She is taken by surprise when she later realizes that Tom is back with Ashley. Tom defends her to his mother.

What does 'is taken by surprise' mean?

What does 'defends her to someone' mean?

When something surprises me, I am taken by surprise. There's not much difference between "She was taken by surprise when..." and "She was surprised that..."

If one person, Person A, says bad things about me, and someone else, Person B, argues back and says that it's not true or not accurate, Person B has defended me to Person A.
Thank you very much for your great explanation, GG. I get it !