Nutrition is the balance between nutrient intake and the needs of the body. Almost all animals eat other organisms dead or alive, piecemeal or whole: unlike plants, animals cannot photosynthesise. They must consume food for both energy and the organic molecules used to assemble new molecules, cells, and tissues. Diversity in diets: herbivores dine mainly on plants/algae, carnivores mostly eat other animals, omnivores (omni latin for all) do not in fact eat everything, but they do regularly consume animals as well as plants/algae. Keep i(cid:374) (cid:373)i(cid:374)d: (cid:373)ost a(cid:374)i(cid:373)als are opportu(cid:374)isti(cid:272) feeders, (cid:373)ea(cid:374)i(cid:374)g they"ll eat foods outside their standard diet when their usual foods (niche) is unavailable. 6. 1 a(cid:374) a(cid:374)i(cid:373)al"s diet (cid:373)ust supply (cid:272)he(cid:373)i(cid:272)al e(cid:374)ergy, orga(cid:374)i(cid:272) (cid:373)ole(cid:272)ules, a(cid:374)d esse(cid:374)tial (cid:374)utrie(cid:374)ts. An adequate diet must satisfy 2 nutritional needs: chemical energy for cellular processes, building blocks for macromolecules, essential nutrients. Essential nutrients are materials that an animals cells require, but cannot synthesize.