Answer
No, you did not create a new life form, as it was likely a spore from the air landed in the solution and germinated. This would result in the "life forms" observed. If one wanted to modify this experiment, one could use a swans neck flask.
Work Step by Step
The scientist is correct that the solution needs to be open to oxygen for anything to grow, however, having it completely uncovered to the elements can result in anything getting into the solution and tainting it, such as a spore from the air. This is more than likely what happened to the solution, that spore blew into the solution from the air and germinated. This would result in the new life forms. However, if one wanted to avoid this, they would have to use Louis Pasteur's swans neck flask. The unique curvature of the neck would not allow for any spore to simply be blown in by the air, while still allowing for the solution being contained to be open to oxygen.
