23
$\begingroup$

Consider an earth-like world without any flying species.

What could be the possible (I'm looking for a physics or chemistry/biology answer) cause of this?

Set aside trivial solutions as "random mass extinctions" and so on, I am willing to accept an answer that especially targets flying beings.

$\endgroup$
  • 3
    $\begingroup$ The reason that flying evolved in the first place was because at some point, it was beneficial to be able to fly. Maybe if you removed the benefit of flying for early evolution, then it would never happen? As far as I can tell, the first flying species were insects back in pre-history. Birds evolved over a very long time from dinosaurs. Both of these evolved to fly for different reasons, so removing these two reasons would do it. I don't have enough research to give a full answer for this though, so I'm just giving an idea to other answerers. $\endgroup$ – Aric Aug 21 '17 at 11:25
  • 10
    $\begingroup$ For the longest time throughout evolution there were no flying animals on earth. Could you comment on that fact? Life started in water not in the air and it took billions of years to learn flying. It could just not have happened without a "chemical reason" for it. By earth-like, I assume you mean same atmosphere/pressure/gravity and so on? No atmosphere of course would be a solution for example. $\endgroup$ – Raditz_35 Aug 21 '17 at 11:31
  • 1
    $\begingroup$ By no atmosphere, I'd have to hypothesize a planet small enough to retain one, but at that point I don't think life would be possible at all. Yes, I do mean with similar earth conditions: atmosphere / gravity, etc. $\endgroup$ – Noldor130884 Aug 21 '17 at 11:32
  • 2
    $\begingroup$ Noldor, you are asking two questions here. Your title asks is a world without flying animals possible while the body asks how could there be no flying animals in a world. It is usually better to ask only one question per post. $\endgroup$ – Bellerophon Aug 21 '17 at 12:47
  • 1
    $\begingroup$ Consider the difference between 'flying' and 'swimming'. Life on earth "heavily" (pun intended) reflects its water-based origins. Creatures sprung from a primordial soup of gasses may have entirely different categories of movement $\endgroup$ – Cireo Aug 22 '17 at 0:20

14 Answers 14

4
$\begingroup$

The following stretch what you mean by "earth like" to the fringes of our world, but might be doable.

Option 1: Penguin Planet

We know that some birds -- penguins -- went flightless in order to swim better and eat fish, near the Antarctic. It is plausible that an ice planet, with most of its behavior happening inside the oceans, penalizes flying beasts too much relative to the amount of additional food they can get. The only organisms that survive outside of the ocean are those which live in burrows in the ice and hunt in the ocean, making it terribly inefficient to fly.

Option 2: Irradiated Desert Planet

The magnetic field is weaker, the planet is heavier and drier, and the sun is perhaps bigger and bluer and we are a bit further out to compensate. This is a very speculative possibility of tweaking a lot of different parameters a little bit to get a similar-but-very-different Earth.

The idea is that the candidate atmosphere has a much weaker ozone layer and is more transparent to carcinogenic light -- UV, X, and gamma rays all have photon energies which can break typical chemical bonds. However, there is a possibility that this is mediated near the planet's oceans and surface because the surface is heated a bit more than Earth's usually is (which requires a bit more gravity) , causing air currents to be much stronger and storms rage over the planet.

The idea is that the experience "on the ground" is one of a perpetual smoggy haze mixed between fogs and dust, somewhat obscuring direct sunlight; the hope is that this provides protection from the carcinogenic radiation close to the planet's surface. There would still be sheltered places -- caves, canyons -- which see the development of flight, but it would no longer be a worldwide phenomenon.

So this idea is to hit the birds and insects with a triple or quadruple whammy: yes you can hypothetically fly but (a) you'll be more likely to get cancer and (b) you'll not be able to see your prey and (c) you'll have to ground yourself for cover anyway when the daily hurricane blows through and (d) your bones have to be even lighter and more frail to resist the extra gravity.

In response to these, perhaps flying per se is no longer a common design goal, but perhaps gliding is more prevalent. One can imagine membranes like sugar gliders have, or one can imagine that lighter insects throw up a "kite" of spider-silk and "sail" to distant locations like spores and such do.

$\endgroup$
  • 1
    $\begingroup$ As much as I appreciate every other answer, I think this fits the most to what I was looking for... Besides, how could I not reward "Penguin Planet"!? $\endgroup$ – Noldor130884 Aug 24 '17 at 6:00
39
$\begingroup$

The first flying insects appeared (as far as we know) in the Devonian, some 400 million years ago. Before that there were no flying animals. So not only is a world without flying animals possible, our own Earth was such a world for more than 90% of its history.

The catch is that flight emerged as a life strategy almost as soon as there were animals living on land... And there are flying fish too. (Yes I know that flying fish glide.)

$\endgroup$
  • 4
    $\begingroup$ yes, and before about 500 million years ago (when the first fish appeared) life on earth wasn't very interesting. $\endgroup$ – Octopus Aug 21 '17 at 19:12
  • 2
    $\begingroup$ @Octopus: Are you really sure? I guess it depends on what one considers interesting. Many paleontologists would be ecstatic to find an early Cambrian fossil deposit. $\endgroup$ – AlexP Aug 21 '17 at 19:15
  • 5
    $\begingroup$ Well of course, but another 100 million years is only 20% farther away than 500 million years ago. It gets less and less interesting the farther back you go--interesting, as in an Earth-like variety of creatures. $\endgroup$ – Octopus Aug 21 '17 at 19:43
  • 4
    $\begingroup$ @Octopus technically, Earth has always had an Earth-like variety of creatures... $\endgroup$ – Socratic Phoenix Aug 22 '17 at 17:08
  • 2
    $\begingroup$ @Octopus, to paraphrase a humorous math proof, consider the set of all uninteresting life on Earth. One of these organisms must have appeared before the others, making it interesting. This is a contradiction, therefore the set of uninteresting life is empty. $\endgroup$ – Poisson Fish Aug 22 '17 at 17:44
28
$\begingroup$

Discounting the problematic flying fish, flight has evolved 4 separate times that we know of.

  • Insects, 400 million years ago
  • Pterosaurs, 230 million years ago
  • Birds, 150 million years ago
  • Bats, 50 million years ago.

Given that we are considering "an earth-like world" with similar gravity and atmospheric composition, there is one one common denominator to the 4 events, and that's evolutionary pressure/natural selection.

At some point it became advantageous for each species to develop flight, the ones who could glide and flap succeeded, the ones who could glide and flap and fly better than the others fared even better.

Other than evolutionary pressure there's no one thing you could remove that would stop flight evolving at some point, and if you remove that then evolution isn't going to happen.

You could say flight hasn't evolved yet, but consider the young spiders that spin strands of silk into the wind until the wind picks them up and moves them along like seeds, and some plants figured out how to glide a long time ago, "flight" is ubiquitous in nature. Given the number of things that almost fly (time to mention the flying fish here) true flight is only ever a couple of adaptations away.

Evolution of flight is an excellent source on the subject

Life will find a way . . .

$\endgroup$
  • $\begingroup$ Well put. This answer will be better if it suggested some means for "removing the evolutionary pressure". $\endgroup$ – G0BLiN Aug 21 '17 at 14:35
  • 1
    $\begingroup$ @G0BLiN: But that's the problem with the question, remove the evolutionary pressure and remove evolution, your world may not have flight, but it will be populated by very boring bacteria (as was the earth for billions of years). $\endgroup$ – Binary Worrier Aug 21 '17 at 14:40
  • 2
    $\begingroup$ it's not necessary to remove all evolutionary pressures - just make flying something not so beneficial as it is on earth - e.g. have some kind of airborne hazard which becomes worse the further you are from the surface (lighter-than-air poisonous gas, microscopic flesh-eating parasites, etc.) or something which makes glide and rudimentary flight too risky to allow them to evolve to better flight (e.g. a very common 'sniper' predator with some kind of ranged attack, taking out anything dumb enough to jump)... You get the idea. $\endgroup$ – G0BLiN Aug 22 '17 at 12:56
  • $\begingroup$ (cont.) My point is that you just need some kind of counter pressure for this to work - there's no inherent problem with the OPs assumptions. $\endgroup$ – G0BLiN Aug 22 '17 at 12:56
  • 2
    $\begingroup$ @G0BLiN: Call it lack of imagination but I can't come up with a reasonable solution. By all means post an answer with just such a mechanism. $\endgroup$ – Binary Worrier Aug 22 '17 at 13:03
8
$\begingroup$

Sort-of very thin atmosphere is a possible background for this scenario. Assume there is sufficient oxygen to support some life but it's too thin to support flight. Anyway, flight would demand much energy and a thin atmosphere makes it worse. Animal need a much greater lung capacity and that would make them heavier too. Don't make it too thin, though: Water's liquid state has a narrower range. At 100 mbar (1/10 sea-level pressure) water evaporates at 50c which is reasonable as most places on Earth are not as warm. Check water phase-diagram, in case your scenario involves water-based life breathing oxygen.

Wind-borne pollination is still possible, but flight is more difficult.

$\endgroup$
  • 2
    $\begingroup$ An "earth like world" is specified in the question, thinning the atmosphere this much pushes that requirement too far imho $\endgroup$ – Binary Worrier Aug 21 '17 at 13:35
  • $\begingroup$ Oh yes you were before me with the idea I see now. Sorry about that. $\endgroup$ – mathreadler Aug 21 '17 at 18:28
  • 6
    $\begingroup$ There's not much inherently wrong with removing half the nitrogen from the atmosphere. $\endgroup$ – Joshua Aug 21 '17 at 19:30
6
$\begingroup$

As other answers say, flight emerges due to evolutionary pressure and advantage. Since you can't mechanically prevent flight being workable, you would need to remove its advantage or have a recent and somewhat selective mass extinction that affected fliers.

For example, suppose that the terrain was such that a flier wouldn't benefit at all from flying, for some reason, then we can expect flight not to arise. Or suppose all fliers became ground dwellers due to giantism, or only ground dwelling fliers survived due to volcanism in the very recent past that specifically affected fliers above non fliers (due to toxins in the air that due to climate didn't reach ground level)?

The problem is, it feels contrived right now. I can't think what would make ground travel so strongly preferred as to completely remove the odds of at least some flier benefiting, or radiative evolution explosively reoccupying the niche. And global atmospheric disruption would have much greater impact than it sounds like you want.

$\endgroup$
  • 2
    $\begingroup$ +1: Exactly, as soon as you have something "jumping" to get away from a predator, you have an evolutionary arms race that can, in time, develop into one or both trying to fly. $\endgroup$ – Binary Worrier Aug 22 '17 at 13:38
3
$\begingroup$

Make flying so expensive that it's not worth the cost. For example, by very strong and unpredictable winds. But such conditions will significanlty affect all other life beings. Plants would be low and robust, animals either heavy or having always strong grip to surface or plants.

Higher gravitation would also make wonders. While it would not make flying impossible, it would reduce the size of the animal where flying is viable. I suppose you don't consider microorganism floating in air as 'flying animals'. Anything too small to see could be ignored in your storyline.

$\endgroup$
  • 1
    $\begingroup$ "the young sjurko saw the predator and began to move away, just then a killer-sorroco blew up. The predator hunkered down and dug in, the young sjurko wasn't so lucky and found it's self spun up into the air. However after traveling some distance the killer-sorroco blew out, dropping the sjurko nicely on the ground. 'Phew!', it thought, 'that was a lucky escape, I wonder if I can do that again' and ambled off to find it's troup". Fast forward 100k years and you've have descendants of the sjukro flying about the place :) $\endgroup$ – Binary Worrier Aug 22 '17 at 14:08
  • 1
    $\begingroup$ Higher gravity actually makes flying easier because it makes the atmosphere denser. $\endgroup$ – Jack Aidley Aug 22 '17 at 19:46
2
$\begingroup$

Hmm.. some thoughts:

  • a layered Athmosphere with a deadly layer in ca. meters high wich is poisonous or is not breathable. But this has other impacts.

  • SciFi Solution: Space-based system which kills anything flying (to prevent anything to leave the planet?)

  • Fantasy Solution: one flying Species (Dragons?) which kills any other flying creature.

  • since you asked for a biological explanation: what if there is a special biologic difference which leads to creatures that cannot move their arms/wings very fast? As far as I rmember, flying Insects and Birds fly by moving their wings fast - if you make that impossible, you dont have flying Creatures anymore.

All Ideas have great Impacts on the World, but maybe there is one for you..

$\endgroup$
  • 1
    $\begingroup$ +1 for actually trying to answer the question. However given fluid dynamics the first is difficult to be plausible. The second has been done (Richard Morgans Orbitals around Harlans world), The third contradicts the question (a world with no flying creatures). The last is plausible, a biological set that consumes oxygen inefficiently (or exists anaerobically) would need to use energy sparingly, or rest and store energy for movement . . . $\endgroup$ – Binary Worrier Aug 22 '17 at 13:12
  • 2
    $\begingroup$ . . . Still it doesn't stop the evolution of lighter-than-air flight, or creatures developing an aerodynamic wing which provides lift with enough wind. Life finds a way. $\endgroup$ – Binary Worrier Aug 22 '17 at 13:12
  • 1
    $\begingroup$ I love this game, thanks for playing. Air bladders and sacks are used by some fish, and things like Portuguese man o' war - Wikipedia, it's conceivable for a creature to split water into hydrogen and oxygen and store the hydrogen for flight. A flexible wing (I'm imagining something like a spoiler on a F1 race car), which can be warped with little effort could provide controlled flight with very little wind, and/or ground effect. I love second guessing evolution :) $\endgroup$ – Binary Worrier Aug 22 '17 at 13:27
  • 2
    $\begingroup$ Also all bets are off when you add symbiosis into the mix, consider some enterprising land mollusk that evolves to exploit something like the Alsomitra macrocarpa seed, there's a flying mollusk right there! $\endgroup$ – Binary Worrier Aug 22 '17 at 13:30
  • 1
    $\begingroup$ another thought: ballonlike creatures filled with highly flammable hydrogen can be very INTERESTING.. (boom) $\endgroup$ – Julian Egner Aug 23 '17 at 7:21
1
$\begingroup$

If you remove flying creatures you will affect your planet's plant ecosystem.

Flying animals(insects) are very important for plant pollination and without it the plants couldn't reach the ecosystems outside their emerging points and as a result there wouldn't be a evolution of the plants by surviving in different environments and cross-mating with the adapted plant types. Every plant would be confined in a small area because of the lack of reliable seed transportation(insects) and a change in the environment would kill all this weak, non-evolved plants. It wouldn't be possible to have a stable life on this planet.

Some resources:
Bees Matter.
The importance of Pollinators.
Role and Importance of Pollinators.
University of Minnesota Research

Flying creatures have a great impact on the plant ecosystem and if you move them out of the equation through some scientific explanation, you should redesign the flora and the fauna of your entire planet from the beginning.

$\endgroup$
  • 1
    $\begingroup$ Can't we just say that insects (or whatever) crawl from plant to plant and the wind does the rest to make everyone's life easier? You know for the sake of a good focused and relatable story. Respect the bees and so on, yes, but maybe that particular world has other issues right now $\endgroup$ – Raditz_35 Aug 21 '17 at 12:22
  • 3
    $\begingroup$ I think your answer is a) off topic b) goes way too far and you cannot possible support c) "It wouldn't be possible to have a stable life on this planet. ". I also think it is d) trivial to point out that major changes to the ecosystem will change the ecosystem and might be better suited for a comment if you are worried about bees. I don't think he actually wants to e.g. terraform Mars, he just wants to have some fun with his world $\endgroup$ – Raditz_35 Aug 21 '17 at 12:34
  • 4
    $\begingroup$ Selection pressures will develop mechanisms to distribute pollen without the vector of insects and birds. This includes wind-borne pollen, pollen projected forcefully, and attractants to lure animals to go from flower to flower. A good answer. $\endgroup$ – a4android Aug 21 '17 at 12:38
  • 2
    $\begingroup$ Doesn't answer the question that is asked. Or rather, answers the title but not the body of the question which is how could a world like earth have no flying animals. $\endgroup$ – Bellerophon Aug 21 '17 at 12:41
  • 1
    $\begingroup$ Flying creatures are important only because plants had time to evolve to exploit flying creatures. Without flying creatures, no plant would evolve to require them in the first place. Besides this, there are lots of errors in your logic, eg coconut palm does spread without any creatures, by floating seeds and burr exploits land animals for that purpose. Pollinating insects don't have considerably larger range than wind pollination, it's the efficiency that's much better. $\endgroup$ – Agent_L Aug 22 '17 at 9:49
1
$\begingroup$

I think it's possible that in a flat world (no trees, no mountains, no hills) there would not be the necessary environment pressure for the flight trait to appear.

Think about it, most flying animals start first as gliding animals, that trait permitted them to save dips (jump from one branch to another) and escape from a predator. If no dips exists, there's no use in gliding, and as I see it, gliding needs to come first so flying trait can develop on top of it.

$\endgroup$
  • $\begingroup$ Well not really, in fact you could develop long jumps or flight to escape predators or whatever... $\endgroup$ – Noldor130884 Aug 23 '17 at 5:43
1
$\begingroup$

I saw a documentary, more or less realistic, where insects developed areas of the bodies with increased surface area to lose heat, then were able to jump further( proto-wings helping this) by "flapping" their proto wings, and a time went on, the wings were bigger and they learned how to fly. Perhaps your planet has no need for animals to lose heat?

$\endgroup$
0
$\begingroup$

If you consider removing atmosphere to still be sufficiently earth-like, then wings would not have anything to grab onto, propellers would not work either as they work by grabbing hold of air to create a push forward. The animals would need something like jet-engines or rocket pads to fly.


Now maybe that would still not be impossible since in fantasy and science fiction you have things like dragons who breathe fire and stuff. Maybe an inverted dragon species which farts flames which create a jet propulsion could still fly in such a scenario.

$\endgroup$
  • 2
    $\begingroup$ Rocket-asses aside, lighter-than-air flight is a more reasonable path for evolution of flight to take in a thin atmosphere. Also see Errol the Swamp Dragon $\endgroup$ – Binary Worrier Aug 22 '17 at 6:59
  • 1
    $\begingroup$ If you remove the atmosphere then life couldn't be supported. $\endgroup$ – EKons Aug 22 '17 at 9:29
  • $\begingroup$ Not necessarily, maybe the creatures can land and eat stuff / drink from oceans to build up a fuel reserve. Not sure they even need oxygen, but if they do maybe they can get it some other way than breathing. $\endgroup$ – mathreadler Aug 22 '17 at 9:40
0
$\begingroup$

How many worlds do you have? If you have a large enough sample size, you'll see all sorts of worlds with individual anomalies. If this is intended to be one planet in galaxy-spanning science-fiction setting a la Star Trek, maybe it's the one and only world where no flying life forms are known to have evolved, just by the vagaries of natural selection not hitting on that particular strategy.

In a nutshell, the mechanism that targets flying creatures in this answer is "probability".

$\endgroup$
  • $\begingroup$ Well, pondering on the plethora of flying animals that populate the Earth, I'd say that probability is against me :P $\endgroup$ – Noldor130884 Aug 23 '17 at 5:42
  • $\begingroup$ Flip a penny enough times and you'll get 1000 heads in a row. It isn't the individual likelihood, but the size of your population. $\endgroup$ – dspitzle Aug 23 '17 at 20:47
0
$\begingroup$

It could be an moon orbiting a very large planet with an ice layer on the surface and a salty ocean underneath like Europa.

$\endgroup$
  • $\begingroup$ But then it wouldn't be earth-like, since all the life would happen inside the ocean :) $\endgroup$ – Noldor130884 Aug 23 '17 at 5:41
0
$\begingroup$

It’s difficult to have animals and yet prevent them from exploiting an ecological niche without making your planet too non-Earth-like.

The physics of flying make it much easier for smaller animals. In fact for anything smaller than roughly insect size it become more of a challenge to not fly by being blown away. If you can prevent animals from being too small (I know not how) it will stop them from flying.

The ease of flying also depends on the density of the atmosphere. If the air is too thin, flying becomes impractical.

Trivially, if life could not exist outside of the water (cosmic radiation maybe?) then there could be no flight.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.