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Calling All Sea Monkey Experts/Lab Test Help

PostPosted: Wed Sep 24, 2008 4:36 pm
by USSRGirl
I'm scrounging ideas for how to measure the hatch rate and reproductive rate of brine shrimp in a bio experiment I'm doing. Besides the obvious don't-be-so-lazy-and-count-them (for reproductive rate I'm counting the number of females with egg sacks and also the initial population count minus the end population count), any more "impressive" ideas out there? I've searched around but haven't come up with much.

PostPosted: Wed Sep 24, 2008 4:55 pm
by EricTheFred
The only thing that comes to mind immediately is some method of tracking CO2 output of the population... but I don't have a clever equipment setup in mind, just that first glimmer of an idea.

PostPosted: Wed Sep 24, 2008 5:13 pm
by USSRGirl
Hrmm... that's a good idea. I'll google around and see if tracking the carbon dioxide would work for this experiment. If nothing else, I might be able to add CO2 levels into my data along with numerical counts. My lab is a little sparse equipment wise, but I'll be reinbursed for anything up to about 50 bucks, so [relatively cheap] equipment ideas are welcome.

PostPosted: Wed Sep 24, 2008 5:52 pm
by Kaligraphic
For numbers that can reasonably be counted, rather than extrapolated, it's definitely better to actually count. Indirect measures should only be used when direct measures are impractical or impossible, as they are less reliable than direct measures.

In short, I suggest getting off your backside and just counting them.

Also, Opera > Seamonkey

PostPosted: Wed Sep 24, 2008 6:44 pm
by Dante
I suggest counting the following... take a small segment of your tank, (Just a general random one, not one particularly lacking them or having an over-abundance) and count the amount of seamonkeys in that square area... then measure the length and width of that segment and the depth of your tank... this is the number of sea monkeys present within that volume of tank...

MATH FINALLY COMES TO THE RESCUE!!!

Because the sea-monkey population will be evenly spread throughout the tank (I don't know how big they are but I figure they're pretty small) you can then measure the width, depth and height of the tank area filled with water. Now... Just use the following formula:

Total_Volume * (Sea_Monkeys_In_Small_Volume / Small_Volume)

This should give you an approximate number of sea monkeys for the entire tank by only counting a small number every time... In fact you can change the size of your distance measurements and count even less sea monkeys as their numbers get large... You sea monkey population as a function of time should resemble something called the Logistic curve.... that means that it should rise rapidly like an exponential (e^x) and then fall off as the population runs out of food leveling off at the end... I did this with zombie population growth... it was fun!!!

(Ironically if you have a predator prey system with something to eat Sea Monkeys, a sine wave looking thing results O_O, that's why enviroments look the same year after year... their populations are simply waving back and forth, you can actually describe these results using differential equations pretty cool (boring) right :P. )

PostPosted: Wed Sep 24, 2008 7:01 pm
by Kaligraphic
Of course, that does fail if they aren't evenly distributed in the tank, and is better and more accurately posed as "use a smaller tank".

PostPosted: Wed Sep 24, 2008 7:57 pm
by USSRGirl
Kaligraphic (post: 1260778) wrote:Of course, that does fail if they aren't evenly distributed in the tank, and is better and more accurately posed as "use a smaller tank".


My thoughts exactly. XD The tank is not going to be any where near big enough for that to work, Pascal. I intentionally got a small tank for counting purposes. Sea monkeys don't exactly explode in growth rate and like Kal said that leaves a pretty wide error margin since from what I've seen of them they don't congregate to certain areas (I'll end up counting the majority or the minority of monkeys in the first equation alone). They're easy to count, but I was just wondering if there was something that I could add to make it more... I dunno... measurable? Rather than just "I counted such-and-such amount of births... ect." On the other hand, if counting works, counting works. I don't want to throw a whole slew of meaningless numbers and figures at my TA just 'cause I can.

PostPosted: Wed Sep 24, 2008 8:55 pm
by Peanut
Counting doesn't just work, I'm pretty sure (like 99.9%) it's usually what Biologist do out in the field when they are doing the exact same studies. So in other words...count...I don't think there is any other way to accurately measure reproduction rate and hatch rate especially with Sea Monkies...

PostPosted: Thu Sep 25, 2008 10:15 am
by USSRGirl
Hmm. True. Thanks for the input guys (it was much appreciated). I think I will just go with straight counting. Now I just need to find names for them... hrmm... Stalin, Lenin, Marx, Trotsky, Mao, Castro, Putin...

PostPosted: Thu Sep 25, 2008 2:26 pm
by Kaligraphic
One should be named Leroy.

PostPosted: Thu Sep 25, 2008 5:35 pm
by Peanut
Kaligraphic (post: 1260905) wrote:One should be named Leroy.


...and another Jenkins...

PostPosted: Thu Sep 25, 2008 5:54 pm
by USSRGirl
Behold the mystery of the crustacean monkey water! It's a miracle my brothers and sisters, a miracle! *coughcough*CanIhasmoneyandAnow?*coughcough*

PostPosted: Thu Sep 25, 2008 6:32 pm
by Peanut
USSRGirl (post: 1260929) wrote:Behold the mystery of the crustacean monkey water! It's a miracle my brothers and sisters, a miracle! *coughcough*CanIhasmoneyandAnow?*coughcough*


No, but you can get a Gold Star and a sticker that says "You did great" on your paper...too bad neither of them count as an A...