John Hogg (biologist)

John Hogg (1800–1869) was a British naturalist who wrote about amphibians, birds, plants, reptiles, and protists. In 1839 he became a member of the Royal Society.

John Hogg is credited with the creation of a fourth kingdom, accompanying Lapides, Plantae and Animalia, to classify Life. In 1860 he named the kingdom Regnum Primigenum or Protoctista. His rationale was simply that a kingdom of 'first beings' was necessary as these entities were believed to have existed prior to plants and animals.

In 1735, two living supergroups were formalized by Carl von Linné in his monumental Systema Naturae. All organisms were placed into the Kingdoms Plantae and Animalia. Linné added a third kingdom of the natural world in 1766; Lapides or ‘rocks’. These were deemed to be similar to plants in that they were, neither living nor ‘sentient’, i.e. not having ‘senses’. They were further characterised as solid bodied.

Hogg attempted to justify his arguments for a fourth kingdom with Spongilla, a freshwater green sponge, that was an animal known to exude oxygen in the light. However, the photosynthesis was later shown to be a result of symbiotic 'algae'.

Such an attempt to apply non-reductionist thought to classification systems during a period of biological debate made Hogg a protagonist within the field of nineteenth century biology along with Ernst Haeckel and Charles Darwin.