In some Islamic schools even Darwin‟s theory of man‟s evolution from monkeys is being taught.

Answer

Most assuredly it is among the worst acts of kufr. The teacher who teaches such rubbish kufr loses his/her Imaan, and the baaligh students also become kuffaar. It is indeed lamentable and shocking that such kufr is being taught in schools dubbed 'islamic'. Parents are 100% liable for the kufr acquired by their children attending these schools of Iblees.