Feeding

Bastard snakeMalpolon monspessulanusfeeding on an Iberian lizard (Podarcis hispanica).

The feeding is the ingestion of food by organisms to provide themselves with their nutritional needs, fundamentally to obtain energy and develop.

In humans, the diet of each person varies according to numerous factors: tastes, age, physical activity, economic means or availability of products in the region in which they live. Culture also influences food, since, for similar products, different customs and traditions exist in each place.^{[citation required]}

Biological approach

Animals and other heterotrophs must eat in order to survive, such as carnivores, which eat other animals, herbivores, which eat plants, omnivores, which eat both plants and animals, or detritivores, which feed on detritus. Fungi carry out external digestion of their food, secreting enzymes, which then absorb the dissolved molecules resulting from digestion, unlike animals, which carry out internal digestion.

The chemical reactions necessary for life depend on the supply of nutrients. In higher organisms these nutrients are synthesized by photosynthesis (plants), or made from organic compounds (animals and mushrooms). There are other energy sources for microorganisms: for example, some archaea obtain their energy by producing methane or by oxidation of hydrogen sulfide or sulfur.

Vegetable nutrition

Plants are mostly autotrophic organisms. They are capable of synthesizing organic compounds from mineral salts and from solar energy through the chlorophyll function or photosynthesis.

Animal feed

Animals are heterotrophic organisms, they depend on one or more different species for their nutrition. Food is transformed into nutrients through digestion. The diet, whether carnivorous or herbivorous, has a great influence on animal behavior, and determines its status as predator or prey in the trophic chain. They can have an omnivorous or more specific feeding behavior, such as folivore, piscivore, scavenger, nectarivore, saprophagous, etc. Like other animals, man depends on his environment to ensure his basic food needs.