Not sure I understand the sentence, but few things could be said already:
sententia facit necesse esse mundo ... quaesitum esse: Not sure it works grammatically. It is certainly not the best idiomatic choice to have mundo in the dative and the adj in accusative/nominative. It is preferred, I believe, to use other formulae with necesse est (there are other options not with dative). Also I am not a fan of facit necesse esse... here. Consider using simple verbs like cogit (i.e., cogit mundum ...) that spare the usage of necesse est. Or other perhaps easier to follow with ut something like efficit ut ... (c.f., efficis [, Venus,] ut cupide generatim saecla propagent). Another approach is to use the gerundive to express the obligation: facit/reddit mundum quaerendum
ad reperiendum multae feras bestiae. First, feras should be ferae or rather mulas bestias. Second, according to A&G "The gerund with a direct object is practically limited to the genitive and the ablative" so perhaps it should be ad reperiendas multas feras bestias.
quas ... ac ostendendas. It looks like something is missing in this clause which is a verb.