# Chapter 3 Biodiversity in Crisis and Our Daily Lives — Life on the Earth That Runs on to the Future —

## Section 1 Accelerating Loss of Biodiversity

According to the United Nations Millennium Ecosystem Assessment, the present rate of extinction of living organisms has reached 100 to 1,000 times higher than the rate of extinction in the past, and most indicators that show the status of ecosystem services (benefits people can obtain from ecosystems) are exhibiting a

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## What Is Biodiversity?

“Biodiversity,” to put it plainly, is the state of “many living organisms existing by adapting to a variety of environments on the earth, from the abyssal ocean to uplands.” This phrase contains the following three aspects. The existence of diverse types of ecosystems, such as forests, rivers, wetland, tidal flats, coral reefs and oceans, is described as “ecosystem biodiversity,” while the existence of diverse kinds of living organisms in these ecosystems is called “species diversity” and the existence of various genetic variations in the same species, such as differences in body size, pattern or resistance to disease is termed “genetic diversity.”

Let us explore these three aspects more deeply.

Ecosystem diversity means that there exist a variety of environments due to a variety of circulations on the earth. For example, there is the circulation of water in which precipitation that seeps into the ground evaporates through plants and forms clouds to cause rain. In the circulation of material, organic material that goes through consumers by the food chain ultimately returns to inorganic material by decomposers and producers again turn inorganic material into organic material. In the atmospheric circulation, carbon dioxide emitted in association with activities of living organisms on the earth, including human activities, is absorbed by forests that produce oxygen. These diverse circulations, for example, help form small units of specific ponds and forests, which combine to form larger units of basins, and several basins consist of units of archipelagoes and continents, which together constitute the earth, thus establishing various ecosystems on the earth in seamless manners. There exists no identical ecosystem on the earth. This is ecosystem diversity.

Species diversity indicates that there exists about deteriorating trend. This section addresses the impact of biodiversity loss on our daily lives (decreases in products from agriculture, forestry and fisheries industries) and economic loss from declining ecosystem services, and then underscores the need to halt biodiversity loss and enhance biodiversity.

30 million species of various living organisms, including unknown ones, after living organisms have evolved to adapt to various environments on the earth. When kinds of living organisms are diverse, interactions between them are also diverse. There emerge a variety of direct and indirect interactions, from eating, being eaten, parasitizing other living organisms and providing habitats to competing for resources and decomposing dead living organisms. Looking at relationships of eating and being eaten, for example, while there is a manner of utilization in which some species feed on anything that is fit to eat, there is also the relationship based on strong mutual links where a certain insect eats only leaves of a certain plant. The diversity of species is thus based on the existence of various physical environments created by ecosystems, natural selection of species caused by a variety of interactions such relationships between living organisms and physical environments and relationships between living organisms, and genetic differences caused by evolution.

The significance of genetic diversity needs to be considered by keeping in mind that living organisms are the beings that try to survive, by maintaining life as individual organisms or by leaving next generations through procreation. A variety of living organisms we are currently seeing have been created through a long process of evolution. When there are genetic differences among individual living organisms and those differences influence their survival and procreation, which is exactly where evolution starts. Properties that make the survival easier, if only little, are carried forward to next generations. What properties make the survival easier depend on environments surrounding living organisms. Different properties evolve under different environments. In