Science Buddies: "Ask an Expert"

Hi, I have seen an article about artificial selection by choosing guppies that have relatively big brains. Scientists chose guppies with big brains and made guppies with more big brains by breeding them. Then, how can I vary them by brain sizes? I thought about dissecting it, but after anatomy, it will be unable to breed them because it's dead. I wonder there is a certain way to know how big it is.

Are they trying to breed smarter guppies by selecting for those with larger brains? Did the article say how they knew which guppies had bigger brains? Maybe their heads are larger, although on a fish i'm not real sure where you would measure the 'head'. Maybe you could do it the other way around and selectively breed them based on intelligence, then see if the smarter ones have bigger brains.

I don't think brain size corresponds to intelligence, however. Einstein's brain was said to be smaller than average (link no longer available / www.aip.org/history/einstein/einbrain.htm). I think it is not the size that matters so much as how it is wired. Octopi have amazingly complex brains for an invertebrate and are much more intelligent than fish (http://scienceblogs.com/pharyngula/2006 ... us-brains/)

I don't know what you planned to do with this project, but I think setting up a test to measure guppie intelligence and then breeding the smartest ones might be more productive than trying to guess what their brain size is. In nature, it isn't necessarily the smartest fish that survive to breed, but you can set up artificial conditions where you can choose the ones to mate based on better ability to perform some fishy task. Then you could see if their children or grandchildren could learn the task quicker than nonselected guppies.

Let us know what you have in mind and we will try to steer you into a good project.

Sybee

Hello there,

SciB gave you some great advice already, and I think this is quite an interesting topic. I'm pretty intrigued as to how the scientists knew which guppy had large brains or small brains without having to dissect them out. I think that SciB offered a great alternative to brain size--that is, to look for fish that perform well at a certain task, breed those fish, and then see if their offspring are better at performing that task than offspring from parents that weren't great at this task. Another idea would be for you to grow some guppies in a certain condition for some period of time, and then afterwards, mate those guppies and test whether their offspring would acclimate to that same environmental condition better than guppies that haven't been exposed to that certain condition before.

Let us know your interests and what questions you would like to answer, and we'd be glad to help you brainstorm more ideas!

Best,
Connie