2015 Volume 55 Issue 3-4 Pages 149-159
It is an important and intriguing question how complicated eukaryotes had evolved from relatively simple prokaryotes. Although endosymbiotic theory explains the evolution of mitochondria and chloroplasts, and is widely accepted, the origin of the eukaryotic nucleus remains unclear. The endosymbiotic theory is mentioned in all ofthe relevant Japanese high school textbooks, including Basic Biology (Seibutsu Kiso)and Advanced Biology (Seibutsu), under the present Course of Study, and in previous textbooks, including Biology I (Seibutsu I) and Biology II (Seibutsu II). However, hypotheses regarding the origin of the nucleus are not well addressed in any of these textbooks. The origin of eukaryotes, when it is addressed at all, is kept separate from a description of theories related to the three domains, in spite of Archaea, one of those three domains, being regarded as the original host for the original bacterialmitochondrial and chloroplast symbionts. Therefore, it should be important to reconsider textbook descriptions of these topics to increase secondary education's effectiveness regarding the origin of eukaryotes and the three domains. Furthermore,teaching materials regarding the origin of eukaryotes are inadequate, both in Japanand abroad, suggesting that studies for improving these materials are essential.
