/sci/ - Science & Math

something about the bones having to become wider than they are long to support the bulk

that only really applies to mammals though

Any size limit has more to do with the animal supporting it's own body weight.

>>5590321
the body weight, potential energy or oxygen one?

>>5590331
I'd like to know about any of them.
I was under the impression however, that there was a single formula of some kind that meant no animal could grow past a certian size

>>5590337
I suppose there might be something like that at least for insects.

>>5590342
>>5590331
>>5590326
Can anybody elaborate on any of these? I've tried google but can't seem to find the right search term

>>5590342
I think insects happened to be bigger the more oxygen rich atmosphere of early earth. I believe it has something to do with how their breathing organs work, and the rather low content of our todays atmosphere prevents them from growing to a certain size.

>>5590375
*in

The surface area of an organism is x^2. (i.e. cm^2)
The volume of the same organism is y^3. (i.e. cm^3)
As an organism grows, the volume of it is increasing exponentially greater than the surface area, and there is a point when the surface area can not contain the volume anymore.
There is no law, its just physics and logic.

>>5590321
Either 02 efficiency (its the reason arthropods are smaller today, less 02 combined with an inefficient 02 distribution system=smaller organism), or a surface area:volume issue for thermoregulatory purposes.

Prof Brian Cox mentions it in a episode from Wonders of Life on BBC, but not sure which one...
http://www.bbc.co.uk/programmes/p012qczg
It would be a reliable source to quote.

>>5590375
Insects have an open blood circulation system which takes in air through "holes".
Larger insects would either need higher oxygen density or a lot more surface area as the volume increases.
Also, open blood circulation can't support larger animals, which puts an "upper bound" to the insect size, even if oxygen density was increased sufficiently.

>>5590321
http://en.wikipedia.org/wiki/Kleiber%27s_law

>>5590422
>>5590431
>>5590417

Is there a reason why everything can't be scaled up?
Is it theoretically possible for there to be a planet out there that's the same as ours, but everything is 1000 times larger?

>>5590445
>Is it theoretically possible for there to be a planet out there that's the same as ours, but everything is 1000 times larger?
Yes, if you consider that not all life has to resemble earth life of H20 CO2 NH2

>>5590445
Resources such as food an oxygen can only be absorbed through the surface, but the need for resources increases based on volume, not surface area. If you try to "scale up", volume increases MUCH faster than surface area. So you can't just scale something up & have it be exactly the same thing. For example, you try to scale up x10; the mouth is only 10 times larger, but it has to eat maybe times as much food -- it probably literally won't be able to eat that much.

>>5590321
Also the square-cube law. The relation between volume and surface area of the animal's outer covering. It will be crushed under the pressure exerted on its structure by its innards.

>>5590445
With lower gravity, more O2, and lower temperatures, maybe

>>5590417
that's horribly wrong and stupid.

1: you can theoretically make an endlessly large mushroom.
2: nothing prevents organisms filled with holes
3: there is not limit to the size of animals, only limits to certain kinds of animals' sizes.

What does xenobiology have to say about this? It seems pretty dependant on our gravity.

>>5590494
>mushroom
>animal

Get a load of this faggot.

>>5590525
to be fair mushrooms are more animal than plant

>>5590533
Mushrooms are 0% animal and 0% plant, and 0% is not greater than 0%.

>>5590534
They are closer to animals than to plants.

>>5590536
And they're even closer to fungi than animals. Funny how that works.

>>5590525
>>5590534
he is saying that they have more animal like qualities than plant ones. Not that they are part animal or part plant

>>5590485
I think this is the law i read about

>>5590494
Enlarging mushrooms is much easier than enlarging animals.

Mushrooms and animals mainly differentiate by the cellular structure.
Mushroom cells have a cell wall made out of chitin, while animal cells only have a soft cell membrane.
Many animals need a skeleton or exoskeleton, which also has to grow proprtionally to the body.
A giant mushroom would have notably sturdier build than an equivalent animal.

Mushrooms also gather nutrients through "roots", while animals need to eat other beings.
A mushroom can easily drain a comparably large area, while animals would have to eat plants or hunt constantly.

>>5590321
gravity

>>5590539
The point's going right over your head, isn't it?

>>5590417
x^3 is not "exponentially greater" than x^2.

>>5590570
the point is, you're a fucking idiot for comparing apple to rocks

>>5590540
Actually they have more plant like qualities than animal like ones, however they are more closely evolutionarily related to animals than to plants.

>>5590585
actually, they have more bacteria like qualities than animal or plant like ones.

>>5590589
That depends what you mean when you say "bacteria", going by the current phylogenetic meaning of bacteria, no, not even remotely fucking close, they're much, much closer to both animals and plants by pretty much any measure than to bacteria, were you perhaps confusing bacteria with protists?

>>5590598
the point is, is that it doesn't matter how fucking close they are. plants are not animals are not fungi. if they were closer to one than the other, then you'd expect there to be some evolutionary link between them, and there's not.

>>5590607
>if they were closer to one than the other, then you'd expect there to be some evolutionary link between them, and there's not.
But that's simply not true at all, there's an evolutionary link between any two species on the planet and the evolutionary link between fungi and animals is closer than between fungi and plants, I seriously suggest you read up on basic phylogenetics if you're not getting this concept.

>>5590494

>you can theoretically make an endlessly large mushroom.

I'm assuming you're talking about the underground mycelium net, and not the actual fruiting body - and in that case, your statement is approximately as profound and as relevant as saying "With enough space and the right resources, you can theoretically make an endlessly large forest."

>>5590642
there's nothing to read up on, you're wrong, and grasping at straws to try to get your ill-conceived point across

i've never heard of that, but consider the fact that the skeleton of a bird was found some years ago, it was so big that it ended a discussion on how big a flying creature could be at max
Also consider the fact that some other animal family might evolve, one that has an anatomy so different that it can basically become bigger. The biggest animals ever to exist are the whales, modern mammals, which are fairly recent compared to most other animal families

Of course, i'm just speculating and don't have enough knowledge to say more for certain

>>5590655
lol, okay buddy, not only are you wrong you have no understanding of elementary biology but have fun thinking your ignorance is knowledge

>>5590712

your point on evolution has nothing to do with whats' being talked about.

nice try though. I don't have to be a biologist to know your logic is shit.

>>5590321
You may also enjoy
http://en.wikipedia.org/wiki/Bergmann's_rule

You have to consider how different aspects of animal physiology change in relation to length.

Like how mass increases with volume, proportional to the cube of length, but bone strength is mostly related to the cross-sectional area of the bone, proportional to the square of length. This means larger animals need relatively thicker bones.

I think some whales are already at the size where they are 'crushed' under their weight on land, doing silly things to their internal organs, but don't quote me on that. The larger stress on bones is shown in how big animals like horses have to hold their leg straight when it contacts the ground during running. The whole bone thing only applies to things with bones, of course, but any land animal is going to need some supporting structure and there's reasons why exoskeletons aren't so useful in larger scale.

Of course, ultimately one limiting factor is going to be the sheer amount of food the damn thing requires (I guess this can be overcome), but there are of course other factors, I'm no expert on the subject.

In general, scaling works in ways that are not always obviously clear, and most organisms simply cannot be scaled up or down and remain functional. For some interesting reading, check this link:

http://fathom.lib.uchicago.edu/2/21701757/

or any other result from a quick google search related to the issue.

There was this site I once knew of, although I can't remember it now, explaining scientifically the reason so many b and normal sci-fi movies with growing/shrinking humans and animals couldn't actually happen. I wish I remembered it.

>>5590798

I think you may be referring to the link in

>>5590798

>>5590799

fuck it, i meant the link in

>>5590772

>>5590803
>>5590799
Yep! Thanks, man. I've been looking for that again for a while.

>>5590772
In regards to the food problem; i'm picturing an earth the same as ours, just a thousandx bigger. So the animal is 1000x bigger, and their prey is 1000x bigger.

Does it work? Someone mentioned gravity being a factor in how large something can grow, which makes sense as to why the blue whale is the largest mammal in the world; becase it lives in water

>>5591044
It does not work. The increase in volume will be much greater than the increase in surface area. So say that after scaling up, their mouth is 1000 times taller and 1000 times wider (1 million times larger overall), but their total volume and their food requirements are one BILLION times larger. Even though their mouth is a million times larger than before, it still wouldn't be enough let them eat a billion times as much.

You could redesign them so that their entire body was devoted to food intake, but then you'd have something fundamentally different.

>>5591044

Well, if the Earth is a thousand times bigger then gravity is going to be pretty intense. I'm not sure whether astrophysics has anything to say on whether such a planet would be feasible. I don't really know much about how an increase in gravity would affect things.

If we assume Earth gravity and organisms a thousand times bigger, they'll have a hard time getting materials strong enough to make their support structure withstand the forces involved. They do need some support structures if they want to move, I think. I would guess they wouldn't move anywhere fast without breaking something. Especially if you factor in the increase in gravity. I don't think any conventional animal as we know it could grow to such a size: possibly with an alien body structure and materials things could be different. Or they could be things that don't move around very much: huge plants and fungi do exist on Earth, they are among its oldest living organisms.

This is all speculative, of course, and I don't really have much to base my claims on. But look at animals on Earth: heavier animals get a definitely 'bulky' build. Think moving from a horse to a hippo to a rhino to an elephant.

>>5591070
Assuming they eat the same way do, or any of their biological systems are similar to ones known to us.

>>5590730
lol that's the thing though, its not being a biologist, im a fucking math major ive just taken intro level biology classes so i know you have no fucking clue what youre talking about

>>5591098
Well if their biological systems aren't at all similar to ones known to us this isn't science, it's blind speculation, obviously if there are 1000 ton living blobs of jelly its not the same as what were talking about

>>5591116
OP here.
I'm strictly talking about the animals we know of. So literally, say, an elephant that's 1000x larger.

I seem to have my answer though: a resounding no

/tg/ here, we often argue about how the giant spiders so many of us have in our games are physically impossible. thats why in pathfinder there is a giant spider enemy that is really just an excreted spider shaped shell moved around like a puppet by the hundreds of smaller spiders living inside of it.

also i remember some scientific rule of thumb about animal size often relating to enviromental temp because of the surface area thing. its why alaska has moose and florida has tiny dog sized key deer.

ITT: People do not know about the Cell.

>>5590337
Single formula?
A single, simple reason governing something as complex as the variation of animal body size?

You are fantasizing; there must many relevant factors to body size.

>>5590417
>there is a point when the surface area can not contain the volume anymore.

Uh... no, you just showed that you can ALWAYS calculate the surface area from the volume, not that one outpaces the other.

How could you imagine there is a way for these not to match?

>>5590417
10/19, would lel again

>>5590485
>It will be crushed under the pressure exerted on its structure by its innards.
Presumes no changes to the structure; why shouldn't there be?

>>5590431
>which puts an "upper bound" to the insect size,
Presumes no other changes to the animal of any kind. Why?


Any discussion of animal sizes should fairly split between a thread discussing a specific animal's max, and theoretical values as this seems to be asking.
GIven all the ways animal bodies can vary, and potential ways that can be perceived, there clearly can be no small set of factors; it would be a huge variation.

>>5590513
I would agree with this. But it also depends how much food there is, and probably an innumerable amount of other conditions that we cannot foresee.

>>5591181
Food, oxygen, and other resources can only be absorbed through the surface. If surface area increases 1 million times, volume increases 1 BILLION times. It becomes increasingly more improbable that the somewhat increased surface area can support the vastly increased volume in terms of resource absorption.

>>5591181
>>5591182
Obvious samefag is obvious.

>>5590676
I hate when people classify protists as being polyphyletic

>>5591044
>So the animal is 1000x bigger, and their prey is 1000x bigger.

This shows another of the limits: the range of prey for predators.

A large animal can be fed by small ones within range of both of their locomotive ability.
But the same is not true one step higher; there wouldn't be another large animal preying on that large one, because neither would have the range.

If you cannot reach your food, you die; such large animals would never evolve because almost everything works against giving them best-prospect chances at feeding.

>>5591222
Oops; but you are wrong; only one of those was me.
You because you can imagine something being true doesn't mean you have cause to.

>>5591213
correctm, of course -- but the post I replied to didn't say anything about feeding the volume.

It said that surface area CANNOT CONTAIN its own volume.
That is nonsensical.

Scientists used to think that nothing the size of a bumblebee could fly.

gravity.
i heard it's pretty sound.
it's just a theory though.

an animal cannot be larger at present than all the energy and matter available in our universe.
otherwise, given the resources and technology, you can build one whatever size you want.

So, the volume of an object is proportional to its length cubed, whereas the surface area of an object is proportional to its length squared.

So, in general, a larger animal will have a relatively large volume and hence a relatively large mass. This is why insects can lift several times their own weight.

>>5592224
What.

There are a lot of complex factors here, some on earth have been nutrition and oxygen levels.

>>5592224
And then these "scientists" just happened to discover flies, bees and bumblebees?

You are all fucking retarded, its the fact that because volume grows faster than surface area, in the ratios mentioned above. For earth-like conditions, larger animals have issues with heat dissipation and nutrient penetrance. Because of this same reasons, cells can only reach a certain maximum size, as functional healthy adult cells.

>>5590417

While this is 100% complete bullshit when applied to most animals it actually holds true for insects due to them breathing through their skin

>>5590321
it's just the energy consumption. The reason dinosaurs were huge is because they were lizards, so they didn't use as much energy as a mammal. Elephants are the biggest mammals and they need to eat all day long in order to survive. If there was an infinite amount of food then animals would be much bigger than they currently are.

I remember one of my earliest dreams, I must have been 3 or so.. was a row of giant octopuses 100x taller than a skyscraper marching silhouetted across the sunset horizon.

>>5592626
that was the reapers

oxygen in the atmosphere is a large contributor,

with mammals their bone matrixes arent strong enough to support anything too big

for invertebrates they have the support structure to handle large sizes but their method of oxygen intake is vastly inferior, and with the earths current concentration of O2, they would need to evolve a brand new way to absorb it.

>>5592617
Ok. So which land-dwelling species can theoretically grow the largest?

>>5592660
If given the right conditions, of course

>>5592660
By mass or length?

>>5592598
>>5592595
>>5592224

No, early physics didn't allow for the kind of wing movement that bees and other small insects used to fly.

Then we figured out better math, and it works just fine.

Stop perpetuating falsehood.

>>5592678
Either