The Minnesota Senate approved and sent to Gov. Mark Dayton a bill that ends seniority-based layoffs for teachers, a bill that is strongly favored by business groups and bitterly opposed by the teachers' union.

Dayton has said he opposes the bill and will likely veto it.

Following approval by the House earlier in the week, the Senate voted 35-28 Saturday evening to pass the bill.

The issue is known as "last-in, first-out," or LIFO. Supporters of the change say when layoffs occur, evaluations of teachers should play a role, and the decision should not be based purely on the number of years a teacher has been employed. They argue that the current system punishes young, enthusiastic teachers and hurts students.

Some opponents have agreed that the system needs to be changed, but they say that the necessary teachers' evaluation system hasn't yet been developed. Others say the Republican-backed bill is an attempt to undermine the influence of the teachers' union, rather than an attempt to help teachers.

Dayton has cited both of these complaints in opposing the bill.