2026 Volume 18 Pages 83-98
In recent years, an anthropogenic mass extinction, known as the "Sixth Mass Extinction," has become a serious concern among scientists and naturalists, and is considered one of the major challenges in global biodiversity conservation. Therefore, it is recommended that upper secondary biology courses include learning about the threat of the anthropogenic mass extinction in relation to biodiversity conservation. Since the topic of the anthropogenic mass extinction has similarities to the past five mass extinction events, it is desirable to study the current threat of mass extinction in conjunction with those previous events. However, within the framework of the current Japan’s Upper Secondary School National Curriculum Standard (USS-NCS), current species extinctions are covered in Basic Biology. Past mass extinctions are not covered in biology courses, but rather in earth science courses. The present study aims to investigate how current threat of mass extinction is addressed and explained in relation to past mass extinctions in ten Basic Biology, five Advanced Biology, five Basic Earth Science and one Advanced Earth Science textbooks currently used in Japan. While all ten Basic Biology textbooks refer to anthropogenic disturbances to ecosystems that could be causes of current species extinctions, only two of them briefly address the current threat of mass extinction and only one of them explains it in relation to past mass extinctions. On the other hand, despite not being mentioned in the USS-NCS and its Guidelines, all five Advanced Biology textbooks cover ongoing species extinctions, and three of the five also describe past mass extinctions, but they do not relate current species extinctions to past mass extinctions. Five Basic Earth Science textbooks and the one Advanced Earth Science textbook all cover past mass extinctions. In particular, detailed explanations are provided regarding the mass extinctions that occurred at the Permian-Triassic boundary and the Cretaceous-Paleogene boundary. However, these Earth Science textbooks do not address ongoing species extinctions at all. Currently, while approximately 80% of Japanese upper secondary students study Basic Biology, just over 20% study Basic Earth Science, around 15% study Advanced Biology, and less than a few percent study Advanced Earth Science. This means that, conservatively speaking, more than half of upper secondary students in Japan are unable to have the opportunity to learn about the ongoing species extinction in connection with the past five mass extinction events through science textbooks. Consequently, it would be desirable to incorporate more information on current species extinctions and past mass extinctions in Basic Biology classes to make students aware that the current species extinctions will possibly be on the same scale as the past five mass extinctions.
While species extinction is a natural phenomenon characteristic of evolution throughout the history of life, it can also reduce biodiversity (Turvey and Crees, 2019). As a natural background rate to the timing and frequency of extinctions, it is estimated that about 10% of species are lost every million years, 30% every 10 million years, and 65% every 100 million years (Raup, 2016; Ritchie, 2022, see the Website List). Throughout the history of life, large-scale extinctions, or mass extinctions, have occurred at infrequent intervals, caused by some kind of natural disturbance such as ocean acidification from intense volcanic activity (Li et al., 2023), and an asteroid impact followed by rapid and dramatic changes in climate (Henehan et al., 2019). A mass extinction is an event that occurs within a relatively short period of geological time, less than two million years, have resulted in the extinction of at least 75% of species (Ritchie, 2022).
An increase in species extinctions on a global scale in recent years is thought to be the result of the globalization of human activities. Thus, the possibility of an anthropogenic mass extinction, known as the "Sixth Mass Extinction" (or the "Anthropocene extinction" or "Holocene extinction"; ‘Sixth Mass Extinction’ hereafter), is recognised as a serious concern among scientists and naturalists (e.g., McCallum, 2015; Cowie et al., 2022; Finn et al., 2023). Climate change, pollution, habitat loss, invasive species, and overexploitation are considered to be the five most important "direct causes" of such species extinctions leading to biodiversity loss currently of concern (Cafaro, 2015; Kleespies et al., 2024). Some sceptics claim that the ongoing extinction of species will not reach a scale comparable to past mass extinctions (e.g., Kaiho, 2022), or that there are conceptual issues in defining mass extinctions and uncertainties in past and present biodiversity assessments (e.g., Bocchi et al., 2025). However, the threat of the Sixth Mass Extinction remains one of the major challenges in global biodiversity conservation (Cowie et al., 2022; Crist, 2022).
Wagler (2011), taking the position that we are currently in the Sixth Mass Extinction, proposes incorporating an overview of the current mass extinction in conjunction with past and present human activities, along with the previous five mass extinction events, into the science education curriculum. Reice (2024) also suggests that it is desirable to raise students' awareness of the threat of the Sixth Mass Extinction in biology classes from the perspective of global biodiversity conservation. However, while several research reports on how to deal with the current threat of mass extinction in biology education at schools have been published in the United States (Wagler, 2013; Cohen, 2016; Wagler, 2018; Cohen and Mark, 2021; Wollmuth et al.,2022), it seems that this topic has not yet been widely explored in Japan or other countries in the Asia-Pacific region.
In Japan, under the current Upper Secondary School National Curriculum Standard (MEXT, 2018; ‘USS-NCS’ hereafter), biology education is conducted through two subjects: Basic Biology and Advanced Biology. Basic Biology has a section titled "Ecosystems and Diversity of Organisms" in Unit 3 "Diversity of Organisms, and Ecosystems" (APPENDIX 1) where students learn about current species extinctions and anthropogenic ecosystem disturbances that can lead to the loss of biodiversity (MEXT, 2021b). Advanced Biology has a section titled "Phylogeny and Evolution of Organisms" in Unit 1 "Evolution," and a section titled "Ecosystems and Human Life" in Unit 5 "Community and Its Environment" (APPENDIX 2). The former section could potentially deal with past mass extinctions that are thought to have accelerated evolution in the history of life (Jablonski, 2001), while the latter section could potentially cover current species extinctions related to the decline of biodiversity. However, the USS-NCS (MEXT, 2018) and its Guidelines (MEXT, 2021b) make no mention of how past mass extinctions and current species extinctions should be treated in these sections. To fully understand the topic of the Sixth Mass Extinction, it is essential to study the previous five mass extinctions (Wagler, 2011), because its rate of progression is approaching that of past mass extinctions (Barnosky et al., 2011; Ceballos et al., 2015). However, at the USS-NCS, past mass extinctions are not covered in biology courses. They are covered in earth science courses, namely in Basic Earth Science and Advanced Earth Science. In Basic Earth Science, an overview of the paleontological evolution and changes in the Earth’s environment throughout the geological era is to be taught in the section "Paleontological Evolution and the Global Environment" of Unit 2 "The Changing Earth." In Advanced Earth Science, the evolution of organisms throughout geological time, including the five large-scale extinctions and subsequent emergence of distinctive animal groups, is to be taught in the section titled "Changes in the Global Environment" of Unit 2 "Earth's Activity and History" (APPENDIX 3). However, the USS-NCS Guidelines do not mention how to address the topic of ongoing species extinction in earth science courses at all. Thus, the current USS-NCS and its Guidelines do not link current species extinctions to past mass extinctions. In principle, textbooks used in Japanese schools must be produced in accordance with the National Curriculum Standards and their Guidelines. However, since textbook compilers (private publishers) are expected to create textbooks with originality and ingenuity (MEXT, undated; see the Website List), they are permitted to include content not explicitly specified therein. How, then, do current biology and earth science textbooks address current species extinctions and past mass extinctions?
In this study, biology and earth science textbooks currently used in Japanese upper secondary schools were investigated to clarify how the threat of Sixth Mass Extinction is treated in relation to past mass extinctions. In addition, whether the five most important direct causes of current biodiversity loss mentioned by Cafaro (2015) and related events are mentioned in these textbooks and whether these are described in relation to biodiversity loss were investigated. This paper reports the results of the textbook survey, and based on the survey results, discusses how the threat of the Sixth Mass Extinction should be treated in upper secondary school biology courses from the perspective of global biodiversity conservation education. Although this study focuses specifically on upper secondary school science education in Japan, further research is required to determine whether the curricular issues raised herein are also applicable to high school science curricula in other Asia-Pacific countries.
While mass extinctions are important in the evolution of organisms (Jablonski, 2001) and are an important topic in evolutionary education (Wyner and DeSalle, 2019), they are beyond the scope of this paper.
Please note that this paper does not cover the timing or potential causes of past mass extinctions. For an overview of past mass extinctions, I would recommend consulting the online paper by Ritchie (2022).
The textbook survey used ten Basic Biology textbooks published in 2022 and five Advanced Biology textbooks published in 2023 (See the list in the “BIOLOGY TEXTBOOKS SURVEYED” at the end of the paper), as well as five Basic Earth Science textbooks published in 2022 and one Advanced Earth Science textbook published in 2023 (See the list in the “EARTH SCIENCE TEXTBOOKS SURVEYED” at the end of the paper). All of these textbooks are approved to be used as textbooks at schools through the Textbook Authorization process (MEXT, undated, see the Website List) the year before their publication. In this paper, each textbook will be referred to by its subject abbreviation and number.
The textbook survey focused on sections corresponding to the USS-NCC items indicated in bold within the tables in APPENDIX 1 – 3. From the sections of the textbooks surveyed, terms, phrases and charts related to extinction, extinct species, and the five most important "direct causes" of current biodiversity loss mentioned by Cafaro (2015) and events related to them, were collected. In this process, not only gathering the relevant terms and phrases, but also checking the presence of explanatory text or diagrams regarding these topics was conducted. For collecting extinct species names two reports by Katayama (2025, 2026) were utilised. The method for analysing the descriptions and explanations of terms, sentences and charts collected from textbooks followed that used by Katayama (2025). The English translations of collected terms in this paper are based on Katayama and Nakamichi (2024) and Katayama (2025).
Katayama and Nakamichi (2024) and Katayama (2025) have reported that all ten Basic Biology textbooks include explanations of current species extinctions. These descriptions are generally explained within the context of how species extinctions reduce local biodiversity, and almost all textbooks point out that the extinction rate has grown in recent years. Almost all Basic Biology textbooks list and explain the five most important "direct causes" of biodiversity loss, as listed by Cafaro (2015), or those thought to be related to them (Table 1). While these are contributing factors to ongoing species extinction, textbooks often treat them merely as examples of anthropogenic disturbances of ecosystems, failing to clearly point out their connection to species extinction and, the resulting loss of biodiversity.
| Cause* | Basic Biology textbook | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| BB1 | BB2 | BB3 | BB4 | BB5 | BB6 | BB7 | BB8 | BB9 | BB10 | |
| 1 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 |
| 2 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 |
| 3 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | △ |
| 4 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 |
| 5 | 〇 | △ | 〇 | 〇 | X | △ | 〇 | 〇 | 〇 | 〇 |
* Cause 1: Habitat loss (forest logging, habitat fragmentation, land cleaning, slash and burn cultivation); Cause 2: Impact of invasive alien species; Cause 3: Overexploitation (overhunting, overfishing, excessive logging); Cause 4: Pollution (air pollution, water pollution, eutrophication, microplastic pollution); Cause 5: Climate change (global warming, desertification). The terms in parentheses are representative ones related to each respective cause which are listed in the textbooks surveyed.
X: No mention of the topic; △: Listing of topic-related terms only; 〇: Inclusion of explanatory text or diagrams regarding the topic.
Three textbooks (BB1, BB2 and BB10) briefly state that, as Jablonski (2001) and Ritchie (2022) have mentioned, species extinction has always occurred throughout the history of life, and Textbooks BB1 and BB2 further state that it is a phenomenon related to the evolution of organisms. However, none of these three textbooks provide specific descriptions of past mass extinctions. Textbooks BB7 and BB8 briefly address the threat of current mass extinction, however, only Textbook BB7 states “Extinctions are occurring at an alarming rate... It is believed that there have been five mass extinctions on Earth in the past; the present is said to be the sixth (Textbook BB7, p. 206)” in a reference column．But even that textbook does not provide detailed explanations about the past five mass extinctions events, such as their scales or causes.
As Katayama and Nakamichi (2024) have reported, all ten Basic Biology textbooks include the term "extinction" in their indexes, and seven out of the ten treat it as a key term. However, the term "mass extinction" is only used in the Textbooks BB7 and BB8, and it is not included in the index or treated as a key term.
Content related to extinctions in Advanced Biology textbooksThe USS-NCS Guidelines (MEXT, 2021b) do not specify how to deal with past mass extinctions or current species extinctions in the Advanced Biology course. However, three Advanced Biology textbooks cover the Phanerozoic mass extinctions and two cover a Precambrian mass extinction to some extent in the section "Phylogeny and Evolution of Organisms" (Table 2). Among them, Textbook AB3 provides the most detailed description of the Phanerozoic mass extinctions, explaining each of the five mass extinction events. Textbooks AB2 and AB4 mention only two mass extinctions that occurred at the end of the Permian period and Cretaceous periods. However, none of those textbooks address the causes of these mass extinctions. Textbooks AB4 and AB5 mention a mass extinction of anaerobic microorganisms in the Precambrian age and state that it is thought to have been caused by oxygen produced by photosynthesis in cyanobacteria (AB4, p. 17; AB5, p. 23). Textbook AB1 only shows a diagram of the evolution of life over the past 3.5 billion years and makes no mention of past mass extinction events in the corresponding section.
| Topic | Advanced Biology textbook | ||||
|---|---|---|---|---|---|
| AB1 | AB2 | AB3 | AB4 | AB5 | |
| Past five mass extinctions | X | △* | 〇 | △* | X |
| Mass extinction(s) during the Precambrian age | X | X | X | 〇 | 〇 |
| Current species extinctions | 〇 | 〇 | 〇 | 〇 | 〇 |
| Threat of the Sixth Mass Extinction | 〇 | △* | X | X | △* |
|
X: No mention of the topic; △: Merely list related terms or provide only partial explanations; 〇: Explanatory text or diagrams regarding the topic are included. * Refer to the further explanation in the main text. |
|||||
All Advanced Biology textbooks deal with species extinction in the unit "Community and Its Environment" and relate it to the direct or indirect impacts of human activities (Table 2). However, despite the USS-NCS guidelines recommending that the impact of human activities should be viewed on a global scale in Advanced Biology (MEXT, 2021b), all Advanced Biology textbooks again primarily mention the extinction of species native to Japan which is already covered in Basic Biology textbooks (Katayama, 2026). Textbooks AB1, AB2 and AB5 mention the current species extinctions in relation to the threat of mass extinction (Table 2). Textbooks AB2 and AB5 cite the 2019 report by IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services), stating that approximately one million species worldwide are at risk of extinction. As mentioned above, Textbook AB1 contains no information on past mass extinctions in its "Phylogeny and Evolution of Organisms" section, but in the unit "Community and Its Environment," it states: “In the last 500 years, it is estimated that more than 300 species of vertebrates have gone extinct (p. 370),” and “If no measures are taken, it is predicted that in the near future, a number of species comparable to those in past mass extinctions will become extinct due to the effects of land transformation, eutrophication, invasion of alien species, and global warming. This is different from the impacts of natural processes such as meteorite impacts or continental drift, as was the case with past mass extinctions (p. 437).” However, this textbook does not provide any further information, such as the scale or causes of past mass extinctions. The other Advanced Biology textbooks do not refer to past mass extinction events when describing current species extinctions.
As shown in Table 3, Textbook AB1, AB3 and AB5 list all the five most important direct causes of biodiversity loss, as listed by Cafaro (2015), and point out that they contribute to species extinction or biodiversity decline. However, while the other two textbooks mention the link between causes 1, 3 and 5 and species extinction, they do not describe the connection between the cause 4 and species extinction, and they also lack a topic on invasive alien species (cause 2).
| Cause* | Advanced Biology textbook | ||||
|---|---|---|---|---|---|
| AB1 | AB2 | AB3 | AB4 | AB5 | |
| 1 | 〇 | 〇 | 〇 | 〇 | 〇 |
| 2 | 〇 | X | 〇 | X | 〇 |
| 3 | 〇 | 〇 | 〇 | 〇 | 〇 |
| 4 | 〇 | △* | 〇 | △* | 〇 |
| 5 | 〇 | 〇 | 〇 | 〇 | 〇 |
|
* Cause 1: Habitat loss (forest logging, habitat fragmentation, land cleaning, slash and burn cultivation); Cause 2: Impact of invasive alien species; Cause 3: Overexploitation (overhunting, overfishing, excessive logging); Cause 4: Pollution (air pollution, water pollution, eutrophication, microplastic pollution); Cause 5: Climate change (global warming, desertification). The terms in parentheses are representative ones related to each cause which are listed in the textbooks surveyed. X: No mention of the topic; △: Listing of topic-related terms only; 〇: Inclusion of explanatory text or diagrams regarding the topic. * Refer to the further explanation in the main text. |
|||||
While the term "extinction" appears in all five Advanced Biology textbooks (Katayama and Nakamichi, 2024), only two textbooks (AB2 and AB3) list it in their indexes and one of them (AB3) treats it as a key term. The term "mass extinction" appears in four textbooks (AB1, AB2, AB3 and AB4), but only Textbook AB3 lists it in its index but not treat it as a key term.
Content related to extinctions in Basic Earth Science and Advanced Earth Science textbooksThe USS-NCS Guidelines (MEXT, 2021b) do not specify how mass extinctions in geological time are to be treated in Basic Earth Science, but all five Basic Earth Science textbooks include content on past mass extinctions in the section "Paleontological Evolution and the Global Environment." Each textbook states that at least five mass extinctions have occurred in geological time. To indicate this, Textbooks BE1 and BE3 use diagrams from Sepkoski, Jr. (1997) and Palmer (1999), respectively. Textbooks BE2 and BE5 use a chart of the geological timeline, adapted from the International Chronostratigraphic Chart v 2019/05 (International Commission on Stratigraphy, 2019) and the International Chronostratigraphic Chart v 2020/01 (International Commission on Stratigraphy, 20209), respectively. Textbook BE4 uses both the diagram from Sepkoski, Jr. (1996) and a geological timeline adapted from the International Chronostratigraphic Chart v 2019/05. However, while the mass extinctions that occurred at the end of the Permian period (Permian-Triassic boundary) and the end of the Cretaceous period (Cretaceous-Paleogene boundary) are explained in detail or to some extent in all five Basic Earth Science textbooks, the other three mass extinctions are merely explained briefly (Textbook BE4) or are mentioned without any explanation (Table 4). Regarding mass extinctions that are believed to have occurred during the Precambrian age, every Basic Earth Science textbook briefly mentions the extinction of the Ediacaran biota.
| Term / Content | Earth Science textbook | |||||
|---|---|---|---|---|---|---|
| BE1 | BE2 | BE3 | BE4 | BE5 | AE1 | |
| Term "mass extinctions"* | ● | ● | 〇● | 〇 | 〇 | 〇 |
| Term " Late Permian Extinction"* | ● | △ | △ | △ | △ | △ |
| Term " Late Cretaceous Extinction"* | ● | △ | △ | △ | △ | △ |
| Topic "Five mass extinctions"** | △ | △ | △ | 〇 | △ | △ |
| Topic "The Late Permian Extinction"** | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 |
| Topic "The Late Cretaceous Extinction"** | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 |
| *△: The term appearing only in the main text;〇: The term included in the index; ●: The term treated as a key term.** △: The topic is mentioned by term or indicated in a diagram; 〇: Explanatory text regarding the topic is included. | ||||||
All textbooks include the terms "extinction" and "mass extinction" in the text, but none of them includes the former term in their indexes or treats it as a key term. The treatment of the term "mass extinction" and "Permian-Late Extinction (Permian-Triassic mass extinction)" and "Cretaceous-Late Extinction (Cretaceous-Paleogene mass extinction)" differs in each of five Basic Earth Science textbooks as shown in Table 4. In both Basic Biology and Advanced Biology textbooks all key terms are included in their indexes (Katayama and Nakamichi, 2024), but in Basic Earth Science textbooks terms are treated differently.
Currently there is only one Advanced Earth Science textbook (AE1), which is published by the same publisher as the Basic Earth Science textbook BE3. In this textbook, the content on past mass extinctions is covered in Section 2 "Evolution of Life" of Chapter 2 "History of Earth, and Life and the Environment." The content is not significantly different from the Basic Earth Science textbook BE3, indicating the past five mass extinctions by showing a diagram quoted from Raup and Sepkoski, Jr. (1982). It also includes a topic of mass extinction in the Precambrian age. Although the terms "extinction" and "mass extinction" are used in the text, only "mass extinction" is included in the index, and it is not treated as a key term (Table 4).
All Basic Earth Science and Advanced Earth Science textbooks do not cover any topics of ongoing species extinctions.
Species that went extinct in recent years possibly caused by human activity mentioned in biology textbooksKatayama (2025, 2026) reported a few extinct species (extinct: EX, and extinct in the wild: EW) are listed in Basic Biology textbooks and Advanced Biology textbooks. All of these species are thought to have become extinct relatively recently. In many cases, textbooks that cover these extinct species either list them on an endangered species list or simply include a photograph along with their name, without explaining the possible cause of their extinction. The extinct species listed with a specific explanation of the cause of extinction in Basic Biology and Advanced Biology textbooks are Ectopistes migratorius (passenger pigeon, EX), Canis lupus hodophilax (Japanese wolf, EX), Lutra lutra nippon / Lutra lutra whiteleyi (Japanese otter, EX), Thylacinus cynocephalus (thylacine, EX), and Ceratotherium simum cottoni (northern white rhinoceros, EW). Textbooks BB7 and BB8 cite the passenger pigeon as an example of extinction caused by overhunting. Textbook AB1, which lists the Japanese wolf, the Japanese otter and Raphus cucullatus (dodo, EX), states that the extinction of the first two is thought to be due to overhunting and habitat loss but regarding the dodo, it does not specify the cause of extinction, noting only that it resulted from the impact of human activity. Textbook AB3 cites the thylacine as an example of a native species that went extinct due to competition for resources with invasive alien species, the dingo <According to the Natural Museum Australia (2025, see the Website List), this applies only to the population on the Australian mainland; the Tasmanian population went extinct due to different factors - primarily overhunting>. Textbook AB5 cites the northern white rhinoceros as an example of an organism endangered by demographic probabilities (a drastic decline in population and difficulty in reproduction because of most offspring being of the same sex), but it does not explain the specific causes of such extreme population decline.
Six Basic Biology textbooks (BB1, BB2, BB3, BB4, BB5 and BB8), and two Advanced Biology textbooks (AB1 and AB2) list Nipponia nippon (Japanese crested ibis) and three Basic Biology textbooks (BB6, BB7 and BB8) list Ciconia boyciana (Japanese white stork). These birds are classified as CR (critically endangered) on the Red List provided by the Ministry of the Environment <MOE> (MOE, 2020), but due to overhunting, pesticide pollution and habitat changes, their native Japanese populations went extinct quite recently and were reintroduced from Russia (MOE Kinki Regional Environmental Office, 2009; see the Website list) and China (Sado City, 2012), respectively. However, while textbooks describe conservation efforts for these birds, no textbooks give an adequate explanation of the causes of their extinction. On the Japanese crested ibis, Textbook BB1 explains the bird has been propagated by captive breeding, Textbooks BB4 and AB1 explain the effort to reintroduce the bird in Japan. Textbook BB8 lists the Japanese white stork as an example of reintroduction into the wild. Textbook BB8 introduces these two species as examples of “Agricultural Products with Animal Marks” with their photos.
Content on species extinctions caused by human activity in prehistoric times in biology and earth science textbooksThis topic is not covered in either biology textbooks or earth science textbooks surveyed. The emergence of early hominins is thought to have occurred in the late Neogene period, or the Miocene epoch (Begun, 2004). All of Basic Earth Science and Advanced Earth Science textbooks include a section on "Emergence and Evolution of Humankind," which explains the evolution of humankind starting with Sahelanthropus. However, the impact of humans on the extinction of large vertebrates (megafauna) is either only briefly mentioned, such as “...based on evidence such as stone tools, it is believed that Neanderthals hunted large animals using weapons such as spears...” (Textbook BE1, p. 121) or not mentioned at all. Similarly, Advanced Biology textbooks have a section on "Phylogeny and Evolution of Humans" and briefly describe the history of humankind, but none of them mention mass extinctions of megafauna possible caused by human activity in prehistoric times.
While there are several reports on teaching methods, content and available resources regarding ongoing biodiversity loss (i.e., the Anthropocene extinctions) in US school biology (Wagler, 2011; Wagler, 2013; Cohen, 2016; Wagler, 2018; Cohen and Mark, 2021; Wollmuth et al.,2022), there are no reports on such topics in Japanese school biology education. Therefore, I investigated what information on mass extinction events is included in upper secondary school biology and earth science textbooks currently used in Japan.
The results of the textbook survey revealed that while Basic Biology textbooks explain current species extinctions, they do not necessarily address their connection to anthropogenic disturbance of ecosystems. Furthermore, since most of the textbooks provide little to no information about past mass extinctions, they fail to explain the current species extinctions in relation to past mass extinctions. Only one (Textbook BB7) out of ten Basic Biology textbooks indicates the rate of current extinctions of species is comparable to the past mass extinctions. On the other hand, five Basic Earth Science textbooks and one Advanced Earth Science textbook all explain the past mass extinctions, particularly those occurred at the Permian-Triassic boundary and the Cretaceous-Paleogene boundary, but contain no mention of the ongoing species extinctions. Three of the five Advanced Biology textbooks cover both past mass extinctions and current species extinctions, while only two point out the possibility that the ongoing species extinctions could lead to mass extinction comparable to past mass extinctions. Judging from the content explained and the terminology used, most biology textbooks seem to place importance on current species extinction, but less on mass extinction that may result. On the other hand, all earth science textbooks place importance on the connection between past mass extinctions and drastic changes in the Earth's environment, as well as the changes in biota that followed mass extinctions. These textbooks emphasise when these events occurred in geological history by citing diagrams showing biotic changes on a geological timescale and chronologies of geological time.
Based solely on textbook content, only Advanced Biology textbooks are useful to some extent for making students aware that, as several paleontologists (e.g., Ceballos et al., 2015) have pointed out, current species extinctions could reach the same scale as past mass extinctions. However, in the current Japan’s upper secondary school science curriculum framework, basic subjects are for all students, while advanced subjects are offered to the students who are interested in a particular field of science (Nakamichi and Katayama, 2018). Furthermore, advanced subjects are typically taken after completing basic subjects. Within such a science curriculum framework, the threat of the Sixth Mass Extinction should be addressed in basic subjects rather than advanced ones. This is because it is desirable for all upper secondary school students to be aware of how serious the Sixth Mass Extinction would be and the necessity of preventing its progression for the sake of all life on Earth, including ourselves.
According to the data released by MEXT (2026), the estimated enrolment rates for upper secondary school science subjects (average of 2024 and 2025 academic years) are 77%, 23%, 15%, and 1% respectively for Basic Biology, Basic Earth Science, Advanced Biology, and Advanced Earth Science. If students were to choose only one of either Basic Biology, whose textbooks cover current species extinctions but not past mass extinctions, or Basic Earth Science, whose textbooks cover past mass extinctions but not current species extinctions, they are unable to learn from textbooks the link between ongoing species extinctions and past mass extinctions. Considering the current upper secondary school science curriculum framework and the enrolment rate in science subjects mentioned above, it is recommended to teach past mass extinctions and current species extinctions together in Basic Biology.
As many research papers have pointed out, the current large-scale extinction differs from past mass extinctions in that it is caused by human activity (e.g., McCallum, 2015; Cowie et al., 2022; Ritchie, 2022; Finn et al., 2023). According to Turvey and Crees (2019), by the end of the Pleistocene, approximately 12,000 years ago, humans likely caused the extinction of nearly two-thirds of the world’s mega (>44 kg) vertebrates, probably due to overhunting and/or habitat changes. In Australia, a mass extinction of large animals occurred during the last glacial period, 40,000 to 50,000 years ago, and the causes are thought to be, in addition to climate change, overhunting by indigenous people and habitat change caused by their use of fire and logging (Wallis, 2025). Of course, natural disturbances such as climate fluctuations resulting from glacial-interglacial cycles or geomagnetic reversals (e.g., Wroe et al., 2006) might be the causes of species extinctions. However, when considering why large vertebrates, such as mammoths, - survivors of earlier climate fluctuations - went extinct so quickly following the emergence of humans and their entry into new lands, one is compelled to place significant weight on the direct or indirect effects of human activities (e.g., Burney et al., 2005). To understand the potential anthropogenic mass extinction event, we may need to trace the history of species extinction back to prehistoric times and learn how it continues to the present day. However, in Japan, species extinctions thought to have been caused by human activity in prehistoric times are little mentioned in current biology or earth science textbooks. In which subject should the extinction of prehistoric megafauna, which is thought to have been caused by human activity, be covered - biology or earth science? This topic could be mentioned in relation to the section on "The Emergence and Evolution of Humankind" in an earth science class, or in the section on "The Phylogeny and Evolution of Humankind" in a biology class. In addition, in the current USS-NCS, there is a section in the subject Advanced World History titled "Human History from the Perspective of the Global Environment" which deals with the origin of humankind and its global dispersal and migration (MEXT, 2021a), so as Reiss (2024) has pointed out, it should be considered to cover this topic in history courses as well. The current USS-NCS has a compulsory course called “the Period for Inquiry-Based Cross-Disciplinary Study” in which students are asked to make a plan on their own projects (MEXT, 2018). Considering that anthropogenic extinctions began in the Pleistocene epoch, the theme of the Sixth Mass Extinction is interdisciplinary, encompassing biology, earth science, and world history, making it a suitable topic for their project in this course. When students undertake a project on this topic, the method proposed by Wallis (2025) of searching for traces of mammalian species that once inhabited a certain region but became extinct due to human activities will be useful.
When teaching about the ongoing extinction of species in upper secondary school biology classes, it would be desirable to explain the following points:
• The current rate of species extinctions is approaching the rates of the past five mass extinctions.
• Current species extinctions began at least before the Earth entered the Holocene epoch.
• Unlike the past five mass extinction events, the present species extinction event is an anthropogenic phenomenon.
• The major factors contributing to the current species extinctions are all anthropogenic: global warming (climate change), habitat changes, pollution, invasive alien species, and overexploitation.
• Therefore, unless we ourselves mitigate the factors contributing to the ongoing species extinction, the Sixth Mass Extinction will become inevitable.
These considerations should help raise students’ awareness of global biodiversity conservation. To enable such instruction in upper secondary school biology classes, it will be necessary to revise the USS-NCS and its Guidelines. I earnestly hope that this will be realized in the upcoming revision of Japan's USS-NCS. Furthermore, I hope that other nations will look to Japan's current shortcomings as a reference when revising their own biology curricula.
Finally, although it is not the primary subject of this paper, I would like to briefly address the treatment of ongoing species extinction within the context of evolution education. Wagler (2013) has proposed to incorporate the Anthropocene extinctions and related topics into evolution education. According to Cohen and Mark (2021), the USA’s current Next Generation Science Standards indicates that the unit on evolution in life science curriculum must include the concepts of geologic ages, endangered species, Anthropocene extinctions, and biodiversity. Since past mass extinctions are thought to have promoted biological evolution, it is important to address mass extinction events during geological time in teaching evolution. However, when teaching about ongoing species extinctions, or the Sixth Mass Extinction, in relation to evolution, as Wyner and DeSalle (2019) have pointed out, care must be taken to avoid students’ misunderstandings such as “Ongoing species extinctions and subsequent mass extinctions are not necessarily undesirable phenomena, because past extinctions have facilitated the evolution of life.”
Part of this paper was presented at the 2025 Annual Meeting of the Korean Society of Biology Education held in Busan in December 2025. This research was conducted with no funding. There is no conflict of interest to note. In the preparation of this paper, no actions were taken that violated AJBE Publication Rules and Ethics.
The author would like to express his sincere gratitude to Professor Robert Wallis of Federation University, Australia, for carefully reading the manuscript of this paper and providing valuable suggestions toward its completion.
| Unit | Chapter | Section |
|---|---|---|
|
1. Characteristics of Organisms |
2. Genes and Their Function |
1.1. Unity and Diversity of Organisms 1.2. Organisms and Their Energy 2.1. Genetic Information and DNA 2.2. Genetic Information and Protein Synthesis |
|
2. Regulation of Human Body |
1. Regulations by Nervous and Endocrine Systems 2. Immunity |
1.1. Transmission Mechanism 1.2. Maintenance Mechanism of Internal Environment 2. Immunity mechanism |
|
3. Diversity of Organisms, and Ecosystems |
1. Vegetation and Succession 2. Ecosystems and Their Conservation |
1. Vegetation and Succession 2.1. Ecosystems and Diversity of Organisms 2.2. Balance in Ecosystems and their Conservation |
| (Nakamichi et al., 2023) | ||
| Unit | Chapter | Section |
|---|---|---|
| 1. Evolution |
1. Origin of Life and Evolution of Cells 2. Alteration of Genes and Mechanism of Evolution |
1.1. Origin of Life and Evolution of Cells 2.1. Alteration of Genes 2.2. Changes in Gene Combination |
| 3. Phylogeny and Evolution of Organisms |
3.1. Phylogeny and Evolution of Organisms 3.2. Phylogeny and Evolution of Humans |
|
| 2. Life Phenomena and Biomolecules |
1. Cells and Biomolecules 2. Metabolic Activities |
1.1. Biomolecules and Their functions in Cells 1.2. Roles of Proteins in Life Phenomena 2.1. Respiration 2.2. Photosynthesis |
| 3. Gene Expression and Ontogeny |
1. Genetic Information and Its Expression 2. Ontogeny and Gene Expression 3. Genetic Engineering |
1.1. Genetic Information and Its Expression 1.2. Regulation of Gene Expression
2. Ontogeny and Gene Expression 3. Genetic Engineering |
| 4. Responses to Environmental Stimuli |
1. Responses of Animal and Its Behaviour 2. Responses of Plant to Environmental Stimuli |
1.1 Reception of Stimuli and Reactions 1.2 Animal Behaviour
2. Responses of Plants to Environmental Stimuli |
| 5. Community and Its Environment |
1. Population and Community 2. Ecosystems |
1.1. Population 1.2. Community
2.1. Matter Production and Cycle of Matter in an Ecosystem 2.2. Ecosystems and Human Life |
| (Nakamichi et al., 2023) | ||
| Basic Earth Science | ||
|---|---|---|
| Unit | Chapter | Section |
| 2. The Changing Earth | 1. Evolution of the Earth | 1.1. The Birth of the Universe, Solar System, and Earth |
| 1.2. Paleontological Evolution and the Global Environment | ||
| Advanced Earth Science | ||
|---|---|---|
| Unit | Chapter | Section |
| 2. Earth's Activity and History |
1. Earth's Activity 2. Earth's History |
2.1. Changes in the Earth's Surface |
| 2.2. Observation of Strata | ||
| 2.3. Changes in the Global Environment | ||
| 2.4. Formation of the Japanese Archipelago | ||
(MEXT, 2018)
