Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 31

Sanskrit:

पाषण्डपथवैषम्यं प्रतिलोमनिवेशनम् ।जीवस्य गतयो याश्च यावतीर्गुणकर्मजा: ॥ ३१ ॥

ITRANS:

pāṣaṇḍa-patha-vaiṣamyaṁpratiloma-niveśanamjīvasya gatayo yāś cayāvatīr guṇa-karmajāḥ

Translation:

Please also describe the imperfections and contradictions of the faithless atheists, the situation of crossbreeding, and the movements of the living entities in various species of life according to their particular modes of nature and work.

Purport:

The combination of living entities in different modes of material nature is called crossbreeding. The faithless atheists do not believe in the existence of God, and thus their paths of philosophy are contradictory. Atheistic philosophies never agree with one another. Different species of life are evidence of varieties of mixtures of the modes of material nature.