Introduction

There is no need to explore a rain forest or beneath the sea, with a microscope or technological equipment, to comprehend the magnificent variety of life on Earth. All you need to do, is look at the plant and animal species around you in order to realize that you live in a world along with living things of all kinds. However, most people either ignore this fact or feel no need to think about it, and thus fall into a serious error, because biodiversity is essential to the countless balances on Earth and to human life. To obtain a better understanding of its importance, consider what we obtain thanks to different forms of life and what we would lose if they were to disappear.90

From birth to death, we humans make use of these micro-organisms, both plants and animals, but pay them nothing in return. Ruth Patrick, an expert on biological diversity of the Philadelphia Academy of Natural Sciences, describes how what living things give us is truly priceless:

... the presence of a great number of species with different structures, different chemical compositions, and different lifespan form one of the most important bases of life for humans throughout our planet. 91

The well-known Stanford University Professor of Biology Paul Ehrlich expresses the same idea in these words:

... microorganisms, plants, and animals play in providing free ecosystem services, without which society in its present form could not persist. 92

Paul Raven, a professor of biology and expert on biodiversity, describes how living things play a vital role in making the Earth a planet fit for human life:

Human existence depends inextricably on other life forms. All humans need Earth's flora, fauna, and microorganisms for sustenance, materials, energy, and even the air they breathe. 93

Professor Bryan Norton of South Florida University refers to the value of the species richness on Earth:

The value of biodiversity is the value of everything there is. It is the summed value of all the GNPs of all countries from now until the end of the world. We know that, because our very lives and our economies are dependent upon biodiversity. If biodiversity is reduced sufficiently, and we do not know the disaster point, there will no longer be any conscious beings. With them will go all value—economic and otherwise. 94

We can witness the benefits we obtain from the plant animal species around us every day. However, there are also countless living things we cannot see with the naked eye, or which we know nothing about. Professor Paul Ehrlich makes the following comment:

... the basic point is that organisms, most of which are obscure to nonbiologists, play roles in ecological systems that are essential to civilization. 95

Advances in technology have revealed a number of facts concerning the importance of the diversity on Earth. Many living things that were previously regarded as unimportant or useless provide human beings with new blessings. For example, a peculiar-looking marine worm contains chemical substances used in the treatment of sick people. Or consider the recently discovered bacteria species that promise great benefits for humanity. For example, one species of bacteria found in the Potomac River in the USA can break down the chlorofluorocarbon gasses that damage the ozone layer.96 And the bacterium Thermus aquaticus, discovered in the thermal springs in America's Yellowstone National Park, played a significant role in the advancement of genetic science.97 Thanks to an enzyme obtained from this micro-organism, the polymerase chain reaction (PCR) technique was developed—an inseparable component of the Human Genome Project, genetic testing and genetic analysis. This made it possible for the process of producing DNA profiles, which had taken weeks back in the 1980s, to be performed in a much shorter time.98

Living things make countless contributions to the ecosystems and balances on Earth, not just to human life. These contributions' importance and complexity are described with an example in an article titled "Ecosystem Services' Benefits Supplied to Human Societies by Natural Ecosystems" written by 11 recognized experts99 from various American universities:

Imagine, for example, human beings trying to colonize the moon. Assume for the sake of argument that the moon had already miraculously acquired some of the basic conditions for supporting human life, such as an atmosphere, a climate, and a physical soil structure similar to those on Earth. The big question facing human colonists would then be, which of Earth's millions of species would need to be transported to the moon to make that sterile surface habitable?

One could tackle that question systematically by first choosing from among all the species exploited directly for food, drink, spices, fiber, timber, pharmaceuticals, and industrial products such as waxes, rubber, and oils. Even if one were highly selective, the list could amount to hundreds or even thousands of species. And that would only be a start, since one would then need to consider which species are crucial to supporting those used directly: the bacteria, fungi, and invertebrates that help make soil fertile and break down wastes and organic matter; the insects, bats, and birds that pollinate flowers; and the grasses, herbs, and trees that hold soil in place, regulate the water cycle, and supply food for animals. The clear message of this exercise is that no one knows which combinations of species—or even approximately how many—are required to sustain human life.

Rather than selecting species directly, one might try another approach: Listing the ecosystem services needed by a lunar colony and then guessing at the types and numbers of species required to perform each. Yet determining which species are critical to the functioning of a particular ecosystem service is no simple task. Let us take soil fertility as an example. Soil organisms are crucial to the chemical conversion and physical transfer of essential nutrients to higher plants. But the abundance of soil organisms is absolutely staggering. Under a square yard of pasture in Denmark, for instance, the soil is inhabited by roughly 50,000 small earthworms and their relatives, 50,000 insects and mites, and nearly 12 million roundworms. And that tally is only the beginning. The number of soil animals is tiny compared to the number of soil microorganisms: a pinch of fertile soil may contain over 30,000 protozoa, 50,000 algae, 400,000 fungi, and billions of individual bacteria. Which must colonists bring to the moon to assure lush and continuing plant growth, soil renewal, waste disposal, and so on? Most of these soil-dwelling species have never been subjected to even cursory inspection: no human eye has ever blinked at them through a microscope, no human hand has ever typed out a name or description of them, and most human minds have never spent a moment reflecting on them. Yet the sobering fact is, as E. O. Wilson put it: They don't need us, but we need them.100

Clearly, the scientists who wrote this paper are pointing out that despite all the progress made in science, the vital role played by living things in ecological systems has been realized on recently. One thing is known for certain: Biodiversity makes the Earth an environment where all the conditions necessary for human beings are met. Obviously, the millions of species that act constantly on our behalf could not have come into being spontaneously or through series of coincidences; they were created and placed at our service by our Lord, the infinitely bountiful.

This chapter shall examine the outlines of a very small part of the blessings bestowed on us by the richness of species; and in this way, answer to some extent the question of why there exists such magnificent diversity on Earth.