Level 1: primary producer(plants and other organisms that primarily acquire energy from natural forces(geothermal in deep ocean ecosystem, solar energy on earth surface))
Level 2 herbivores, consume level 1 organisms as the main source of energy
Level 3 carnivores that eat level 2 organism as the primary source of energy
Level 4 and 5(if the base of the food web is large enough) Apex carnivores who consume mostly level 3 and sometimes level 2 organisms for food.
From level 1 to level 4, 5, each level has 1/10 number of organisms than the lower level because only 1/10 of whatever they eat convert to their body mass, so there need to be 10 times more prey than predator for the higher level to not starve to death and for the food web to be sustainable.
