Human survival: Its biological scenario!

Hirokazu Kobayashi

CEO, Green Insight Japan, Inc.

Professor Emeritus and Visiting Professor, University of Shizuoka

The movie "Dune: Part Two," set in the year 10190, was released in March of this year and has attracted much attention. This is the second movie directed by Denis Villeneuve (1967-) based on the science fiction epic novel "Dune" by Frank Herbert (1920-1986), published in 1965. The first movie was released in 2021. There had been many attempts to make a movie version, but it wasn't easy to express the gravity of the story and the grandeur of the universe, and it was finally realized. In different period settings and perspectives, humanity's future has also been questioned through manga, anime, novels, movies, TV dramas, and other media. At first, these works were grouped under the "science fiction” genre and told of a bright future based on industrial development. The first of its kind can be found in a serialized novel that appeared in the magazine "Modern Electrics" in 1911. "Brave New World" by Aldous Huxley (1894-1963), published in 1932, realistically describes, with humor and irony, a dystopia in which man loses his dignity while enjoying prosperity through the development of a mechanical civilization. But dystopia had already come to pass. In 1878, the Ashio Copper Mine poisoning incident had occurred in Japan. After that, many pollution issues were raised. In 1952, London experienced thick smog caused by coal burning, factory smoke, and diesel emissions. It caused about 12,000 deaths from respiratory disorders, and others suffered many health problems. Also, in 1962, "Silent Spring" by Rachel Carson (1907-1964) was published, denouncing the pollution caused by the overuse of pesticides. From then on, fiction and nonfiction sounded the alarm about humanity's industrial activities. The first Japanese works on the subject were Sawako Ariyoshi's (1931-1984) novel "Compound Pollution" (1975), as well as Hayao Miyazaki's (1941-) animated TV series "Future Boy Conan" (1978) and the animated film "Nausicaä of the Valley of the Wind" (1982). "Future Boy Conan" is based on Alexander Kay's (1904-1979) "The Incredible Tide" (1970).

Ray Kurzweil (1948-) and other futurists predict that technological singularity will occur around 2045. This refers to a time when artificial intelligence will surpass human intelligence and achieve self-perpetuating progress. It is believed that human life and social structures will change dramatically during this period. Climate change is also recognized as significantly impacting humanity throughout the 21st century. The United Nations Intergovernmental Panel on Climate Change (IPCC) report predicts that if greenhouse gas emissions continue at their current rate, the average global temperature will increase by several degrees Celsius, causing extreme weather events, sea level rise, and ecosystem destruction. In addition, according to UN projections, the world's population will reach 9 billion by the middle of the 21st century and then begin to decline. An aging society and declining birth rates are expected to impact the economy and social security systems majorly.

Impacts from asteroids and comets have caused massive damage to life on Earth, posing a risk of human extinction. Technology is being developed to monitor and predict celestial bodies' impact and avoid collisions. Pandemics such as the one we experienced from 2020 to today, as well as emerging infectious diseases. Such prevention and countermeasures are necessary. The existence of nuclear weapons is also one of the greatest threats to the survival of the human race. The risk of nuclear war increased during the Cold War, and concerns remain today about the proliferation of nuclear weapons and their use by terrorists.

Human evolution diverged from Homo erectus to H. heidelbergensis about 1.2 million years ago and from H. heidelbergensis to H. denisovans and H. neanderthalensis about 400,000 years ago. About 300,000 years ago, H. heidelbergensis diverged into us, H. sapiens. H. sapiens was then mixed with some genetic information from H. denisovans, H. neanderthalensis, etc. This mixing overturned conventional thinking. Founding director Svante Pääbo (1955-) of the Max Planck Institute for Evolutionary Anthropology and adjunct professor at Okinawa Institute of Science and Technology (OIST), Japan, was awarded the 2022 Nobel Prize in Physiology or Medicine alone for this achievement. Assuming a human generation lasts 25 years, that would mean 12,000 generations over 300,000 years. During this time, the 3 billion letters of the genetic information that make up human genetic information have mutated to generate diversity to the present day.

The primary definition of "species" in biology is the ability to produce offspring through interbreeding. The "species" that has survived the longest is the so-called "living fossil." About 400 million years ago, the Earth was in the Devonian Period of the Paleozoic Era. The continents of Gondwana, Laurasia, and Siberia existed, and shallow oceans covered the continental shelves. The climate was warm and stable. The Devonian is also known as the "Age of Fish," and the diversity of fish species increased. Nautiluses (Nautilidae), horseshoe crabs (Limulidae), coelacanths (Latimeria), and sea cucumbers (Holothuroidea) were among the marine organisms present at this time. About 350 million years ago, during the Carboniferous-Permian period, ferns (Polypodiopsida) and jumping spiders (Salticidae) appeared among the plants and animals, respectively, and they have retained their characteristics as a species. In these "living fossils," climate change, massive volcanic activity, asteroid impacts, and lack of oxygen in the oceans have not led to species extinction. They did not require significant evolutionary changes and survived under low evolutionary pressure. In other words, adaptation to changing environments is the key to survival, and these creatures have managed to achieve this without altering their bodily mechanisms.

On the other hand, some species have appeared that use tools. Among mollusks, the octopuses (Octopus vulgaris) use coconut shells and seashells to create hiding places. Among crustaceans, the hermit crabs (Pagurus bernhardus) use snail shells to house their bodies. The wrasses (Labridae) use rocks to break open shells in fish. Among reptiles, iguanas (Iguana iguana) use leaves to collect water. Birds, such as the New Caledonian crows (Corvus moneduloides), use leaves and twigs to catch insects and place nuts on roads to be cracked by cars. The palm cockatoos (Probosciger aterrimus) use sticks to extract food. Among mammals, dolphins (Tursiops truncatus) may use sea sponges to protect their noses while foraging on the seabed. Otters (Enhydra lutris) use stones to break open shells. Primates, like chimpanzees (Pan troglodytes), use sticks to catch termites and stones to crack nuts. Orangutans (Pongo pygmaeus) use leaves to shield themselves from rain and sticks to extract honey. Capuchin monkeys (Cebus apella) use stones to crack nuts and leaves to drink water. Humans have also developed similar behaviors.

Curiosity, a trait often associated with humans, also plays a significant role in the adaptive behaviors of various species. Octopuses, king crabs (Paralithodes camtschaticus), iguanas, dogs (Canis lupus familiaris), and cats (Felis catus) are known to exhibit exploratory behavior towards new environments and objects. The African grey parrots (Psittacus erithacus) possess high cognitive abilities and show intense curiosity in problem-solving and communication. Primates exhibit high intelligence and intense curiosity, actively exploring new objects and situations. Humans show a particularly marked curiosity and an inquisitiveness that spans science, art, and technology. This curiosity, often overlooked in the animal kingdom, is a critical factor in the survival of these species in changing environments.

In preparation for the coming ice age, we must first develop a permanent energy supply system to survive for 100,000 years. Therefore, assuming we do not take actions that lead to our destruction, we can overcome environmental changes and the biological characteristics to survive on Earth. If such human wisdom is to be utilized, the 300,000 years of human history after its birth are not nearing the end but are still in their prologue.