You can easily see vertebrae for yourself if you buy a whole trout (with the bones in) at the grocery store and cook it. If the grocery store doesn't have any with the bones in, ask the fish man and he will probably get you one. Then just put the fish on a cookie sheet and stick it in the oven on broil for about ten or fifteen minutes.
Put the fish on your plate (you can cut off the head first if you want) and carefully slice the top flesh away from the bones. You will see the vertebrae all lying in a row. When you have eaten the top half, carefully lift off the skeleton, and then you'll be able to eat the bottom half.
Making chicken soup
After you're done eating, boil the bones for an hour or two to get all the flesh off them, and you'll be able to separate the vertebrae and see what one looks like by itself. They make interesting beads, if you want to make them into a necklace, afterwards.
If you want to compare fish vertebrae to chicken vertebrae, just buy a whole chicken and boil it for soup. After an hour or so, take out the chicken and pull off all the meat (let it cool first!), and you'll be able to check out the vertebrae. (Hint: if you've cooked the chicken the usual way, then the vertebrae will be on the bottom). If you put in celery, carrots, and onion when you start, you'll have a great chicken soup when you're done, too.