The nutrition influences growth and reproduction of animals. In addition to elemental nutrients, such as phosphorus and nitrogen, animals depend on an adequate supply of essential biochemical nutrients, such as polyunsaturated fatty acids (PUFA), sterols, and certain amino acids. The availability of these essential biochemicals is highly dependent on the abundance and species diversity of primary producers and the efficiency of transfer to higher trophic levels. Nutrient deficiencies can have a significant impact on the growth and reproduction of an individual, thus affecting the dynamics of populations and the transfer of substances and energy in the food web.