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Science 101: Ecology
Life On a Small Planet
Ecologist Edward O. Wilson has said humanity is now "passing through a bottleneck," a period of great challenge. There are now so many humans, using so many of the Earth's resources, that humans have the power to alter the very life support systems of our planet. How will a growing population that will reach 9 billion souls live and eat without destroying the living planet?
The science of ecology essentially is the basic quest to determine how the natural world works. Ecology is a relatively new science. It is about understanding how the parts fit together: predators and parasites, plants and soil, geography and genetics, insects and bacteria. It addresses key questions: Why are there so many species in the tropics? How do desert animals manage water resources? It also addresses applied questions: What will happen to life on Earth and the cycles that support it as climate-warming gases build up in our atmosphere? How is life on Earth affected by habitat loss or damage to the ozone layer? These are just a few of the issues studied by ecologists. The skills needed to survive this time of challenge must include a sound understanding of what makes the planet live in the first place.
Land of Opportunity
In the nineteenth century, thewild lands and wildlife of the United States seemed boundless to recently arrived Europeans. Railroads bored through the center of the country. Settlers plowed the prairie under for corn, and fenced off wild land for farms and ranches. The race to draw riches from the new land—furs, gold, timber, beef—rose to a fever pitch.
Buffalo were slaughtered so fast that where tens of millions had blackened the prairies in 1850, by 1884 their numbers had been reduced to fewer than one thousand. Egrets were hunted nearly to extinction as well, their elegant feathers prized for ladies' hats. Beaver, too, were hunted to a tiny fraction of their former population, their fur made into top hats. Ancient redwoods were chopped down for lumber to build gold-rush boomtowns.
Forest was cleared, towns and cities constructed. People, plants, and animals that had lived on the land for thousands of years were replaced by the newcomers.
In the middle of this race for riches, another kind of voice emerged. At the same time that buffalo and egrets were brought to the brink of extinction, some Americans began to write and speak of the majesty of nature. The land and its wild creatures, they argued, should be cherished as more than just a source of raw materials for building houses and fortunes.
"Everybody needs beauty as well as bread, places to play in and pray in, where nature may heal and give strength to body and soul," wrote Scottish-born naturalist John Muir. Some saw that nature was under threat from the great changes happening as the country grew and expanded westward. Preserving and protecting nature was necessary, the new argument went, not only for conserving resources, but for the very health of the human spirit.
Of course, the view that Earth is a living thing to be nurtured and honored by man was common among Native Americans. Iroquois law in the nineteenth century, for instance, stated: "In our every deliberation, we must consider the impact of our decisions on the next seven generations." But for European Americans, the idea seemed new.
A New Science
While naturalist writers wrote of the beauty and wonders of nature, others began to create a new, scientific understanding of the landscape. Earlier students of Earth and its life had focused on the separate pieces they saw—flowers, microbes, field mice, weather. But by the late nineteenth century, scientists were looking to understand how natural systems function over time and space, what makes species succeed or fail, and how living and nonliving worlds connect.
Scientists began looking at nature as a series of interconnected systems, small units and large ones, all part of the bigger picture. They began to research the dynamics of nature's chemical, physical, and biological cycles, and to recognize that the success of all creatures depends on their interactions with one another, with other species, and with the nonliving components of their home environments.
This new science was dubbed "ecology," ology meaning "study," and eco from the Greek word oikos, meaning "the place where we live, our home."
It is easy for humans to feel that we are the central and most important species on Earth. After all, it is human faces we see in the mirror each day, humans we love, human communities we inhabit.
Looking at species on Earth from a numerical point of view, however, a completely different picture emerges. Defined by the number of species on Earth, humans, along with all other mammals, are rare indeed. Scientists have described approximately 1.4 million species of living organisms. This number includes all manner of life, ranging from bacteria to oak trees to lions. Of these, almost two-thirds are insects; another quarter million or so are plants. A mere 4,000 known species are mammals.
More than 750,000 of the 1.4 million known species on our planet are insects. The insects, which include beetles, butterflies, ants, and termites, far outnumber their vertebrate cousins.
The most common type of insect is the family known as coleoptera, or "sheathed wing" insects—the beetles. There are nearly 300,000 known species of beetle, more than all noninsect animal species combined.
A story is told about J. B. S. Haldane, a well-known British biologist and evolutionary thinker. Once, Haldane was asked what a person could conclude as to the nature of the Creator from a study of his creation. Haldane is said to have answered, "an inordinate fondness for beetles."
Insects play many important roles. Bees and butterflies are famous for helping plant life to reproduce by pollinating flowers. Flies and their larvae help to break down dead plant and animal matter so that . . .Science 101: Ecology. Copyright © by Jennifer Freeman. Reprinted by permission of HarperCollins Publishers, Inc. All rights reserved. Available now wherever books are sold.