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Based on an article by A. K. Dewdney ("Sharks and Fish on the Planet Wa-Tor"), this is a simple ecology simulation.

In this simulation, fish swim and reproduce while sharks swim, reproduce, and eat the fish.

About the parameters...

Breed Time: How old a fish or shark needs to be before it will reproduce. (On Wa-Tor, fish and sharks all reproduce by parthenogenesis, like amoebae.)

Starve: How long a shark can go without eating before it will starve to death.

Initial Population: The total number of each species with which to start the simulation.

World Size: The world wraps around so that, when a fish or shark swims off an edge, they come back on the opposing edge. The world can be anywhere from 2x2 to 20x15.

What parameters will provide a self-sustaining eco-system in which the sharks never hunt the fish to extinction but never starve to extinction themselves?

The original program Dewdney described in the article, back in the mid-1980's, used a simple text display in a grid with 0 . and * to indicate sharks, water, and fish.

Update: The simulation has been updated to remove the upper limit on world size. Very large worlds may cause the simulation to slow down but think about experimenting with the effect using larger worlds or long, thin worlds.
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:iconnechromicon:
Nechromicon Featured By Owner Jul 24, 2015  New Deviant Student Digital Artist
How clever.
Reply
:icondalek-who:
Dalek-who Featured By Owner Edited Nov 29, 2014
I was able to go 2459 time with the original settings.
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:iconhaoasakura16:
HaoAsakura16 Featured By Owner Oct 26, 2014  Student Traditional Artist
Sharks: Breed=10 Starve=5 In Population=30
Fishes: Breed=1 Population=120

Size: 40x20

They were alive (sometimes almost enxtinct, but still alive) for a few hours until I just stopped it D:
Reply
:icon101joee101:
101joee101 Featured By Owner Jun 14, 2014
I got An Infinite Cycle. Set:
Shark
Ini. Pop: 1
Starve: 1
Breed: Some really big number

Fish
Breed: 1
Ini. Pop: 4

Size: 2x2
Reply
:iconagv120395:
AGV120395 Featured By Owner Jun 6, 2014
perfect!
Reply
:iconmaxterandkiwiking:
MaxterandKiwiKing Featured By Owner Nov 22, 2013  Hobbyist Digital Artist
The first time I played, the sharks went extinct at 804 seconds.
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:iconkheelaia:
Kheelaia Featured By Owner Aug 22, 2013  Hobbyist Digital Artist
2014 seconds!
Reply
:icongonernow:
gonernow Featured By Owner Jan 14, 2013
Have you had any requests from fish scientists or biology teachers to do other simulations? This could be a very good learning tool.
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:iconsilverclawpetshop:
SilverclawPetShop Featured By Owner Oct 18, 2012  Hobbyist Artist
1629 seconds!
Reply
:iconroxie-the-charizard:
Roxie-the-Charizard Featured By Owner Aug 21, 2012
Very interesting. In my case sharks got overpopulated, the fish almost got excint, but then most sharks starved to death so fish started populating again. And then sharks got overpopulated again, and it became a big endless cycle.
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:icondetrimentality:
Detrimentality Featured By Owner Oct 30, 2011  Student General Artist
this is so cool
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:iconproudgeek8:
Proudgeek8 Featured By Owner Jan 5, 2011
it seems as if this could be rather useful for some science classes, because of the way it shows the basic predator-prey patterns (Predator rises, prey falls, predator falls, prey rises, predator rises......)
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:iconawes132:
awes132 Featured By Owner Aug 29, 2010
i parameters wich will make it last forever or at least that long that you cant watch it till the end
shark
ini. population 1
starve 1
breed 9999999 or something less but still incredible high
fish
ini. population = rest of tiles
breed 1
Reply
:iconsonicfan570130:
SonicFan570130 Featured By Owner Aug 15, 2010  Hobbyist Writer
Over 4000 seconds~
Fish:
Breedrate- 2
Original population- 120
Sharks:
Breedrate- 20
Starve- 1
Original population- 40
Size: 40 X 15
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:iconnaught101:
naught101 Featured By Owner Jan 29, 2010
Awesome.
Reply
:iconsonicfan570130:
SonicFan570130 Featured By Owner Aug 22, 2009  Hobbyist Writer
I think that I have success fully made an ecosystem that won't die!
Fish:
Breed rate: 1
original population: 550
Sharks:
Breed rate: 20
starve rate: 5
original population: 90
I'll stay 'til they die...
Reply
:iconveclock:
veclock Featured By Owner Oct 9, 2008  Student Digital Artist
what a perfect simulation! I've tried that, but the predator or the prey always died out... How did you do that?
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:iconeritnger1000:
eritnger1000 Featured By Owner Jan 14, 2008  Student Digital Artist
i dont get the point?>w<'
Reply
:iconjavamocha:
javamocha Featured By Owner Dec 31, 2007
one of the greatest biological simulations I've ever seen
amazing job
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:iconenyon:
enyon Featured By Owner Sep 10, 2007  Student General Artist
maybe you should make more things like this one :)
Reply
:icontpmjinx:
TPMjinx Featured By Owner Apr 4, 2007  Hobbyist Digital Artist
Time: 1500
15 sharks
450 fish

this is so cool! OH MY GOD!!!

I can't believe they've lasted so long!
I just changed the sharks to starve after a day and they're all thriving!

Shark's fluxuation: 13-110
Fish fluxuation: 44-550
(Fluxuations are approximate, just passed 2000 time)
OMG definite fave!

WOOT!
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:iconhaitien78:
HaiTien78 Featured By Owner Mar 16, 2007
very addictive and creative, thumbs up
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:iconincendiaryfluff:
IncendiaryFluff Featured By Owner Dec 2, 2005
I got my fish population up to 517 with the default parameters. That's 30 more minutes of my life gone. XD Good job!
Reply
:iconsharkoftheday:
sharkoftheday Featured By Owner Nov 26, 2005  Hobbyist Writer
This assumes that sharks eat as much as they possibly can, that if the resources are available they will eat every move. Anyway, that makes the system easy to manipulate. A single shark is placed in apopulation of 50 fish, it breeds every seven moves while fish breed after every 1 move. The shark starves unless it eats within 1 move. (Default size.) The population is self sustaining if it starts off well, but it moves so erratically (it either can't be real or is all too real). Anyway, the system just seems so easy to manipulate. With quick-breeding fish and quick-starving sharks its almost guaranteed to succeed.
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:icondovsherman:
DovSherman Featured By Owner Nov 27, 2005  Professional Digital Artist
That's a good point. But finding the "right" parameters doesn't necessarily mean simply providing a very long-running ecosystem. It means finding providing both a long-term ecosystem AND one in which behavior is plausible.

I find that some good parameters would have the fish to breed very quickly and that sharks should starve at a slower rate than fish breed but not too much so. Shark breeding should be around 3 times as slow as shark starvation. Of course, that's just one variation on the parameters and the shape of the environment (small, huge square, long-thin rectangle) can have a big effect as well.
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:iconsharkoftheday:
sharkoftheday Featured By Owner Nov 27, 2005  Hobbyist Writer
For the behavior to be plausible the breeding of fish would have to be adjusted with environment (breeding more when there are fewer of them and less when there are more of them) so that they don't fill up the screen. A steady ecosystem might be acheivable if there is a third factor of resources available allowing the fish to breed (or if the sharks did not eat every chance they got, which would not be necessary if they starved long after eating), although I'm not sure if available resources (plants to be precise) could help control the ecosystem or if they would simply complicate the system and make it even more unstable. For this it seems the most plausible behavior pattern is cyclical behavior, which is precisely what is acheived (besides that, in some ways it simulates seasonal fluctuations in the form of spikes and low points from which it rises).
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:icondovsherman:
DovSherman Featured By Owner Nov 27, 2005  Professional Digital Artist
The breeding of fish *is* adjusted with the environment because when there are lots of sharks, fish get eaten up and that means fewer fish to breed. Two many fish makes the sharks more likely to survive and breed until their are lots of sharks which eat up too many fish and sharks start starving until they drop down in numbers supportable by the remaining fish. Then the fish, having fewer predators and more room, start to increase in number again and the cycle continues.
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:iconclinkyinky:
ClinkyInky Featured By Owner Nov 26, 2005
Whoa.. I could sit here for hours and HOURS and never get bored. o.o'
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:icontoop:
Toop Featured By Owner Nov 26, 2005  Hobbyist General Artist
This is seriously cool. Its was great to watch the populations fluxuate in patterns. Patterns that grow so extreme that is results in the extinction of one species, in the case I watched, it was the sharks. Really cool simulation.
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:icondovsherman:
DovSherman Featured By Owner Nov 26, 2005  Professional Digital Artist
The way I have it, when the sharks go extinct, the simulation immediately stops. If the fish go extinct, it keeps going. Of course, if the fish go extinct, the sharks will soon follow since they'll have nothing to eat. But if the sharks all go extinct without killing off all the fish first, if the simulation didn't stop, the fish would simply grow and grow until the fill the world with no more room to move.
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:icontoop:
Toop Featured By Owner Nov 26, 2005  Hobbyist General Artist
Makes sense. Really well thought out, what was your inspiration to do a flash project like this?
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:icondovsherman:
DovSherman Featured By Owner Nov 26, 2005  Professional Digital Artist
I was just browsing a book on my shelf and thought it might be fun to try putting some of the experiments described into a Flash format. The book, "Armchair Universe" by A. K. Dewdney, is a collection of articles, many of which were previously published in the Computer Recreations section of Scientific American. There's a lot of nifty stuff in there like perceptrons, tesseracts, fractals, life, facebender, and so on. I'd also recommend Dewdney's "Magic Machine" and "The New Turing Omnibus" which have an even greater variety of interesting computer experiments.
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:iconpczelda:
pczelda Featured By Owner Nov 27, 2005   Digital Artist
Those books sound interesting. I have a few questions. 1) Does the "Armchair Universe" book include infinite regression? A common example, in case you're not sure, is place two mirrors parallel and facing each other, and if you look in either mirror, you can see reflected in it what looks like an unlimited number of mirrors. There was an article on that in S.A. a while ago, and had a neat infinite regression of the S.A. cover picture on the cover.

2) Is tesseract the same concept as how the characters in A Wrinkle in Time use to travel?

3) I've never heard of perceptrons, and I'm not sure what facebender is. Can you give me a quick description of each?

4) I've also been trying to find out about antimatter. I know it's the opposite of matter, but can you tell me if it actually exists, and if so, where (is it everywhere or not on Earth), and what might it look like?

I also have a question about the 4-D hypercube you uploaded. Isn't the fourth dimension time? How do you draw a shape that represents that?

Thanks, Dov(e), for your time, and you have some interesting posts this time around!
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:icondovsherman:
DovSherman Featured By Owner Nov 27, 2005  Professional Digital Artist
The three books by Dewdney that I mentioned all deal with mathematics and computer science, often with computer simulation, which is fitting since Dewdney himself is a mathematics/compsci university professor. I don't know if infinite regression would apply. It doesn't appear to be covered specifically although the concept of infinity is certainly raised a number of times.

I haven't read "Wrinkle in Time".

The idea of time as a fourth dimension has been around since the 1700s when Jean le Rond D'Alembert suggested thinking of time as a fourth dimension in an article published in the "Reasoned Encyclopedia or Dictionary of Sciences, Arts, and Crafts". Of course, in a Tesseract, we're treating the four dimensions as spatial dimensions so, while the mathematics may apply well to time as a fourth dimension, it's hard to conceptualize rotating through time since we humans don't really concieve our experience time in the same way that we experience space.

Keep in mind that just because I'm using four dimensions, that doesn't necessarily mean that one of them is time. Time is often called "the fourth dimension" in the sense that Newton's physics knew about three spatial dimensions and then was expanded to add the use of time as another dimension. In that sense, time is only "fourth" because we noticed it after the other three. But there is no real reason to assume that dimensions have to be listed in any particular order or that there are only four.

In mathematics, a dimension can be any value which can be varied. For example, you can consider colors on your computer screen to be 3-dimensional with the dimensions being redness, greenness, and blueness. Include the alpha channel and a computer image may be 4-dimensional. Add normal mapping and a texture used in 3D rendering may be 7-dimensional with 3 colors dimensions, one alpha dimension, and 3 more dimensions to define the surface normal.

A perceptron is a computer algorithm that can percieve. For example, optical character recognition (the way your computer scanner can turn a scanned image of text into a text file).

Facebender was a project using computer-simplified representations of human faces. One applications were to find the average human face and use the average to extrapolate charicatures of specific faces by exaggerating any differences from the average face.

Anitmatter is the time-reversed analogue of matter and such matter travels faster than light and can never slow down below the speed of light so it wouldn't look like anything since you can't possible see it. Some of antimatter theory is theoretical but there is fairly solid evidence for some of it, such as tachyons. I could be a little mixed up on this one though - I'm not well versed on antimatter.
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:iconpczelda:
pczelda Featured By Owner Nov 27, 2005   Digital Artist
Thank you for taking the time to respond and answer my questions.

I thought you might have read "A Wrinkle in Time." You really should, it's a great and really interesting book. Madeleine L'Engle is an amazing author; I've read several of her books, and have more that I haven't yet read. No matter, though. I can describe tesseract in the way the L'Engle uses it. Like I said before, that's how the characters can travel. Here's an example, it's also the example the book uses to describe it, so I guess L'Engle has copywright here: Think of an ant traveling on a string. One end of the string is point A and the other B. What tesseract does in this instance is "bend" the string so that points A and B are touching each other, and the ant can then travel directly from A to B. The book also described tesseract as the fifth dimension. What are your thoughts on this?
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:icondovsherman:
DovSherman Featured By Owner Nov 28, 2005  Professional Digital Artist
Well, a tesseract only have four dimensions, not five. I suppose it could be treated as a way to bend space but the only way such an A/B overlap would occur were if the fourth dimension were removed from the geometry, collapsing the tesseract back into a cube. Does the author describe the tesseract as being folded or distorted somehow?
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(1 Reply)
:iconsharkoftheday:
sharkoftheday Featured By Owner Nov 27, 2005  Hobbyist Writer
Slightly mixed up. Granted, I only know of anti-matter from school (my senior year high school teacher to be precise) and some independent study, but first there is a certain particle which can only travel faster than the speed of light and cannot slow down below the lightspeed barrier. This particle, like every other has its anti-matter particle. The theory is that matter came out of a vacuum which was the universe, as a result there was a hole in the universe and this hole is anti-matter. Anti-matter looks and acts exactly like actual matter (it has been seen and collected, but it is destroyed as soon as it comes into contact with a particle or matter), the only noted difference so far is that it usually has a reversed polarity (although this does not hold true for particles which are found with both or no polarity). I have heard there is a way to tell whether one is seeing matter or anti-matter, but I don't know what it is and I think this assumes that we are made of matter anyway when it is quite possible that we are composed of anti-matter (we are nothing more than holes in the universe). Also, once anti-matter is produced it can be held in place by strong magnetic forces (which i have heard of an experiment where a fairly large quantity of anti-particles were held in place and shot out in a beam at a group of matter within this controlled area, about the only thing that can be done with it).
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:icondovsherman:
DovSherman Featured By Owner Nov 27, 2005  Professional Digital Artist
I follow you but, if anti-matter isn't time-reversed (like tachyons which travel backward in time and experience temporally-reversed causality) what is it about anti-matter that earns it the prefix "anti"? Does it have negative mass and anti-gravity?

I was thinking that, if anti-matter were time-reversed, it would explain the annihilation effect without violating the "matter can be neither created nor destroyed" concept. When an electron and anti-electron meet, they annihilate each other, leaving nothing behind. But if the anti-electron is going backward in time, it would only seem to disappear from our viewpoint. From the anti-electron's viewpoint, it's just coming into being and may in fact simply be the electron reversing its direction in time. So what seems like two particles annihilating each other may actually be one particle changing time direction.
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(1 Reply)
:iconforlornlover:
ForlornLover Featured By Owner Nov 26, 2005
This is so simple, yet insanely entertaining.
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November 26, 2005
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