Science Buddies: "Ask an Expert"

My aspiring scientist has already conceptualized his science fair project for this year, even though they will not be required to begin until second semester.

He and I had been discussing prehistoric insects, and the fact that during certain periods, they were considerably larger than they are today. After a lengthy discussion of insect breathing anatomy, I explained that the current theory is that they were able to grow larger because the oxygen content in the atmosphere was higher at the time.

His response was a question as to whether today's insects would grow larger in a high oxygen atmosphere - and a science fair project was born...

I have done a bit of internet research on this, and have found that this experiment has been done at some universities to varying extents, but he doesn't really need to know that - after all, he did come up with the idea on his own...

On that note, if anyone knows of specific insects that respond well to high oxygen levels, please advise. The most successful experiment that I discovered online used Dragonflies, but they are notoriously difficult to raise. I was wondering if butterflies might be appropriate? they are easy to raise, easy to get, and would be easy to measure. I hadn't seen any O2 experiments with them, but I'd prefer to get him set up with something with a decent chance of positive results.

Incidentally, FYI, most insects were unaffected or actually had retarded growth - beetles for example

Mostly, I am looking for any advice on a setup. We have decided to build two terrariums - one for a control and one for the hyperoxic (correct term?) experiment.

I'm struggling with the method to maintain a specific oxygen level in the experiment. I assume we need an oxygen sensor - which I have located at Carolina Biological, but maintaining it over time seems like it will be a hurdle. Is there some setup that will regulate the level to keep it constant?

Thanks for any advice you can give

Hi ppacific407!

That's such an interesting idea! It's great to hear that your son came up with a defined and thought-out experiment at the outset.

In biology, the fruit fly (Drosophila melanogaster) is commonly used as a model organism, since it is easy to maintain/grow and yields results quickly, among other advantages. You may want to consider Drosophila--I presume it would be fairly easy to obtain, if you had access to a provider like Carolina Biological, as you mentioned. In addition, another idea could be to use an insect like a millipede or cockroach (very easy to measure size, and they don't fly around).

I did a simple Google search, and here is a little background info from a university study that could help you: http://researchmatters.asu.edu/stories/ ... xygen-2593.

The control/experimental setup sounds perfect. I'd suggest maintaining the experimental terrarium at a consistently high oxygen level with an oxygen pump and mini-tank setup that regularly introduces only a set volume of O2 into the terrarium constantly. (It just came to mind actually, that another option, if it's too difficult to introduce extra oxygen, could be to test oxygen deficiency instead and see if growth is retarded or slowed.)

If other Experts could chime in as well, that would be great!

I hope this helps!

Best,
scibuddyAK

Hi ppacific407!

That is a very original idea, great job! Expert scibuddyAK mention some really good points about the the fruit fly being used commonly as a model organism and the oxygen pump.

Adding on to was was said, another organism in biology is a small freshwater crustacean, called Daphnia(AKA water fleas) which could be used in experimentation. However, because this is a very microscopic organism it would be very hard to measure the growth, you can count its heartbeat by looking at the organism through a microscope after it is placed in the two different environments.

You would have to keep the daphnia in freshwater...So you could create artificial habitats, one with an extra oxygen source (such as underwater plants that gives out high levels of oxygen... or even the oxygen tank mention by scibuddyAK) and another without the oxygen source. You can measure the amount of oxygen in the habitat with the oxygen sensor. After storing them in the habitat for a give period of time, you can measure the heart rates of the daphnia and compare them.

Here is a simple heart rate lab done in many high school biology classes, you can use to learn more about how to measure the heart rate of the Daphnia: http://www.biologycorner.com/worksheets ... trate.html

Also here is another website that gives a lot of information about daphnia and other variables you must pay attention to so you results will be as accurate as possible: http://web.cecs.pdx.edu/~davidr/discus/ ... phnia.html

If using this organism in your experiment then you must make sure that you control the pH, ammonia levels, temperature, etc. otherwise your experimentation will not provide the most accurate results.

I hoped that helped. Good luck on your science project!

nikhita8