitized and turned into sequential loops.
For a brief time in the Permian period, humans evolved wings and flew all over the world. We lost them from atrophy after humankind stopped flying, likely due to the nuisance of the TSA. (Triassic Security Administration)
How did feathered dinosaurs finally take to the air? When did they become birds? This dramatic transition didn’t happen all at once, as Dinosaurs Among Us demonstrates. The evolution of feathers and flight-ready brains was just the beginning. And those awkward in-between stages include some of the most fascinating animals that ever lived: bushy, feathered tyrannosaurs; birds with lizard-like tails, teeth and claws; and even some small, leaping creatures with four wing-like limbs.
How did feathered dinosaurs finally take to the air? When did they become birds? This dramatic transition didn’t happen all at once, as the new exhibition Dinosaurs Among Us demonstrates. The evolution of feathers and flight-ready brains was just the beginning.
This early almost-bird, named Anchiornis huxleyi, appears right on the cusp of flight. Its feathered proto-wings couldn’t have kept it aloft for long, but they might have provided enough lift to help it leap to safety, pounce on prey, parachute down from heights, or run up steep slopes. Whatever the function of these early wings, they represent one of the last evolutionary stages before true modern flight evolved.
Alan was only fifteen when John started taking rotations on Thunderbird 5, and it’s alarming just how badly he’d missed his big brother. There’d been a hole in the family again, and it had reminded Alan painfully of the space where their mother used to be.
He hasn’t ever told him so, but John’s probably Alan’s hero. It’s funny, because it ought to be Scott. Scott’s the family’s other hotshot pilot, Scott’s the natural leader, Scott has the same charisma and magnitude that their father has, but in a more approachable package. John’s a lot less exciting, a lot quieter, a lot more thoughtful. John with his books and his telescope and his eyes always looking skyward. But when their father vanishes, it’s John Alan starts to lean on, more than anyone else.
It’s three in the morning on the first day of 2060, and Alan’s eighteen years old. He’s lying on his back, outside in a loungechair by the pool. He has one of the portable holocomms in his lap and a view of the stars overhead, clear and bright and indifferent to the newness of the year. It’s 2060, and Alan gives John a call.
“Happy New Year, little brother,” is the greeting, and John smiles when the connection blinks on. “Shouldn’t you be in bed?”
“Shouldn’t you?” Alan counters, though through a poorly timed yawn. “The stars are nice tonight.”
“Dymaxion sleep cycle, Alan.” John’s head turns and Alan can tell he’s looking out at the same dark sky. “But you’re right about the stars.”
Alan yawns again. “When’s dawn?”
“For you? About two hours from now. You really ought to get some sleep.”
“Yeah yeah. But, I had an idea though. It’s a pretty good idea, I wanted to call you about it. You’ll like it, promise.”
John arches an eyebrow at him and Alan cracks a grin. “Let’s hear it, and then you go to bed. It’s a bad way to start the year off, with sleep deprivation. Scott’s going to chew you out.”
“You let me worry about Scott. Okay. Here it is, though: what’ve you got planned nine years from now?”
This gets a bewildered blink out of John. “Uh. Hadn’t really thought about it too hard. I guess I’d like to try and do another doctorate by correspondence, maybe write that book on the evolution of orbital flight mechanics, maybe have a major overhaul done for ‘5…why?”
Alan grins. “We should go to the moon.”
And John lights up, exactly like Alan knew he would. “For the Apollo 11 centennial! Oh man. Yeah. Oh wow, we definitely should. Can ‘3 land on the moon?”
“If it can’t now, it will in nine years!” Alan answers, beaming. “Wouldn’t it be great, though? I wonder–I hope they don’t…I don’t know, do you think it would be all crowded? They wouldn’t throw a party or anything, that’d ruin it.”
“Yeah, that’d be terrible. I don’t know. I wonder if there are any plans. I know some guys at NASA, I’ll ask around. We should definitely go, if it’s allowed. I’m not actually sure who’s in charge of the moon. World Heritage, maybe. Er, Lunar Heritage? Anyway, I’m glad you thought of it.” John pauses and his expression grows slightly melancholy. “You’ll be twenty-seven.”
“Good math there, bro. Putting the astrophysics degree to work.”
“Shut up. I’m twenty-seven. In my head you’re still twelve. That’s…that’s weird, Al. Are you still going to want to hang out with your boring, nearly-forty-year-old brother? With the astrophysics and the book on suborbital flight mechanics that no one’s going to want to read?”
Alan sits up and frowns at the hologram of his brother. “Jeez! John. Of course I will. You’re the only one who’d care, anyway, About the moon landing.”
John chuckles, “I think maybe at least a few other people might care. Just a couple, you know.”
Shrugging, Alan waves this away dismissively. “Well, you’re the only person I know who’ll care about it right. You’re not boring, John. And I’ll read your book! Maybe the time I’m twenty-seven I’ll even understand it!”
“Heh. Yeah, maybe. If you get enough sleep and do your schoolwork.”
Alan rolls his eyes, “And I just said you weren’t boring. Jeez, John. I guess you’re gonna tell me to go to bed?”
“It’s your boring big brother’s job to tell you to go to bed,” John answers sagely, but he’s still smiling. “Thanks for calling, Alan. Nine years to the moon, then?”
“Sounds like a plan.”
John holds up a hand and Alan, long familiar with the gesture, holds up his own to mirror it. “Sounds like a promise,” his favourite brother agrees. “Happy New Year, Alan.”
Yeah, 1992 was a crap year for non-avialaen dinosaur discoveries… and avialaen dinosaur discoveries. I gotta scrape at the barrel for this. Still, Sinornis is a pretty cool dinosaur, all things considered. It lived about 135 million years ago, in the Valanginian age of the Early Cretaceous. It was found in the Jiufotang Formation at Liaoning, People’s Republic of China. It was about the size of a sparrow, and it was a transitional form between the very primitive early bird Archaeopteryx and modern forms. It lent much insight into the evolution of flight in modern birds, since Archaeopteryx did not have many of the features of modern birds with regards to flight and perching. It, like many early birds, had a mouth fully of teeth; most of its advanced characteristics were related to flight and perching. Based on its breastbone and shoulder structures, it was capable of flight similar to modern birds (and had the muscles necessary for it;) it had modified wrist bones that would allow the wrist to bend sharply back to tuck the wings during flight or rest. It had reduced claws, and small hands with a steady middle finger to allow for flight feather anchorage. It had separate finger bones, well adapted for flight, which in combination with its small form made it easier to fly. It was also capable of perching and climbing. It lived in a primarily arboreal habitat, and probably inhabited an ecological niche similar to sparrows.
How did feathered dinosaurs finally take to the air? When did they become birds? This dramatic transition didn’t happen all at once, as the new exhibition Dinosaurs Among Us demonstrates. The evolution of feathers and flight-ready brains was just the beginning. And those awkward in-between stages include some of the most fascinating animals that ever lived: bushy, feathered tyrannosaurs; birds with lizard-like tails, teeth and claws; and even some small, leaping creatures with four wing-like limbs.
“During the first years of the sixteenth century, Leonardo da Vinci made careful observations of the Black Kites, larks, and other species common to the Italian countryside, jotting down his ideas in a private notebook that came to be called Codex on the Flight of Birds. Leonardo’s designs for flying machines included a now-famous illustration of a primitive helicopter, as well as a flapping Icarus-style flier, but the most important pictures in the book may be a series of small birds sketched casually in the margins. They look like pigeons in flight, showing a variety of postures and depicting the birds with lines of air passing under and over each wing. Combined with his text on the "thickness” and “thinness” of air, these pictures make plain that Leonardo had begun to intuit the importance and function of airfoils.“
Thor Hanson, Feathers: The Evolution of a Natural Miracle.
Ricardo the lizard is very much aware that the next step in evolution involves flight, and since he hates his tank he has no qualms in speeding up the process by ignoring the 4 feet fall and jumping to the floor. Nico has had to shadowtravel across the room more than once to catch him. No matter how much Nico scolds the lizard afterwards, Will loves to point out that Ricardo ends up getting what he wants: a ride on Nico’s shoulder for the rest of the day.
Will ends up putting a pillow under the tank, because they don’t get the flying practice to really stop.
seeing as how flight has evolved seperately like 4 time, what do you think the most likey candidate for it to happen to next would be?
This is a weirdly complicated question, if only because I’m not usually one to mess around with speculative evolution. But I can tell you that the very first thing that would have to happen for something else to evolve flight would be a mass extinction.
Realistically, most of the specialized fauna alive today would also vanish if a mass extinction event that cleared the skies were to occur, so whatever developed flight next wouldn’t likely be from a species that is immediately recognizable (looking at you, THE FUTURE IS WILD).
THAT BEING SAID, in order to answer your question, let’s just pretend birds and bats went extinct suddenly but everything else was fine. Loads of flying bugs and fruits and junk to eat, places to nest, etc
Since evolution is a series of stages of momentary beneficial adaptations - aka, each step in the evolution of flight isn’t an actual step towards an “end goal” of flight, but rather a step that allowed a species to survive better with that step - it’s likely that the next into the air would be an animal already adapted for gliding or arboreal lifestyle. Powered flight is basically exploiting the niche of “the floor is lava”, so adaptations for living off the ground would make it more likely to occur.
I’d say that gliding mammals such as colugos or flying squirrels have a solid basis for taking up the torch - they’ve already got a significant patagium* connected to a limb that could become something capable of a powered downstroke, which would place them quite firmly at the top of my list of personal nightmares
That being said, I would personally prefer to see a flappy little amphibian evolve from one of those gliding frogs, or flying fish doing the reverse of penguins and taking up powered flight to catch bugs. The dream is, of course, the return of giant flying arthropods, but unless a REALLY significant mass extinction occurs, vertebrates are still better at getting big.