section_path: Scientific classifications/Egg size and yolk
section_name: Egg size and yolk
paragraph_text: Egg size and yolk
  
  Vertebrate eggs can be classified by the relative amount of yolk. Simple eggs with little yolk are called microlecithal, medium-sized eggs with some yolk are called mesolecithal, and large eggs with a large concentrated yolk are called macrolecithal. This classification of eggs is based on the eggs of chordates, though the basic principle extends to the whole animal kingdom.