Question

There are many more –er and –ir verbs than –ar verbs

Answer 1

Yes because ar verbs are mostly action words

Answer 2

Yes, there is.

"ir" verbs usually indicates on movement (going somewhere). This verb can usually also stand alone and can act a singular word.

example: "Ma', puedo ir a la playa con mis amigos este sabado?"

The girl is asking her mom if she can go to the beach with her friends on Saturday.

"er" usually indicates  present-tense. It cannot stand alone as a singular word the way "ir" can.

example: Saber (to know)

Finally "ar" is a less used verb in spanish. It also cannot stand alone as a word. "ar" and "er" are very simaler verbs, since they both indicate to do something.

Example: Nadar (to swim)

I hope this helps.