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I am currently working on a science project for a county competition. I was wondering if you could either direct me to someone who could help me in the subject that I am working on or provide some information that could help me if you had the time.

I was developing the idea of testing what variables change reproduction rates in bacteria or mice. In this experiment a control would be normal conditions and the rate of growth in these conditions. By limiting food or developing competition / a destructive event, you can measure how these variables can effect reproduction. What seems most interesting in this experiment, though, is what might happen if it would be applied to mice. It can be tested whether or not mice would still reproduce if there was lack of food creating an environment that cannot support more than the number of mice already present.

Question Date: 2003-03-13
Answer 1:

Based on animal rights/care considerations, I would strongly suggest sticking with bacteria or yeast. They are easy and cheap to take care of and your experiments will be MUCH shorter (they reproduce in the span of hours, where mice take weeks). If you really want to move to a more "advanced" model organism, you could try worms (you could try to contact people in Joel Rothman'a lab at UCSB) or fruit flies (Steve Poole at UCSB). These organisms have a more direct link to mammals, yet are still easy to work with.

There are very stringent guidelines that have to be followed to do experiments on mice - and "starving" them might not be considered humane. I think it is lot of trouble where you could get interesting results in the other model systems I mentioned.

Answer 2:

I think that your line of thought regarding experimental questions is good. I do have some suggestions based on what the limitations of your project are. First, you should probably consider doing this experiment in bacteria over mice. They are easy to grow and they reproduce asexually by fission (cell division). You can easily monitor different populations with a device called a spectrophotometer. If you do not have a spectrophotometer you could probably also grow them on plates of agar (bacteria food) and ask about reproduction based on how many colonies (spots of bacteria) you see on the plate and how big they are. It is very easy to add things to agar or take things away depending on what your experiment is testing.

The other concern you mice for experiments in general. Because they are vertebrates and have very specific government regulations. Most of the time you can not do experiments like this without consent to ensure the animals are not being treated improperly. Also, it is hard to measure reproduction in an animal that relies on behavior to reproduce and only reproduces every couple of months. I hope this has helped you. Go with the bacteria, you can ask all kinds of interesting questions!!

Answer 3:

From an ecological standpoint, this is an interesting question: do animals reproduce less when conditions are bad? Normally I encourage people to test their own hypotheses, but in this case, I'm going to suggest that you look at the mouse studies in the literature. That's because scientists do their best to limit stress and suffering of animals. Almost all animal scientists (including me) belong to organizations with very strict guidelines about how vertebrate animals can be treated in research. Earlier studies have shown that stress (even crowding with plenty of food) decreases reproduction rate in mice.

Invertebrates, plants, and bacteria are not covered by any welfare guidelines as far as I know, so you could ask the same question with them. Ethical issues aside, you will get a faster answer with most of these organisms. One good species to use for a study like this would be the Wisconsin fast plant. It's small plant that goes from seed to seed in about 40 days.

You can find out more about them at
fast plants .

Then you can set up different "stress" situations manipulating things like crowding, light, etc.

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