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Many dogs will get snippy with a toddler, even if they have not been so before.
I would see the vet if I were you to rule out a medical reason for the behavior. Since it was the ear that she pulled, I would be concerned that she has an ear infection that might be causing problems.
As dogs age, they often cannot tolerate small children. To ensure your baby's safety, be sure that you don't leave them alone together and closely supervise them even when you are there. You may want to use baby gates to keep them apart.
So - first, see the vet to rule out a medical cause.
Let me know if you still have questions.
She could have been. Since she is suddenly aggressive to other dogs AND to your toddler, you need to see the vet for an exam. She might even be experiencing some arthritic changes that are making her uncomfortable. This is common as the dog ages. If this is the case, the vet can prescribe an anti-inflammatory that will help a great deal.
I hope this helps more!
Let me know if you still have specific questions.