The Origin Of The Dinosaurs

In a discussion on global warming and the influence of men of any on the process I came across this question:

I learned in science class that dinosaurs we related to reptiles, but now I learn that they are related to birds

Well the answer is that there is no contradiction if we think about the evolutionary line.

Dinosaurs came are part of the archosaurs, a group that includes crocodiles and birds. Surprising Ha? The same zoological family includes dinosaurs, crocodiles and birds.

People studying dinosaurs believe that they live even today as birds and this conclusion was based on the feathers on their skeletons.

Species can evolve from a specific zoological family and then evolve into a new thing all together.

Here is a good explanation of the dinosaurs - birds question

The notion of a “missing link” is an out-of-date misconception about how evolution works. Archaeopteryx (and other feathered fossils) shows how a branch of reptiles gradually acquired both the unique anatomy and flying adaptations found in all modern birds. It is a transitional fossil in that it shows both reptile ancestry and bird specializations. Wells’s claim that “supposed ancestors” are younger than Archaeopteryx is false. These fossils are not ancestors but relatives of Archaeopteryx and, as everyone knows, your uncle can be younger than you!