Interesting Experiment

[ShellsandScales]

Got a little experiment I was going to keep to myself but I'm just way to interested to see what some of the experts on here think. So I was watching a special, and I knew this fact before hand, but invertebrates in the fossil record used to be much larger than they are today. That is attributed to the higher oxygen levels that used to be in the atmosphere. Allowing inverts to metabolize more efficiently and experience optimal growth. So that got me to thinking. I know botanists and growers use co2 to increase growth and yield of their plants. I wanted to set up some T's and keep some at regular atmospheric conditions and some in enclosures with elevated oxygen levels. In theory, the T's with more oxygen can metabolize better and have more optimal growth, growing larger. Now many other questions arise. When you remove these super T's from the oxygen rich environment is there enough oxygen in the regular atmosphere for them to function normally? They have such low oxygen requirements that I think they can. Is elevated oxygen just going to optimize growth or is it necissary for adults to metabolize well enough to survive. Also makes me try to wrap my brain around... HAS, over time, the decrease in atmospheric oxygen affected the genes of inverts or do they still retain in their genes the ability to grow much larger?

Hope this gets the wheels spinning. If anyone wants to actually set up this experiment please PM me I would really like to collaborate on this. Otherwise just let me know what you think. I hope I illustrated my point and theory clearly. PM me if you have any direct questions or just tack onto this thread with comments and observations. Thanks.

 

[gvfarns]

Invertebrates from the fossil record genetically adjusted to the higher levels of oxygen through natural selection. The size of an animal is written in the blueprints of its genes and can't be affected significantly using food, hormones, or anything else, although its time to maturity definitely can be affected. Well, its growth can be stunted, but for example you can't exceed the height that your body was designed for using food, hormones, supplements, extra oxygen, etc. My understanding of the plant experiments is that they grew faster in the presence of more CO2, not bigger. Under optimal circumstances (that is, the seasons not changing on them and stuff) I don't see why one plant would grow taller than the other in the a richer CO2 environment. I might be wrong about that, though. Not a botanist (or biologist).

Another note about fossil invertebrates is that many of them that were though to have been bugs like ours it turns out were water dwelling animals that happen to look similar to living land dwelling bugs.

There are two limiting factors to invertebrate physiology that i know of. One is the capture and transportation of oxygen. The other is that as animals increase in size they weigh more at a cubically increasing rate, and the exoskeleton design doesn't scale that well. (that is, exoskeleton strength scales at a squared rate, so for large animals, the exoskeleton can't hold them well unless it becomes unreasonably thick).

Anyway it's possible that higher oxygen will speed growth, just as more food and warmer temps does. I'd be interested to see your results if you do this. However, I think just like more food and warmer temps, I would not expect oxygen to affect the final size of your T's.

 

[gvfarns]

Actually no one has run an experiment to see whether powerfeeding or higher temps changes the adult size of the T. I'd be interested to know that results of that, and it's an easier (cheaper) experiment to run. All we know now is that is speeds up growth. For all we know, powerfeeding and high temps may reduce the final size of T's.

 

[bliss]

here are some thread that may help

http://www.arachnoboards.com/ab/showthread.php?t=95224&highlight=prehistoric+tarantulas

http://www.arachnoboards.com/ab/showthread.php?t=128441&highlight=prehistoric+tarantulas

http://www.arachnoboards.com/ab/showthread.php?t=116811&highlight=prehistoric+tarantulas

--dan--

 

[ShellsandScales]

Yeah the specific show I was watching was with jeff corwin and they had very large tarantuls that were found from the more receint fossil record. They were massive over 2 feet. So they did weigh a lot but could still support their body weight.

I do suppose that they are naturally selected. However they have proven that you still can retain the traits of your ancestry in your dna it just needs the right hormone or chemical to be produced or present at the right time in developement to "reactivate" the old dna code. They have been able to make chicken embryos grow teeth and scales that are coming from their reptillian ancestry. That dna code is not lost to natural selection, it has just been activated in a different way or at different times. There are really only a handful of genes that controll the development of the body in all animals including growth limit and rate and all animals are really much more closely related than previously thought. I'm no biologist but that is my understanding of it.

Hypothetically you can take a strand of dna and based on how and when you enact the "programs" encoded in the DNA you can build any animal that has ever existed and design new ones that haven't. They have proven this in it infancy by giving chickens feathers on their legs and making fruit flies grow antenna where their eyes or legs should be. It is really very easy to manipulate genes to produce the animal you want they are just refining the science of it and it's only a matter of time before they have mapped out all of the genes of known animals and then you have a blueprint. A little bit off of original topic but it makes me think that you can affect the final size of an animal.

 

[gvfarns]

Well that could be cool. Can't hurt (very much) to try it.

Make us a two pound blondi!

 

[ShellsandScales]

I think if the experiment was to be done you would want to try with a species that is much shorter lived and smaller ex. C. elegans.

 

[barabootom]

I read, I don't remember where, that the tropical rainforests are changing becuase of elevated CO2. The faster growing trees are getting taller and growing so fast they are shading or overcrowding the slower growing trees, thus decreasing the variety that has traditionally existed in our times. My understanding is that CO2 does affect the the growth rate, production of fruit and size of a plant. The growing season also does. Many of the giant vegetable records come from Alaska, because they have such long days. Increased oxygen levels may play some part in size and growth rate but other factors probably did too. Maybe gravity was less, we really can't be sure. I've seen 8+ inch imperator scorps in old insect collections, but who sees them in the pet trade? I think all the giant ones were collected and the genes removed from the gene pool. It's a worthy experiment and should be done but I wouldn't expect dramatic results. I agree a fast growing specie should be used so several generations can be observed. If optimum conditions exist for a long period of time I think the chance for measurable consistent size increase is more likely. Good luck. If I can help I will.

 

[barabootom]

Another thing to consider is those two foot tarantulas in the fossil record probably had a very long time to develop and were eating 1 foot grasshoppers.

 

[blazetown]

Another thing to consider is those two foot tarantulas in the fossil record probably had a very long time to develop and were eating 1 foot grasshoppers.

agreed...and they were slightly less complex organisms....hard to say tho. Alot of things could happen like maybe you OD your Ts on oxygen. I would say try it if you have the money. I would keep the temperature higher aswell like 92F.

 

[ShellsandScales]

These are great ideas. Ideally there would be several different setups under different conditions with a control group as well. so you can see what factors have an effect.

 

[Le Wasp]

I've heard the oxygen theory and I don't believe it one bit. Today's insects use spiracles to deliver oxygen straight into individual muscle cells. -and here's the kicker: their spiracles are closed more than 90% of the time. If they wanted more oxygen, they could easily get more - they're definitely not limited by the stuff. I'm not too sure about spiders and book lungs, so they might do better with more oxygen.

The reason they're closing their spiracles so much is because there is too much oxygen. Apparently oxygen has a lot of free radicals that damage tissues, so the insects are limiting the amount of oxygen that gets delivered to their muscles.

Anyway, my theory about why all the arthropods got smaller is related to birds. Birds love to eat arthropods and they're good at it. If a bug takes 5 years to get really big and reproduce, just to get eaten by a bird, it's wasted 5 years and it wouldn't have any offspring. Plus, bigger bugs are better meals for birds, so they'd be eaten up in a hurry. Smaller bugs are better at hiding and take hardly any time to reach maturity.

 

[gbbgirl]

Would you call this type of bird a goliath birdeater bird? or a blondi eater bird?

Ummm...crunch tarantulas.

 

[ShellsandScales]

Yeah I was more interested in T's than all inverts. Book lungs work by diffusion so it is directly related to the amount of oxygen in the atmosphere and it is fact there is much less oxygen today than in the past. I'm not following along with the bird predation theory, at least for T's it may be a factor for other invertebrates. T's don't typically put themselves in a position to be preyed upon by birds. I'm sure it happens but for it to be enough frequency to have a major evolutionary impact is questionable. Great observation though. I think predation may have had an effect on prey species of inverts but less likely for predatory inverts.

 

[WyvernsLair]

a 2 foot OBT...scary

 

[Drachenjager]

Yeah the specific show I was watching was with jeff corwin and they had very large tarantuls that were found from the more receint fossil record. They were massive over 2 feet. So they did weigh a lot but could still support their body weight.

I do suppose that they are naturally selected. However they have proven that you still can retain the traits of your ancestry in your dna it just needs the right hormone or chemical to be produced or present at the right time in developement to "reactivate" the old dna code. They have been able to make chicken embryos grow teeth and scales that are coming from their reptillian ancestry. That dna code is not lost to natural selection, it has just been activated in a different way or at different times. There are really only a handful of genes that controll the development of the body in all animals including growth limit and rate and all animals are really much more closely related than previously thought. I'm no biologist but that is my understanding of it.

Hypothetically you can take a strand of dna and based on how and when you enact the "programs" encoded in the DNA you can build any animal that has ever existed and design new ones that haven't. They have proven this in it infancy by giving chickens feathers on their legs and making fruit flies grow antenna where their eyes or legs should be. It is really very easy to manipulate genes to produce the animal you want they are just refining the science of it and it's only a matter of time before they have mapped out all of the genes of known animals and then you have a blueprint. A little bit off of original topic but it makes me think that you can affect the final size of an animal.

its a bloody crab not a spider.... they originally had that thought to have been a spider but now know better. It was called megarachnae and when they figgured it out called it mesothelae , which does exist but its not that big lol
problem is they think we are too stupid to know better or keep up.

 

[Drachenjager]

THERE WERE NO 2' SPIDERS !!!! megarachnae(mesothelae in later incarnations of the shows) is BS. it was a water scorpion/crab like thing.
period. They even know its BS but wont delete it from these shows. one reason i think Corwin's a buffoon