Concepts in Biology 10th ed - Enger, Ross (McGraw-Hill, 2002) WW.pdf - Biologia - koloidalnyy

Enger−Ross: Concepts in

Biology, Tenth Edition

I. Introduction

1. What Is Biology?

Companies, 2002

It is often helpful when learning new material to have the goals clearly stated before that material is presented. It is also helpful to have

some idea why the material will be relevant. This information can provide a framework for organization as well as serve as a guide to

identify the most important facts. The following table will help you identify the key topics of this chapter as well as the significance of

mastering those topics.

CHAPTER 1

Chapter Outline

1.1 The Significance of Biology

in Your Life

1.2 Science and the Scientific Method

Observation • Questioning and Exploration •

Constructing Hypotheses • Testing

Hypotheses • The Development of Theories

and Laws • Communication

1.3 Science, Nonscience,

and Pseudoscience

Fundamental Attitudes in Science • From

Discovery to Application • Science and

Nonscience • Pseudoscience • Limitations

of Science

1.4 The Science of Biology

Characteristics of Life • Levels of Organization •

The Significance of Biology • Consequences

of Not Understanding Biological Principles •

Future Directions in Biology

HOW SCIENCE WORKS 1.1: Edward Jenner

and the Control of Smallpox

Key Concepts

Applications

Understand the process of science as well as differentiate

between science and nonscience.

• Know if information is the result of scientific investigation.

• Explain when “scientific claims” are really scientific.

• Recognize that some claims are pseudoscientific and are designed

to mislead.

Understand that many advances in the quality of life are the

result of biological discoveries.

• Give examples of how biological discoveries have improved

your life.

• Recognize how science is relevant for you.

Differentiate between applied and theoretical science.

• Describe the kinds of problems biologists have to deal with now

and in the future.

Recognize that science has limitations.

• Give examples of problems caused by unwise use of biological

information.

• Identify questions that science is not able to answer.

Know the characteristics used to differentiate between living

and nonliving things.

• Correctly distinguish between living and nonliving things.

What Is Biology?

Enger−Ross: Concepts in

Biology, Tenth Edition

I. Introduction

1. What Is Biology?

Companies, 2002

Part 1 Introduction

1.1 The Significance of Biology

in Your Life

Many college students question the need for science courses

such as biology in their curriculum, especially when their

course of study is not science related. However, it is becom-

ing increasingly important that all citizens be able to recog-

nize the power and limitations of science, understand how

scientists think, and appreciate how the actions of societies

change the world in which we and other organisms live.

Consider how your future will be influenced by how the fol-

lowing questions are ultimately answered:

Does electromagnetic radiation from electric power

lines, computer monitors, cell phones, or microwave

ovens affect living things?

Is DNA testing reliable enough to be admitted as evi-

dence in court cases?

Is there a pill that can be used to control a person’s

weight?

Can physicians and scientists manipulate our genes in

order to control certain disease conditions we have

inherited?

Will the thinning of the ozone layer of the upper atmo-

sphere result in increased incidence of skin cancer?

Will a vaccine for AIDS be developed in the next

10 years?

Will new, inexpensive, socially acceptable methods of

birth control be developed that can slow world

population growth?

Are human activities really causing the world to get

warmer?

How does extinction of a species change the ecological

situation where it once lived?

As an informed citizen in a democracy, you can have a

great deal to say about how these problems are analyzed and

what actions provide appropriate solutions. In a democracy

it is assumed that the public has gathered enough informa-

tion to make intelligent decisions (figure 1.1). This is why an

understanding of the nature of science and fundamental bio-

logical concepts is so important for any person, regardless of

his or her vocation. Concepts in Biology was written with

this philosophy in mind. The concepts covered in this book

are core concepts selected to help you become more aware of

how biology influences nearly every aspect of your life.

Most of the important questions of today can be con-

sidered from philosophical, social, and scientific stand-

points. None of these approaches individually presents a

solution to most problems. For example, it is a fact that the

human population of the world is growing very rapidly.

Philosophically, we may all agree that the rate of population

growth should be slowed. Science can provide information

about why populations grow and which actions will be the

most effective in slowing population growth. Science can

Figure 1.1

Biology in Everyday Life

These news headlines reflect a few of the biologically based issues

that face us every day. Although articles such as these seldom

propose solutions, they do inform the general public so that

people can begin to explore possibilities and make intelligent

decisions leading to solutions.

also develop methods of conception control that would limit

a person’s ability to reproduce. Killing infants and forced

sterilization are both methods that have been tried in some

parts of the world within the past century. However, most

would contend that these “solutions” are philosophically or

socially unacceptable. Science can provide information

about the reproductive process and how it can be con-

trolled, but society must answer the more fundamental

social and philosophical questions about reproductive rights

and the morality of controls. It is important to recognize

that science has a role to play but that it does not have the

answers to all our problems.

1.2 Science and the Scientific Method

You already know that biology is a scientific discipline and

that it has something to do with living things such as micro-

organisms, plants, and animals. Most textbooks define biol-

ogy as the science that deals with life. This basic definition

seems clear until you begin to think about what the words

science and life mean.

Enger−Ross: Concepts in

Biology, Tenth Edition

I. Introduction

1. What Is Biology?

Companies, 2002

Chapter 1 What Is Biology?

The word science is a noun derived from a Latin term

( scientia ) meaning knowledge or knowing. Humans have

accumulated a vast amount of “knowledge” using a variety

of methods, some by scientific methods and some by other

methods.

Science is distinguished from other fields of study by

how knowledge is acquired, rather than by the act of accumu-

lating facts. Science is actually a process used to solve prob-

lems or develop an understanding of natural events that

involves testing possible answers. The process has become

known as the scientific method. The scientific method is a way

of gaining information (facts) about the world by forming

possible solutions to questions followed by rigorous testing to

determine if the proposed solutions are valid ( valid = mean-

ingful, convincing, sound, satisfactory, confirmed by others).

When using the scientific method, scientists make sev-

eral fundamental assumptions. There is a presumption that:

ing of days that occurs in the autumn. Experiments have

shown that artificially shortening the length of days in a

greenhouse will cause the trees to drop their leaves even

though there is no change in temperature. Knowing that a

cause-and-effect relationship exists enables us to make pre-

dictions about what will happen should that same set of cir-

cumstances occur in the future.

This approach can be used by scientists to solve partic-

ular practical problems, such as how to improve milk pro-

duction in cows or to advance understanding of important

concepts such as evolution that may have little immediate

practical value. Yet an understanding of the process of evo-

lution is important in understanding genetic engineering, the

causes of extinction, or human physiology—all of which

have practical applications. The scientific method requires a

systematic search for information and a continual checking

and rechecking to see if previous ideas are still supported by

new information. If the new evidence is not supportive, sci-

entists discard or change their original ideas. Scientific ideas

undergo constant reevaluation, criticism, and modification.

The scientific method involves several important identifi-

able components, including careful observation, the construc-

tion and testing of hypotheses, an openness to new

information and ideas, and a willingness to submit one’s ideas

to the scrutiny of others. However, it is not an inflexible series

of steps that must be followed in a specific order. Figure 1.2

shows how these steps may be linked and table 1.1 gives an

example of how scientific investigation proceeds from an ini-

tial question to the development of theories and laws.

1. There are specific causes for events observed in the

natural world,

2. That the causes can be identified,

3. That there are general rules or patterns that can be

used to describe what happens in nature,

4. That an event that occurs repeatedly probably has the

same cause,

5. That what one person perceives can be perceived by

others, and

6. That the same fundamental rules of nature apply

regardless of where and when they occur.

For example, we have all observed lightning associated

with thunderstorms. According to the assumptions that have

just been stated, we should expect that there is an explana-

tion that would explain all cases of lightning regardless of

where or when they occur and that all people could make

the same observations. We know from scientific observations

and experiments that lightning is caused by a difference in

electrical charge, that the behavior of lightning follows gen-

eral rules that are the same as that seen with static electricity,

and that all lightning that has been measured has the same

cause wherever and whenever it occurred.

Scientists are involved in distinguishing between situa-

tions that are merely correlated (happen together) and those

that are correlated and show cause-and-effect relationships.

When an event occurs as a direct result of a previous event, a

cause-and-effect relationship exists. Many events are corre-

lated, but not all correlations show a cause-and-effect rela-

tionship. For example, lightning and thunder are correlated

and have a cause-and-effect relationship. However, the rela-

tionship between autumn and trees dropping their leaves is

more difficult to sort out. Because autumn brings colder tem-

peratures many people assume that the cold temperature is

the cause of the leaves turning color and falling. The two

events are correlated. However there is no cause-and-effect

relationship. The cause of the change in trees is the shorten-

Observation

Scientific inquiry often begins with an observation that an

event has occurred repeatedly. An observation occurs when

we use our senses (smell, sight, hearing, taste, touch) or an

extension of our senses (microscope, tape recorder, X-ray

machine, thermometer) to record an event. Observation is

more than a casual awareness. You may hear a sound or see

an image without really observing it. Do you know what

music was being played in the shopping mall? You certainly

heard it but if you are unable to tell someone else what it

was, you didn’t “observe” it. If you had prepared yourself to

observe the music being played, you would be able to iden-

tify it. When scientists talk about their observations, they are

referring to careful, thoughtful recognition of an event—not

just casual notice. Scientists train themselves to improve their

observational skills since careful observation is important in

all parts of the scientific method.

The information gained by direct observation of the

event is called empirical evidence ( empiric = based on experi-

ence; from the Greek empirikos = experience). Empirical evi-

dence is capable of being verified or disproved by further

observation. If the event occurs only once or cannot be

repeated in an artificial situation, it is impossible to use the

Enger−Ross: Concepts in

Biology, Tenth Edition

I. Introduction

1. What Is Biology?

Companies, 2002

Part 1 Introduction

Communicate

with other

scientists

Fit with current

scientific theo-

ries and laws

Make

observation

Ask

questions

Formulate

hypothesis

Test

hypothesis

Develop new

scientific

theory or law

Revise

hypothesis

Figure 1.2

The Scientific Method

The scientific method is a way of thinking that involves making hypotheses about observations and testing the validity of the hypotheses.

When hypotheses are disproved, they can be revised and tested in their new form. Throughout the scientific process, people communicate

about their ideas. Theories and laws develop as a result of people recognizing broad areas of agreement about how the world works. Current

laws and theories help people formulate their approaches to scientific questions.

scientific method to gain further information about the event

and explain it.

more information. Perhaps the question has already been

answered by someone else or several possible answers have

already been rejected. Knowing what others have already

done allows one to save time and energy. This process usu-

ally involves reading appropriate science publications,

exploring information on the Internet, or contacting fellow

scientists interested in the same field of study. Even if the

particular question has not been answered already, scientific

literature and other scientists can provide insights that may

lead toward a solution. After exploring the appropriate liter-

ature, a decision is made about whether to continue to

explore the question. If the scientist is still intrigued by the

question, a formal hypothesis is constructed and the process

of inquiry continues at a different level.

Questioning and Exploration

As scientists gain more empirical evidence about an event

they begin to develop questions about it. How does this hap-

pen? What causes it to occur? When will it take place again?

Can I control the event to my benefit? The formation of the

questions is not as simple as it might seem because the way

the questions are asked will determine how you go about

answering them. A question that is too broad or too com-

plex may be impossible to answer; therefore a great deal of

effort is put into asking the question in the right way. In

some situations, this can be the most time-consuming part of

the scientific method; asking the right question is critical to

how you look for answers.

Let’s say, for example, that you observed a cat catch, kill,

and eat a mouse. You could ask several kinds of questions:

Constructing Hypotheses

A hypothesis is a statement that provides a possible answer

to a question or an explanation for an observation that can

be tested. A good hypothesis must be logical, account for all

the relevant information currently available, allow one to

predict future events relating to the question being asked, and

be testable. Furthermore, if one has the choice of several

competing hypotheses one should use the simplest hypothesis

with the fewest assumptions. Just as deciding which questions

to ask is often difficult, the formation of a hypothesis requires

much critical thought and mental exploration. If the hypothe-

sis does not account for all the observed facts in the situation,

doubt will be cast on the work and may eventually cast doubt

on the validity of the scientist’s work. If a hypothesis is not

1a. Does the cat like the taste of the mouse?

1b. If given a choice between mice and canned cat food,

which would a cat choose?

2a. What motivates a cat to hunt?

2b. Do cats hunt only when they are hungry?

Obviously, 1b and 2b are much easier to answer than

1a and 2a even though the two sets of questions are attempt-

ing to obtain similar information.

Once a decision has been made about what question to

ask, scientists explore other sources of knowledge to gain

Enger−Ross: Concepts in

Biology, Tenth Edition

I. Introduction

1. What Is Biology?

Companies, 2002

Chapter 1 What Is Biology?

Table 1.1

THE NATURE OF THE SCIENTIFIC METHOD

Component of

Science Process

Description of Process

Example of the Process in Action

Observation

Recognize something has happened and that it

occurs repeatedly.

(Empirical evidence is gained from experience or

observation.)

Doctors observe that many of their patients, who are suffering from tubercu-

losis, fail to be cured by the use of the medicines (antibiotics) traditionally

used to treat the disease.

Question

formulation

Ask questions about the observation, evaluate

the questions, and keep the ones that will be

answerable.

Have the drug companies modified the antibiotics?

Are the patients failing to take the antibiotics as prescribed?

Has the bacterium that causes tuberculosis changed?

Exploration of

alternative

resources

Go to the library to obtain information about this

observation.

Talk to others who are interested in the same

problem.

Visit other researchers or communicate via letter,

fax, or computer to help determine if your ques-

tion is a good one or if others have already

explored the topic.

Read medical journals.

Contact the Centers for Disease Control and Prevention.

Consult experts in tuberculosis.

Attend medical conventions.

Contact drug companies and ask if their antibiotic formulation has been

changed.

Hypothesis

formation

Pose a possible answer to your question.

Be sure that it is testable and that it accounts for

all the known information.

Recognize that your hypothesis may be wrong.

Tuberculosis patients who fail to be cured by standard antibiotics have

tuberculosis caused by antibiotic resistant populations of the bacterium

Mycobacterium tuberculosis.

Test hypothesis

(Experimentation)

Set up an experiment that will allow you to test

your hypothesis using a control group and an

experimental group.

Be sure to collect and analyze the data

carefully.

Set up an experiment in which samples of tuberculosis bacteria are collected

from two groups of patients; those who are responding to antibiotic ther-

apy but still have bacteria and those who are not responding to antibiotic

therapy.

Grow the bacteria in the lab and subject them to the antibiotics normally

used.

Use a large number of samples.

The bacteria from the patients who are responding positively to the antibi-

otics are the control. The samples from those that are not responding con-

stitute the experimental group.

Experiments consistently show those patients who are not recovering have

strains of bacteria that are resistant to the antibiotic being used.

Agreement with

existing scientific

laws and theories

New laws or

theories are

constructed

If your findings are seen to fit with other major

blocks of information that tie together many

different kinds of scientific information, they will

be recognized by the scientific community as

being consistent with current scientific laws and

theories.

In rare instances, a new theory or law may develop

as a result of research.

Your results are consistent with the following laws and theories:

Mendel’s laws of heredity state that characteristics are passed from parent

to offspring during reproduction.

The theory of natural selection predicts that when populations of organisms

like Mycobacterium tuberculosis are subjected to something that kills many

individuals in the population, those individuals that survive and reproduce

will pass on the characteristics that allowed them to survive to the next

generation and that the next generation will have a higher incidence of the

characteristics.

The discovery of the structure of DNA and subsequent research has led to

the development of a major new theory and has led to a much more clear

understanding of how changes (mutations) occur to genes.

Conclusion and

communication

You arrive at a conclusion. Throughout the

process, communicate with other scientists both

by informal conversation and formal publications.

You conclude that the antibiotics are ineffective because the bacteria are resis-

tant to the antibiotics. This could be because some of the individual bacteria

contained altered DNA (mutation) that allowed them to survive in the pres-

ence of the antibiotic. They survived and reproduced passing their resistance

to their offspring and building a population of antibiotic resistant tuber-

culosis bacteria.

A scientific article is written describing the experiment and your

conclusions.

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