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It’s Alive! Or Is It?

ff the coast of Western Australia, in ancient rock buried 3 miles below the ocean floor,lie what some scientists claim are the small-est living organisms ever discovered. These minus-cule life forms are known as nanobes because they are so tiny that they are measured in billionths of meters, or nanometers. But while some scientists are hailing this finding as an important discovery,

others argue that nanobes are not living organisms and could not possibly be.

The Australian researchers who recently discov-ered the nanobes say that the tiny organisms carry hereditary material, known as DNA, just as other liv-ing organisms do. These scientists also report that,like other forms of life, nanobes grow. In fact, nanobes grow so quickly that within weeks they go from

The Nature of Science and the Characteristics of Life

J o a n M i r ó,C a r n i v a l o f H a r l e q u i n ,1924–25.

c h a p t e r

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being visible only with the world’s most pow-erful microscopes to being visible to the naked eye as expanding colonies of threadlike mats.Skeptics, however, contend that nanobes are much too small to be alive, too small to contain the materials and machinery basic to life.

Any schoolchild can dis-tinguish between an inani-mate stone and the living being who skips it across a pond. How can it be that scientists cannot agree on whether something is alive or not?

What is life? Deceptively simple, this question is in many ways one of the most profound. It underlies medical controver-sies ranging from abortion and when life begins to the right to die and when life ends.It reaches deep into the sciences as we seek to understand when life on our planet first took hold and whether life has ever existed on other planets.

Scientists and philosophers alike have found that life defies easy, airtight defini-tion. What really does distinguish life from nonlife?

Tempest in a Teapot

Is this nanobe the smallest living organism ever discovered? Or is it not alive at all?

B iology is the scientific study of life. The main

goal of biology is to improve our understanding

of living organisms, from microscopic bacteria to giant redwood trees to human beings. In this chapter we begin with an exploration of science and how sci-entists ask and answer questions about living organ-isms. Then we move on to the most fundamental of bi-ological questions: What is life? We will see that all living things, diverse though they are, share character-istics that unify them, and that all living organisms are part of a greater biological hierarchy of life.

Asking Questions, Testing Answers: The Work of Science

Science is a method of inquiry, a rational way of dis-covering truths about the natural world. This powerful way of understanding nature holds a central place in modern society. For scientists and nonscientists alike, understanding how nature works can be exciting and fulfilling. In addition, applications of scientific knowl-edge influence all aspects of modern life. Every time we turn on a light, fly in an airplane, enjoy a vase of hot-house flowers, take medicine, or work at a computer, we are enjoying the benefits of science.

Yet few of us have a good picture of how science works, how it generates knowledge, and what its pow-ers and limits are. This lack of understanding is unfor-tunate for several reasons. First, an understanding of sci-ence can be personally rewarding. It can add to our appreciation of day-to-day events, leading to a sense of awe about how nature works.

A second reason is that science plays an increasingly important role in decisions made by society as a whole, as well as in personal decisions made by individuals. As a society, we must evaluate the discoveries made by sci-entists when making decisions about issues such as glob-al warming, the control of pollution, and even whether teachers in our public schools can provide their students with the most current forms of scientific knowledge. As individuals, we must also evaluate what scientists tell us in order to make decisions about such things as whether we will eat genetically engineered foods or treat our bodies using new drugs or medical procedures. To make good decisions on these and many other issues, everyone—not just scientists—benefits by understand-ing how the scientific process works.

In the sections that follow we first describe, in a gen-eral way, the methods scientists use to answer questions and learn about the natural world. Then we give an example of how one scientist answered a question. Scientists follow well-defined steps

to search for answers

The natural world is extremely complex. To deal with this complexity, scientists attempt to explain the nat-ural world by developing a simplified concept, or “model,” of how some part of nature works. No scien-tist attempts to study every conceivable thing that could influence the aspects of the natural world that interest him or her. Such a task would be impossible. Instead, scientists must master the “art” of simplifying nature in ways that can reveal exciting and important informa-tion.

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To construct such a simplified model of nature, scientists typically begin by observing, describing, and asking questions about the nat-ural world (Figure 1.1). In many ways, this beginning can be the most important step of a scientific study. How closely a scientist’s model of nature matches reality can hinge on the qual-ity of his or her initial observations.

The next step in the scientific process is to come up with a possible explanation—known as a hypothesis—of the phenomenon being studied. The hypothesis must have logical con-sequences that can be proved true or false. That is, the hypothesis must lead to a prediction that can be tested rigorously. If the results of the test match the prediction, the hypothesis is sup-ported, but not proved true. Proving a hypo-thesis true is not possible, because it always might fail if subjected to a different test. If the test does not uphold the prediction, the hypo-thesis must be rejected or changed. This last point is central to understanding how progress is made in science: Hypotheses are constantly being tested; the good ones are kept, the bad ones rejected. In this way, science can correct itself. Scientists develop a hypothesis, test its predictions by performing experiments, then change or discard the hypothesis if the predic-tions are not supported by the results of the tests. Togeth-er these steps are called the scientific method.

An experiment with honeysuckle demonstrates the scientific method

Dr. Katherine Larson, a botanist at the University of Cen-tral Arkansas, was interested in two species of vines: a species native to the United States, called coral honey-suckle, and a species from Asia, the Japanese honey-suckle (Figure 1.2). The Japanese honeysuckle has gor-geous flowers and was originally brought to the southeastern United States as a cultivated plant. But now it is considered a pest species. It has escaped from cul-tivation and is spreading so quickly that scientists are concerned it will drive native plant species to extinction.

Most vines must find supports to grow on (such as trees, shrubs, or fence posts) in order to survive. Dr. Lar-son wanted to understand why the Japanese honey-suckle was able to grow so well in the wild, even in areas with few supports. As she observed the 2 species in the wild, Dr. Larson noticed that Japanese honeysuckle

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Figure 1.2 A Scientist and Her Experimental Subjects

Dr. Katherine Larson’s experiments with honeysuckles are shedding

light on why one species of honeysuckle, introduced from Asia, is able

to spread more quickly than the honeysuckle species that is native to

its environment. The stem with red flowers is the native species; the

white-flowered stem is the pest species.

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spread rapidly across the ground, whereas the native honeysuckle tended to spread less quickly. Based on her observation, Dr. Larson came up with a possible expla-nation, or hypothesis. She hypothesized that the Japan-ese honeysuckle was more successful than the native species because it was better at locating new supports, especially supports that were far from where the vine was growing.

Dr. Larson’s hypothesis had logical predictions that could be tested: (1) that Japanese honeysuckle would grow across areas without supports more rapidly than the native coral honeysuckle would, and (2) that Japan-ese honeysuckle would find distant supports more often than coral honeysuckle would. In order to test her hypo-thesis and its predictions, Dr. Larson designed an exper-iment—a controlled, repeated manipulation of nature. In her experiment, she grew plants from each of the two honeysuckle species in a garden in which supports were placed both close to and far away from the plants.

Though still in progress, this experiment has already shown that Japanese honeysuckle does spread more rapidly across areas without supports than the native species does. Results from this experiment also suggest that Japanese honeysuckle is more effective at locating distant supports than the native species. Thus, the results

support both of Dr. Larson’s predictions, and her hypo-thesis.

In addition, Dr. Larson’s research has led to some new and unexpected findings. While conducting the honey-suckle experiment, she noticed differences in the details of how the plants grew. She knew that most plants rotate slowly about a central axis as they grow (Figure 1.3), and that vines show a pronounced version of this behavior. Dr. Larson observed that Japanese honeysuckle rotated differently than the native species. The way Japanese honeysuckle rotated as it grew along the ground allowed it to form roots more often and to spread more rapidly than the native species. Plants obtain nutrients and water through their roots. Thus, having the ability to form roots more often may allow the Japanese honeysuckle to survive in areas where the native species cannot.

To summarize, Dr. Larson conducted an experiment to test her hypothesis that the Japanese honeysuckle is outcompeting the native species because it spreads more rapidly and finds distant supports more easily. So far, the results of the experiment support her hypo-thesis. In addition, Dr. Larson made new observations about the details of plant growth that helped explain the results of the experiment. In this way Dr. Larson’s work illustrates an important point about how the sci-entific method works in practice: Chance observations and new discoveries often take the scientist in unex-pected directions, and that is part of what makes sci-ence so exciting.

Like all scientific studies, Dr. Larson’s work raises as many questions as it answers. What else might be con-tributing to the success of Japanese honeysuckle? Are there insects in its native environment in Asia that attack the honeysuckle to keep it from growing so heartily and spreading so quickly? Is an absence of such enemies in the United States helping the Japanese honeysuckle thrive in its new environment? Clearly, Dr. Larson’s studies are just the beginning in helping scientists to understand why these plants have been able to invade so successfully.

We have discussed the methods biologists use to study the living world. But what exactly is the living world? How do biologists define life?

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Figure 1.3Doing the Twist

This time-lapse photograph shows the position of a single

growing tip of a honeysuckle vine as it rotates on a central

axis. The way Japanese honeysuckle rotates may explain why

it is more successful than native honeysuckle.

from the highest mountaintop to the deepest regions of the sea, life is everywhere. How can all the world ’s liv-ing creatures, from whales to bacteria, fit into a single definition of life? In fact, the great diversity of body forms, habits, and sizes of organisms makes a simple,single-sentence definition of life impossible. But despite this diversity, all living organisms are thought to be descendants of a single common ancestor that arose bil-lions of years ago (see the box on page 000). For this rea-son, certain characteristics unify all forms of life. Biolo-gists define life by this set of shared characteristics (Table 1.1), which we describe in the sections that follow.

Living organisms are built of cells

The first organisms were single cells that existed billions of years ago, and the simplest of organisms still are made up of just a single cell. The cell remains the smallest and most basic unit of life. Enclosed by a membrane, cells organism.

Cells can be viewed as building blocks. A sustaining building block. lular at its most basic level a collection of cells (Figure 1.4).

Living organisms reproduce themselves using the hereditary material DNA

be discussed in detail in Unit 3.)eventually grow up to be adult humans, like those that produced them.

Whether organisms produce seeds, lay eggs, or just split in two, they all reproduce using a molecule known as DNA (deoxyribonucleic acid ). DNA is the hereditary ,or genetic, material that carries information from par-ents to offspring. We will discuss DNA in detail in Unit 3. Briefly , for our purposes here, the DNA molecule func-tions as a blueprint for building an organism. It is shaped like a double helix —imagine a ladder that is twisted along its length.

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The intestinal cells shown here are just one of many different kinds of cells in this monkey.

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Figure 1.4The Basic Building Block of Life: The Cell

Like all organisms, this Sykes ’ monkey is composed of cells.

Bacterium

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The DNA molecule (Figure 1.5) contains a wealth of information—all the information necessary for an organ-ism to create more cells like itself or to grow from a fer-tilized egg into a complex multicellular organism that will eventually produce offspring like itself. DNA is found in every cell in every living thing. Life, no mat-ter how simple or how complex, uses this inherited blue-print. Since all living organisms today reproduce using DNA, we can infer that our original ancestor also repro-duced using DNA.

Living organisms grow and develop

Using DNA as a blueprint, organisms grow and build themselves anew every generation. A human begins life as a simple, single cell that eventually grows and devel-ops inside its mother, emerging after 9 months as a liv-ing, breathing baby. This miraculous transformation is part of the process known as development(Figure 1.6). All organisms go through a process of development, whether they complete their growth as a single cell or continue to develop into something as complicated as a cactus or an octopus.

Living organisms capture energy

from their environment

To carry out their growth and development, and simply to persist, organisms need energy, which they must cap-ture from their environment. Organisms use a great vari-ety of methods to capture energy.

Plants are among the organisms that can capture the energy of sunlight through a chemical process known as photosynthesis, by which they produce sugars and starches. (We will discuss photosynthesis in detail in Chapter 8.) Some bacteria can also harness energy from chemical sources such as iron or ammonia through an entirely different chemical reaction. However, many organisms, such as animals, can capture energy only by consuming other organisms.

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Cell

Nucleus

DNA

This almond tree has produced offspring in the

form of almonds, DNA-contained seeds that will

eventually develop into new almond trees.

fpo

Figure 1.5The DNA Molecule: A Blueprint for Life

DNA is a hereditary blueprint found in the cells of every liv-

ing organism. DNA provides a set of instructions that an

individual organism can use to grow and develop, and

which it passes on to its offspring so that they, too, can

grow and develop.

Egg Caterpillar

Chrysalis Adult butterfly

Figure 1.6Growing Up: The Process of Development

All organisms develop. A monarch butterfly develops from

egg to caterpillar to chrysalis to flying adult.

Art sent back to studio

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Animals have many different ways of capturing ener-gy efficiently (Figure 1.7). Some insects, for example,have mouthparts that they use to suck the nutritive juices from plants. Cheetahs can run so quickly that they can chase and capture a fast-moving source of energy such as a gazelle.

Living organisms sense their environment and respond to it

In order to survive, different organisms must sense a wide range of different phenomena in their environ-ment, from danger to potential mates. Like humans,many organisms can smell, hear, taste, touch, and see their environments. But many organisms can see things humans cannot see, such as ultraviolet or infrared light.Others can hear sounds that humans cannot hear. Still others have senses that are entirely different from any human senses. Some bacteria, for example, can sense which direction is north and which direction is up or down using magnetic particles within their cells.

Organisms must not only gather information about their environment by sensing it, but must also respond appropriately to that information (Figure 1.8). Some responses don’t need to be learned; for example, a dog automatically pants when it is hot. But learning itself is an excellent example of sensing an environmental stim-ulus and responding to it. After touching a stinging nettle plant once, many organ-isms learn never to touch one again.Humans are particularly good at this kind of response because we have large brains relative to our body size. We can even learn very abstract lessons from our environment, such as how to read or

sing a song.

Living organisms show a high level of organization

Living organisms are complex, functioning beings com-posed of numerous essential components that are orga-nized in a very specific way. Human bodies, for exam-ple, have highly organized internal organs and tissues that allow the body to function properly. Organs or tis-sues in disarray, whether as a result of disease or acci-dent, can lead to illness or death. In the same way, the structure of a flower or a bacterial cell is highly orga-nized. Such organization is required for all organisms to function properly (Figure 1.9).

This green tree python has captured

a source of energy that it can ingest.

Figure 1.7Capturing Energy

While plants can capture energy through photosynthesis,animals, such as this green tree python, must get their ener-gy by eating other organisms.

Stinging nettle Figure 1.8Here Comes the Sun

All organisms must be able to sense and respond to stimuli in their environment. These Maryland sunflowers have all detected rays of sunshine and have turned toward their light and warmth.

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CHAPTER 1The Nature of Science and the Characteristics of Life

Living organisms evolve

In the developmental process, individual organisms change over short spans of time, developing from seeds into mature trees or from eggs into adult butterflies. Over longer time spans, whole groups of organisms change.A species is a group of organisms that can interbreed to produce fertile offspring (that is, offspring that themselves can reproduce) and that do not breed with other organ-isms outside that group. Mountain lions, monarch but-terflies, and Douglas fir trees are all distinct species of organisms.

The characteristics of a species can change over time —a process known as evolution . The pronghorn, for exam-ple, is the fastest-running creature in North America. Over time, these antelope became more fleet of foot because only the ones that could outrace their predators survived to reproduce. The offspring of these speedy survivors tend-ed to be speedy themselves because they shared much of their DNA with their parents.

In the struggle to survive and the contest to reproduce,characteristics of species —such as the average speed at which pronghorn can run —tend to change over time (Figure 1.10). Advantageous features that help an organ-ism survive or reproduce, such as the ability of a prong-horn to run quickly or the protective prickly hairs of a stinging nettle plant, are known as adaptations .

In evolution, not only can existing species change, but new species can come into being. For example, one species can split into two different species. Unit 4 will focus on all these aspects of evolution in detail.Levels of Biological Organization

Biologists organize the great array of living organisms,the many components that make up living organisms,and the environments they live in into a biological hier-archy (Figure 1.11).

At its lowest level, the biological hierarchy begins with molecules, such as the molecules of DNA that carry the blueprint for building an organism. Many such spe-cialized molecules are organized into a cell, the basic unit of life. Some organisms, such as bacteria, consist of only a single cell. Multicellular organisms can contain spe-cialized and coordinated collections of cells known as tissues , such as muscle tissues or nerve tissues, that per-

Brain

Muscle

Stomach

Lungs

Figure 1.9Staying Organized

Spatial organization—having each part in its proper place—is crucial to an organism’s func-tioning. The internal organs of a human being, such as the stomach, lungs, and brain, must be highly organized to function properly.

Teosinte

Domesticated corn

Figure 1.10Living Organisms Evolve

Over time, species of living organisms evolve. Domesticated corn plants, for example, have many large kernels, or seeds,on large cobs. These familiar corn plants evolved from the wild species known as teosinte, which has fewer, smaller seeds.

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UNIT 1Diversity of Life

Organ system (nervous system)

Community (the various fish species living

on the reef)

Biome (coral reefs)

Individual

(an Emperor angelfish)

Population

(the Emperor angelfish living on one coral reef)

Ecosystem (a tropical coral reef)

Species

(all populations of Emperor angelfish that can interbreed)

form particular, specialized functions in the body . Some-times these tissues are organized into organs , such as hearts or brains. Groups of organs can work together in organ systems , the way the stomach, liver, and intestines are all part of the digestive system. Groups of organ systems work together in the functioning of a single organism —an individual .

Each individual organism is a member of a larger group of similar organisms, known as a population —for exam-ple, a population of field mice in one field or a population of blueberry plants on a mountaintop. As we have already learned, all the populations of all similar organisms in the world that can successfully breed with one another form a species. For example, all the humans in the world form one species, known as Homo sapiens . A group of different species that live and interact in a particular area is known as a community —for example, the community of insect species living in a forest.

Communities plus the physical environments in which they are situated are known as ecosystems ; for example, a river ecosystem includes the river itself as well as the community of organisms living in it. At an even larger scale are the large regions of the world known as biomes . On land, biomes are defined by vegetation type,and in water, they are defined by the physical charac-teristics of the environment. The coral reef and the arc-tic tundra are two different kinds of biomes. Finally , each biome is part of the biosphere , which is defined as all the world ’s living organisms and the places where they live.Energy Flow through Biological Systems

Energy flows continually through living systems. Plants and other photosynthesizing organisms are called pro-ducers because they take energy from sunlight and pro-duce chemical energy in the form of sugars and starches.

That energy is then harvested by consumers , such as ani-mals and fungi. Consumers eat either plants or other organisms whose energy ultimately derives from plants.Decomposers obtain energy by decomposing, or break-ing down, dead organisms. As a result, energy flows almost entirely in one direction through the biosphere:from the sun to producers, which form the basis of the energy flow, and then to consumers and decomposers,which give off energy as heat (Figure 1.12). A diagram of energy flow through an ecosystem showing which species are eating which other species is known as a food web .s HIGHLIGHT

Life on the Edge: Viruses

Every winter millions of people are laid low by the influenza virus. If you come down with the flu, the symp-toms are all too familiar: You are achy. You cough and sneeze. The reason you ’re suffering is that an influenza virus is infecting your body ’s cells, reproducing through-out your nose, throat, and lungs.

The specialized cells of your immune system (see Chapter 32) fight back, attacking and destroying cells already infected by the virus and raising your temper-ature (hence your high fever) to prevent the virus from reproducing. But the microscopic flu virus can knock you out for days or weeks, replicating itself again and again at your body ’s expense while evading your body ’s defenses. The influenza virus also evolves rapidly over time, changing so quickly that defending against it is extremely difficult. A virus is thus a formidable enemy.In fact, the flu virus has been a deadly foe through-out human history. In 1918 the Spanish flu epidemic killed more than half a million people in the United States, 10 times the toll of U.S. soldiers killed in World War I. Worldwide, the flu epidemic of 1918 killed between 20 million and 40 million people in just half a year. But there is much more to viruses than those that cause influenza in humans. There are many different kinds of viruses that infect all the different forms of life.These powerful foes certainly seem alive, just like the many organisms they attack. Like living organisms,viruses reproduce, show a high level of organization,and evolve. Yet all viruses, including the influenza virus,lack some of the basic characteristics of life. For exam-

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The Biological Hierarchy

ecosystems, to biomes, and finally to the biosphere, which includes all living organisms and the places where they live.

1.3

ple, unlike living organisms, viruses are not made up of cells. A virus is simply a hereditary blueprint, a piece of genetic material wrapped in a coat of protein. Unlike cells or organisms made from cells, viruses lack the structures necessary, for example, to gather energy,reproduce, and do nearly all the things living organisms do. In order to reproduce, viruses must take over the cel-lular machinery of the hosts they invade.

Another unusual feature of viruses is that, unlike liv-ing organisms, the genetic material they pass from one generation to the next is not always DNA. Some viruses employ another molecule, known as RNA, or ribonu-cleic acid. (We will learn more about RNA in Unit 3.)So, are viruses inanimate or alive?

In fact, viruses raise many of the same questions as nanobes, the incredibly tiny organisms described at the start of this chapter. Like viruses, nanobes show some characteristics of living organisms. Nanobes appear to carry genetic material and to grow. But, like viruses,nanobes do not appear to share all the characteristics of living organisms. Some scientists say, for example, that nanobes are too small to be made up of cells.

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Sunlight

Producers (desert plants)

Decomposer (mold)

Heat

Consumers (kangaroo rat,rattlesnake, and burrowing owl)

Heat

Figure 1.12Energy Flow through an Ecosystem

Sunlight is captured by producers —in this case, desert plants. Energy then flows to con-sumers, such as the fruit-eating kangaroo rat, that eat those producers. Those consumers are then eaten by other consumers, such as the rattlesnake, which can then be eaten by still other consumers. Decomposers, such as the mold on the fruit, likewise get their energy either from plants or from organisms whose energy ultimately derives from plants. Decom-posers and consumers give off energy in the form of heat. Energy flows from the sun to producers and then to consumers and decomposers throughout this food web.

Much more remains to be learned about nanobes, but like the well-known viruses, they defy easy definition.Many scientists consider viruses to be nonliving. Other biologists place viruses in a gray zone between life and nonlife. However we choose to define such fascinating entities, viruses and nanobes both force us to stretch the limits of our definitions while making it clear just how diverse life on Earth can be.

SUMMARY

Asking Questions,T esting Answers:The W ork of Science

To answer questions about the natural world, scientists begin with observations of nature, formulate hypotheses from those observations, test those hypotheses, and then reject or modify them as necessary.

Scientists test their hypotheses by performing controlled,repeated manipulations of nature known as experiments.The Characteristics that All Living Organisms Share

s The great diversity of life on Earth is unified by a set of shared characteristics.

All living organisms are built of cells, reproduce using DNA, grow and develop, capture energy from their envi-ronment, sense and respond to their environment, show a high level of organization, and evolve.

Levels of Biological Organization

Living organisms are part of a biological hierarchy with levels from molecules through cells, tissues, organs, organ systems, individuals, populations, species, communities,ecosystems, and biomes to the biosphere.

Energy Flow through Biological Systems

Energy flows through biological systems from producers,such as plants, that create chemical energy in the form of sugars and starches from sunlight, to consumers, such as animals, that eat plants or other organisms whose energy ultimately derives from plants.

Highlight:Life on the Edge:Viruses

Viruses, which have some, but not all, of the characteris-tics of living organisms, illustrate how difficult it can be to define life precisely.

KEY TERMS

adaptation p. 00food web p. 00biome p. 00hypothesis p. 00biosphere p. 00individual p. 00cell p. 00multicellular p. 00community p. 00organ system p. 00consumer p. 00organ p. 00decomposer p. 00population p. 00development p. 00

producer p. 00DNA (deoxyribonucleic acid)p. 00science p. 00

ecosystem p. 00scientific method p. 00evolution p. 00species p. 00experiment p. 00

tissue p. 00

CHAPTER REVIEW

Self-Quiz

1.Which of the following is not an essential element of the scientific method?a.observations b.conjecture c.experiments d.hypotheses

2.After reading about Dr. Larson ’s research, another scien-tist said, “Japanese honeysuckle might also be doing well in the United States because it isn ’t being attacked by any of its natural enemies, such as insects, from Asia.” This statement is an example of a.an experiment.b.a hypothesis.c.a test.

d.a prediction.3.Which of the following are both universal characteristics of life?

a.the ability to grow and the ability to reproduce using DNA

b. the ability to reproduce using DNA and the ability to capture energy directly from the sun

c.the ability to move and the ability to sense the environ-ment

d.the ability to sense the environment and the ability to grow indefinitely 4.Which of the following is the basic unit of life?a.virus b.DNA c.cell

https://www.wendangku.net/doc/0b265372.html,anism

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5.Which of the following can reproduce without its own DNA?

a.human being

b.virus

c.single-celled organism

d.none of the above

6.Which of the following is a multicellular organism?

a.beetle

b.brain

c.bacterium

d.forest ecosystem Review Questions

1.What are the observations, hypotheses, and experiments in Dr. Larson’s honeysuckle work?

2.What are the elements of the biological hierarchy, and how are they arranged in their proper relationship with respect to one another, from smallest to largest?

3.How does energy flow through biological systems?

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W EST H ARTSVILLE, T ENNESSEE—Concerned citizens crowded the local elementary school gymnasi-um yesterday to hear arguments about whether “creation science”should be taught alongside evolu-tionary biology in this small town’s classrooms. In contrast to biolo-gists, creation scientists purport that species do not change over time and that all organisms are un-changeable and designed by a di-vine creator.

“Creation science is not a sci-

ence at all, but a set of religious be-

liefs,” said Dr. Naomi Latte, evolu-

tionary biologist at Tennessee State

College, speaking before the

school board. “It should not be

taught alongside evolutionary biol-

ogy.” Dr. Latte argued that faith

“has its place in the home, the

church, and in private schools, but

not in public schools,” where the

law requires a separation of church

and state.

Dr. Tim Garter, of the Creation

Science Foundation, countered that

creation science is a real science.

“Though people like Miss Latte

will tell you otherwise, creation

science is a legitimate field of

study, and we should not be cen-

sored by university biologists, so

many of whom are the worst kind

of atheists. Students have the right

to know the full range of scientific

ideas, however noxious those ideas

might be to some people.”

Creationism Fights for a Place alongside Evolution in the Classroom

CHAPTER 1The Nature of Science and the Characteristics of Life17