Genesis 1
29 "Then God said, 'I give you every seed-bearing plant on the face of the whole earth and every tree that has fruit with seed in it. They will be yours for food. 30 And to all the beasts of the earth and all the birds in the sky and all the creatures that move along the ground—everything that has the breath of life in it—I give every green plant for food.' And it was so. 31 God saw all that he had made, and it was very good. And there was evening, and there was morning—the sixth day." NIV
(Jgl comment-this was before the Fall of course. Most if not all biological life forms, presently, have been shown to have the ability to eat botanical substances for nutrition-even if they tend to be carnivorous. See book for sale in the store on this website that discusses this more: The Beauty of God's Creation in the midst of corruption.)