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View Full Version : Birds and insects, what would an ecosystem be without them?



beskeptical
2013-Aug-18, 02:58 AM
I'm writing sci-fi fiction about humans in the not to distant future who colonize a new planet that had an existing biosphere where life evolved similar to that on Earth sans primates. I'm not bothering with details about dinosaurs and don't need to explain a detailed chronology of how life the on the new planet evolved.

But I want realism in my not-of-this-Earth ecosystems. (I've asked some of this before so bear with me as I refine my questions in a new thread.) I'm struggling with lifeforms to include. Sea life, mammals, plants fungi, and microorganisms are some I will be using. I'm not as sure about insects and birds though obviously insects make up such a huge part of Earth's biosphere it seems like they would evolve again and again. And certainly locomotion through the atmosphere seems like evolution would repeat that category.

If birds and insects didn't evolve, what would be missing in the ecosystem that needed to be replaced by other organisms?

And would something else evolve to use the niche of bird-like vocals or do you think that is simply a coincidental evolutionary design? Bats, for example don't sing, do they?

This is about hypotheticals, and supporting scientific support for your opinions is of course not a requirement, just some reasoning for the hypotheses.


Thanks in advance.

ravens_cry
2013-Aug-18, 04:04 AM
You probably would have something filling the flying niche. Before birds, there was winged things, and they evolved
Capsicum rich foods wouldn't evolve, as they evolved as a defence against hungry critters with slower, more aggressive digestive systems with capsicum receptors. Birds, at least flying birds, lack both, the former evolving to help keep weight down. Not sure why they lack them, but they do.
A lack of insects would be interesting. Some creatures might evolve to fit that niche, like arachnids. It's possible bacteria could become much more aggressive decomposers as well. Wind and self pollination would be that much more common, and/or other small creatures would fill those niches.

beskeptical
2013-Aug-18, 04:19 AM
There are some ideas I can pull from that. I'll need to address pollination. And I'll look into the different digestion of insects vs herbivores. Thanks.

Jens
2013-Aug-18, 04:46 AM
One thought: the reason we don't find very small mammals may be because they would be attacked by insects, so without insects mammals might have gone into those niches (along with reptiles and what not). So you could have tiny nectar eating bats that would pollinate flowers.

beskeptical
2013-Aug-18, 06:09 AM
I like that. What about birdsongs?

Paul Wally
2013-Aug-18, 01:53 PM
It seems you don't want birds and insects, but then again you want it back in a different guise. Perhaps the question should be
what the ecosystem would be like without flying creatures. I don't think our biological classification system is very meaningful when applied to other planets.
What if you get a mammalian like creature with feathers, would that be a bird or a mammal? It would seem rather arbitrary to exclude only winged species with feathers. Why not exclude all winged species?

ravens_cry
2013-Aug-18, 07:15 PM
If it has mammaries, I'd call that a mammal. If you don't want fliers though, you'd have to explain why flying creatures never evolved. Given how many times it has happened, with even some fish and amphibians at least partly getting in the act via gliding and the advantage it can bring for escaping predators and catching prey, it would seem rather odd unless there was some extenuating circumstances.

beskeptical
2013-Aug-18, 08:18 PM
If it has mammaries, I'd call that a mammal. If you don't want fliers though, you'd have to explain why flying creatures never evolved. Given how many times it has happened, with even some fish and amphibians at least partly getting in the act via gliding and the advantage it can bring for escaping predators and catching prey, it would seem rather odd unless there was some extenuating circumstances.
I was going to have fliers. On Earth there are insects, bats and birds, so fliers are almost a given. I'm just trying to distinguish between things that are certain: means of locomotion, means to perceive the environment, means to reproduce, use energy, eliminate waste, and, things that are random.

chornedsnorkack
2013-Aug-18, 09:34 PM
There is a lot of uncertainty about how much early insects could fly. All Devonian insect fossils are wingless - yet it is argued that the first insect fossil, Rhyniogratha hirsti (it is a fossil of head, so no direct evidence of wings or no) had mouthparts resembling winged insects, not wingless insects.

There are several groups of flightless land arthropods: flightless insects (such as silverfish), flightless non-insect hexapods (such as springtails), land crabs, spiders, scorpions and multipedes. But since at least Carboniferous, flying insects are uniquely successful and diverse group because of flight. The other groups of land arthropods (and indeed invertebrates) have not independently evolved true flight and wings.

Vertebrates have evolved flight thrice - as much as thrice but ONLY thrice. Until the evolution of pterosaurs in late Triassic, throughout Carboniferous and Permian, insects could fly and vertebrates - amphibians and reptiles - crawled the ground, but none took flight. So, an ecosystem devoid of flying vertebrates is far from implausible - it has happened.

Biomechanically, low air density and pressure would disadvantage flight. Man would need oxygen, sure - but lower total atmospheric pressure due to lower stockpile of nitrogen, and higher percentage of oxygen, would be livable for man.

ravens_cry
2013-Aug-19, 12:20 AM
I was going to have fliers. On Earth there are insects, bats and birds, so fliers are almost a given. I'm just trying to distinguish between things that are certain: means of locomotion, means to perceive the environment, means to reproduce, use energy, eliminate waste, and, things that are random.
I was replying to Paul Wally in the comment above mine.

Delvo
2013-Aug-19, 12:48 AM
M automatic answer to "what if X didn't exist" tends to be "Y would be in its place", but I think what you're really going for is more like "what if the general type didn't exist". To deal with that, I must take some liberties like equating "mammal" to "large warm-blooded endoskeletal land animal" and "reptile" to their cold-blooded counterparts, so they can include completely alien animals that are neither mammal nor reptile.

Looking at it that way, I have to try to figure out how you're defining the "general type(s)" you have in mind. It looks like it could mean "flying animals", but the fact that you mentioned this twice...
would something else evolve to use the niche of bird-like vocals
What about birdsongs?...makes me think you might be trying to imagine what an environment might sound like without insects & birds making the sounds we're familiar with here.

The answer on sounds is that there's no reason why something else couldn't evolve to use them that way, but there's not much stopping them right now, either. The songs of the wild that you're used to hearing are mostly for attracting mates and helping them locate the caller. Other methods are available for that, such as using chemical signals or just being drawn to the same places where both sexes will end up near each other anyway. Whatever did use songs on another planet wouldn't need to sound similar to our singing animals, but it's pretty hard to imagine what other sounds you'd be hearing outside there instead.

On the flight issue, the first thing it makes me think of is pollination of flowering plants. Again, there are other ways to pollinate, and plants could still use wind or non-flying animals. But the easily visible, colorful things we normally call "flowers" are meant for insects and small birds, so they'd be absent without them. (Anything that cold reach them without flying would be either big enough to be prone to destroying them instead of merely picking up and dropping off pollen at them, or too small to transport the pollen very far.)

beskeptical
2013-Aug-19, 02:17 AM
It seems you don't want birds and insects, but then again you want it back in a different guise. Perhaps the question should be
what the ecosystem would be like without flying creatures. I don't think our biological classification system is very meaningful when applied to other planets.
What if you get a mammalian like creature with feathers, would that be a bird or a mammal? It would seem rather arbitrary to exclude only winged species with feathers. Why not exclude all winged species?It's not that I don't want them, not at all. It's that I don't want the reader asking, why would there be [insert species category] if evolution occurred on a different planet.

beskeptical
2013-Aug-19, 02:29 AM
M automatic answer to "what if X didn't exist" tends to be "Y would be in its place", but I think what you're really going for is more like "what if the general type didn't exist". To deal with that, I must take some liberties like equating "mammal" to "large warm-blooded endoskeletal land animal" and "reptile" to their cold-blooded counterparts, so they can include completely alien animals that are neither mammal nor reptile.

Looking at it that way, I have to try to figure out how you're defining the "general type(s)" you have in mind. It looks like it could mean "flying animals", but the fact that you mentioned this twice......makes me think you might be trying to imagine what an environment might sound like without insects & birds making the sounds we're familiar with here.

The answer on sounds is that there's no reason why something else couldn't evolve to use them that way, but there's not much stopping them right now, either. The songs of the wild that you're used to hearing are mostly for attracting mates and helping them locate the caller. Other methods are available for that, such as using chemical signals or just being drawn to the same places where both sexes will end up near each other anyway. Whatever did use songs on another planet wouldn't need to sound similar to our singing animals, but it's pretty hard to imagine what other sounds you'd be hearing outside there instead.

On the flight issue, the first thing it makes me think of is pollination of flowering plants. Again, there are other ways to pollinate, and plants could still use wind or non-flying animals. But the easily visible, colorful things we normally call "flowers" are meant for insects and small birds, so they'd be absent without them. (Anything that cold reach them without flying would be either big enough to be prone to destroying them instead of merely picking up and dropping off pollen at them, or too small to transport the pollen very far.)Warm blooded and cold blooded, I should definitely look at the roles those play in an ecosystem.

The idea is simply, what would the biology look like on an Earth-like planet where the life evolved differently than on Earth.

What was certain to be the same? I think you can include locomotion that fills the same niches that evolved on Earth: flying, walking, swimming, slithering, letting the wind and tides do the work; perceiving the world around the organism: vision in various areas of the EM spectrum, hearing, echolocation, chemotaxis or recognition; reproduction; energy utilization: respiration, consumption, metabolism and waste excretion; and I'm not sure what else.

But what would be random? Would birds and insects be a given or not? Certainly microorganisms would be a given. I can't imagine viruses would not evolve. But would insects and birds evolve or are they optional?

Swift
2013-Aug-19, 04:14 AM
The idea is simply, what would the biology look like on an Earth-like planet where the life evolved differently than on Earth.
I guess it would depend upon how Earth-like your Earth-like planet is.

If the gravity was higher, I would think it would tend to discourage flying creatures; the opposite if it was lower. But you might get some other effects - would you get taller trees in a low-G world, and so ecosytems would be more arboreal.

If oxygen levels were higher, you also might get more flying creatures and you might get more active creatures. Temperature may have a big effect on warm-bloodied versus cold-bloodied.

The type of star and its color spectrum might have a big effect - a star with more output toward the IR might mean that animals would have a different vision system.

Is there something magic about quadrupeds? Maybe hexapods are dominant among the land animals or fish.

On a different tact, as far as no insects, there are a lot of arthropods and other creatures (arachnids for one) that are similar enough to insects that people lump them together as "bugs". It would seem unlikely in an Earth-like planet, there wouldn't be something that was insect-like, even if it didn't have six legs. A small exoskeleton multi-legged creature seems likely.

ravens_cry
2013-Aug-19, 04:30 AM
It's not that I don't want them, not at all. It's that I don't want the reader asking, why would there be [insert species category] if evolution occurred on a different planet.
That could be said of pretty much any category though. There would be superficial resplendence,especially on Earth-like planets, (the laws of physics being the same everywhere) but I am willing to bet there would be enough macroscopic and microscopic differences to make pretty much all our Earth categories basically useless.

beskeptical
2013-Aug-19, 10:00 AM
That could be said of pretty much any category though. There would be superficial resplendence,especially on Earth-like planets, (the laws of physics being the same everywhere) but I am willing to bet there would be enough macroscopic and microscopic differences to make pretty much all our Earth categories basically useless.I would only think that likely if evolution was all random mutation and no selection.

beskeptical
2013-Aug-19, 10:16 AM
I guess it would depend upon how Earth-like your Earth-like planet is.

If the gravity was higher, I would think it would tend to discourage flying creatures; the opposite if it was lower. But you might get some other effects - would you get taller trees in a low-G world, and so ecosytems would be more arboreal.

If oxygen levels were higher, you also might get more flying creatures and you might get more active creatures. Temperature may have a big effect on warm-bloodied versus cold-bloodied.

The type of star and its color spectrum might have a big effect - a star with more output toward the IR might mean that animals would have a different vision system.

Is there something magic about quadrupeds? Maybe hexapods are dominant among the land animals or fish.

On a different tact, as far as no insects, there are a lot of arthropods and other creatures (arachnids for one) that are similar enough to insects that people lump them together as "bugs". It would seem unlikely in an Earth-like planet, there wouldn't be something that was insect-like, even if it didn't have six legs. A small exoskeleton multi-legged creature seems likely.So I wouldn't have to deal with too many issues, I've made the planet very much Earth-like. There are a few differences I'm working with but gravity and atmosphere are similar. And I specifically chose a star with the same spectrum as the Sun. There are active plate tectonics and a primary moon.

You don't think the efficiency of bipeds and quadrupeds when you get to a certain size animal played a role? Though an extra limb like a tail is an intriguing idea.

chornedsnorkack
2013-Aug-19, 10:32 AM
So I wouldn't have to deal with too many issues, I've made the planet very much Earth-like. There are a few differences I'm working with but gravity and atmosphere are similar. And I specifically chose a star with the same spectrum as the Sun. There are active plate tectonics and a primary moon.

You don't think the efficiency of bipeds and quadrupeds when you get to a certain size animal played a role? Though an extra limb like a tail is an intriguing idea.

And an idea present on Earth. Kangaroos are tripeds, and they are the dominant megaherbivores of a continent.

Although only since the recent manmade extinctions. Before these, the biggest herbivores were diprotodontids, and they were quadrupeds. Yet, the tripeds were present along the quadrupeds - including Procoptodon. Oh, and bipeds, too - emu and cassowaries.

Whatever the advantages of quadrupeds may be, this does not authomatically cause quadrupeds to evolve. Bipeds were alone for millions of years on New Zealand, yet the moa remained bipedal and did not evolve their wings back into legs.

Selfsim
2013-Aug-19, 11:44 AM
I would only think that likely if evolution was all random mutation and no selection.Self replicating systems select for complexification as opposed to simplification. This leads to dynamic stability.

Slower replicating systems become extinct, and end up evolving into much shorter-lived, more rapidly replicating entities.

Replication systems also evolve topologically divergent pathways. Because of this divergence, prediction is impossible. Speciation is an example of unpredictable divergence over time. A 're-run' of a known instance of evolution of a self-replicating system which results in speciation, will thus be entirely unpredictable, (as will be the divergent characteristics of its species). This divergence is specifically why we can retrace speciation backwards in time, (evidenced by the fossil record), to a single common point of origin.

The evolutionary outcomes of a replicating system on another 'Earth-like' planet are thus effectively, unknowable in advance.

Nick Theodorakis
2013-Aug-19, 12:39 PM
Evolution is also constrained by the developmental history of the organism. If the lobe finned fish that was the precursor to limbed animals was crawling around on 6 fins instead of 4, the dominant forms of land vertebrates might have 6 legs, and if any intelligent creatures evolved that had adapted the two most forward limbs into hands, they might well be speculating that 6 leggedness would be necessary for tool-using intelligent life to evolve, since it would be obvious (to them) that no creature would be stable on only two legs.

Nick

Swift
2013-Aug-19, 01:13 PM
You don't think the efficiency of bipeds and quadrupeds when you get to a certain size animal played a role? Though an extra limb like a tail is an intriguing idea.
I don't know. It is conceivable to me that there is an element of random chance in this also. Even given an identical planet, there is a certain amount of random chance in evolution.

And if you argue, no, there isn't, that given an almost identical planet to start with, you would end up the same way, then why don't you have insects?

mkline55
2013-Aug-19, 01:21 PM
For sounds, frogs might fill the void. They certainly do at times in my neck of the woods.

Colin Robinson
2013-Aug-19, 11:47 PM
That could be said of pretty much any category though. There would be superficial resplendence,especially on Earth-like planets, (the laws of physics being the same everywhere) but I am willing to bet there would be enough macroscopic and microscopic differences to make pretty much all our Earth categories basically useless.

I tend to agree. Resemblances due to those laws of physics may involve structures and functions, as well as appearance. But categories like insect, fish and mammal are unlikely to be workable.


If it has mammaries, I'd call that a mammal.

On Earth there are several groups of creatures that actively nourish their young, but only one group, the mammals, does so with a mammary gland distinct from the digestive tract.

In another Earth-like ecosystem, perhaps there may be no creature with such a gland. On the other hand, perhaps there might be several very different groups of creatures with glands that do that. What if there is one group with glands for suckling which has an insect-like exoskeleton, and another group of sucklers with gills rather than lungs, as well as a third group of consisting of feathered flyers who suckle their young?

Would we want to use the word "mammal" for all of them?


And an idea present on Earth. Kangaroos are tripeds, and they are the dominant megaherbivores of a continent.

Yes, the Australian continent is a good example of the range of results evolution can produce. And it is worth remembering how bizarre some of the Australian animals looked to the first European naturalists who examined them, just a couple of centuries ago. Especially the platypus, which was suspected as a hoax.

ravens_cry
2013-Aug-20, 04:10 AM
On Earth there are several groups of creatures that actively nourish their young, but only one group, the mammals, does so with a mammary gland distinct from the digestive tract.

In another Earth-like ecosystem, perhaps there may be no creature with such a gland. On the other hand, perhaps there might be several very different groups of creatures with glands that do that. What if there is one group with glands for suckling which has an insect-like exoskeleton, and another group of sucklers with gills rather than lungs, as well as a third group of consisting of feathered flyers who suckle their young?

Would we want to use the word "mammal" for all of them?
I'd probably start appending some prefixes in in that case, unless another feature was more definitive for the type, in which case I would pick that to help name them.

Delvo
2013-Aug-21, 03:48 AM
Warm blooded and cold blooded, I should definitely look at the roles those play in an ecosystem.Warm-blooded critters must eat more and can travel farther. That makes them more useful to plants for spreading seeds but also more harmful because they eat a lot of them. Practically every specialized trait possessed by a plant to interact with animals, both to keep the animals away and to attract them and use them, is associated with a warm-blooded one or a flying insect (whose ability to fly extends their range despite the fact that they're not warm-blooded).


Would birds and insects be a given or not? Certainly microorganisms would be a given. I can't imagine viruses would not evolve. But would insects and birds evolve or are they optional?Possible but very unlikely, to the point that if they did it would be bizarrely coincidental and, when we discovered them, they would probably fool us into thinking they had originated on one planet and somehow been transported to the other one.

The key is how many little details need to fall into place to fit the description. For the word "microorganisms", it's pretty simple: anything small enough will do, whether it has much in common with any Earthly microbe or not, so a lot of different things are included. "Virus" is similarly broad and inclusive. It doesn't take a long list of traits to make a virus a virus and not something else like a bacterium or tree or octopus: just a genome inside a protein shell, which gets inside a cell and makes more of itself using the cell's resources. That includes a lot of different kinds of viruses.

Now look at how specific the word "bird" is: gizzard, wishbone, nictitating membranes, lack of bladder, beak made of beta keratin (same stuff as their feathers and claws but distinct from the alpha keratin mammals use), feathers with secondary hair-like projections out from the central shaft lined with tiny hooks to hang on to each other, 4 kinds of retinal cone cells, no retinal rod cells, 3 or less forward toes and 1 or 0 backward toes per foot, loss of digits 4 & 5 and fusion of 2 & 3 on the arms, a list of other bone fusions or losses in other parts of the body, two-bone inner ear system, no outer ears, single intestine ending in a cloaca, calcification of eggshells, WZ chromosomal sex determination, one-way lung system with networks of air sacs before and after, extra ring of thin bone inside each eye socket, nitrogen disposal in uric acid, salt-impermeable skin, internal energy supply controlled by creatine as the instigator of adenosine triphosphate production... and that's leaving out a bunch of chemical and microscopic distinctions because my own knowledge of the subject is skewed toward large-scale anatomy, as well as a few things I could have included based on the present population but didn't for paleontological reasons, such as a lack of teeth or a bony muscular tail (some extinct critters which had them are called birds anyway)... and we could also throw in the equivalent lists of traits to define vertebrates, or chordates, as distinct from invertebrates or non-chordates, in order to establish a base concept of what "birds" have in common with things like "mammals" or "reptiles" that makes those the appropriate other critters to be trying to distinguish "birds" from in the first place...

Overall, the list of independent details that would need to coincide, for little or no apparent reason, in order to make some critters from another planet fit the Earthly concept of "birds", would probably have dozens or even hundreds of items in it if it weren't rushed and simplified like mine (and well into the thousands at a genetic level). And there's nothing in particular to cause all of those traits to end up together, when an alien critter could just as well have some of those traits in common with birds but alternatives for some of the others.

If what you're really after is just a simpler, smaller set of generic traits, like that the animal is in the same size range as (flying) birds and it flies, then that would include a variety of things that that I presume are real somewhere (because there are lots and lots of stars out there and things like that have already evolved thrice on just this planet) but which would in most cases not have most of those other traits in common with birds. Pern's "fire lizards"(1 (http://d202m5krfqbpi5.cloudfront.net/books/1298419242l/28541.jpg),2 (http://d202m5krfqbpi5.cloudfront.net/books/1336498847l/177938.jpg)), for example, would qualify. But the information I have right now doesn't tell me whether they'd fit what you have in mind, so, as the author, you should find or invent a word or phrase that's just vague enough to evoke what you're really thinking without unintentionally dragging too much Earthbound specificity around with it.

You might notice in the example above that the word "lizard" is used, and it could be associated with another long list of details like the one above for birds, but the addition of the word "fire" tells the reader that it's something else, being compared with real lizards only as a sort of analogy. It's also common with real species on Earth, such as the "mountain lion" and "panda bear" and "red cedar". So your name for generally bird-like alien critters could very well be based in some way on birds, as long as it's also distinct from just "birds".

Githyanki
2013-Aug-22, 02:28 AM
Birds and insects, what would an ecosystem be without them?

Precambrian.

chornedsnorkack
2013-Aug-24, 08:13 AM
Precambrian.

No - predevonian.

Insects and birds did not exist through Cambrian, Ordovician and Silurian.

Ilya
2013-Sep-04, 05:38 PM
No - predevonian.

Insects and birds did not exist through Cambrian, Ordovician and Silurian.
So there was a fairly long period in Earth history with abundant land life, and no flying organisms at all.

chornedsnorkack
2013-Sep-29, 04:38 PM
So there was a fairly long period in Earth history with abundant land life, and no flying organisms at all.

Not abundant or fairly long. Land plants appeared in Silurian, and they were not really abundant. Flying insects appeared sometime in Devonian - not clear when.