Carl Linnaeus developed two Kingdom system of classification which include kingdoms Plantae and Animalia. The kingdom Plantae includes all plants and all animals were included in the kingdom Animalia. The two Kingdom system of classification was used till recently. This system did not differentiates between the eukaryotes and prokaryotes, unicellular and multicellular organisms and photosynthetic such as green algae and non-photosynthetic such as fungi. Therefore, the two kingdom classification seems to be inadequate. Hence, new system of classification done that includes these characteristics. Further, the invention of the electron microscope that lead to the establishment of the other kingdoms. In 1969, R.H. Whitaker proposed a five Kingdom Classification that include kingdoms: Monera, Protista, Fungi, Plantae and Animalia.
Answer:
The invention of the microscope
Explanation:
The invention of the microscope and the ability to see organisms that are otherwise invisible to the ordinary eye led to the establishment of Monera and Protista kingdoms.
Organisms in the Monera and Protista kingdom are microscopic and the invention of the microscope created and avenue for them to be studied extensively by scientists.
Through their studies, taxonomists discovered that these microscopic organisms have characteristics that are neither of plants nor of animals.
Some organisms were found to lack nucleus and membrane-bound organelles which is unlike plants and animals. Some were also found to posses most of the characteristics of animals except that they are unicellular.
These led to the establishment of the Monera and Protista kingdoms respectively.
