Prentice hall Biology Worksheets

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Chapter 1 The Science of Biology

Summary

1?1 What Is Science?

Science is an organized way of using evidence to learn about the natural world. Scientific thinking usually begins with observation, which is the process of gathering information about events or processes in a careful, orderly way. The information gathered from observations is called data. Quantitative data are expressed as numbers, obtained by counting or measuring. Qualitative data are descriptive and involve characteristics that can't usually be counted. Scientists use data to make inferences. An inference is a logical interpretation based on prior knowledge or experience.

After making first observations, a researcher will propose one or more hypotheses. A hypothesis is a proposed scientific explanation for a set of observations. Scientists generate hypotheses using prior knowledge, logical inference, and informed, creative imagination. Scientific hypotheses must be proposed in a way that enables them to be tested. Hypotheses are tested by performing controlled experiments. The conclusions researchers draw from experiments or data must be valid. To be valid, a conclusion must be based on logical interpretation of reliable data.

1?2 How Scientists Work

Conducting a scientific investigation involves a series of steps. The first step is asking a question. The second step involves forming a hypothesis. The third step in conducting a scientific investigation is setting up a controlled experiment. A hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged. This type of experiment is called a controlled experiment. The variable that is deliberately changed is called the manipulated variable. The variable that is observed and that changes in response

to the manipulated variable is called the responding variable.

The fourth step in conducting a scientific investigation is recording and analyzing results. The fifth step is drawing a conclusion. A key assumption in science is that experimental results can be reproduced.

As evidence builds up, a particular hypothesis may become so well supported that scientists consider it a theory. In science, a theory is a well-tested explanation that unifies a broad range of observations.

1?3 Studying Life

Although living things vary greatly, all living things share eight characteristics:

1. Living things are made up of units called cells. Cells are the smallest units of an organism that can be considered alive.

2. Living things reproduce. In sexual reproduction, cells from two different parents unite to produce the first cell of the new organism. In asexual reproduction, a single cell divides in half to form two new organisms.

3. Living things are based on a universal genetic code. The directions for inheritance are carried by a molecule called DNA.

4. Living things grow and develop. Multicellular organisms typically go through a process called development. As cells divide, they change in shape and structure in a process called differentiation.

5. Living things obtain and use materials and energy. The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes is called metabolism.

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6. Living things respond to their environment. A stimulus is a signal to which an organism responds.

7. Living things maintain a stable internal environment. The process by which they do this is called homeostasis.

8. Taken as a group, living things change over time. Change over time in living things is called evolution.

All biological sciences are tied together by overriding themes, or "big ideas." You will see that these big ideas overlap and connect with one another. The 10 big ideas in biology are as follows:

1. Evolution: This is the main unifying theme of biology because this theory tells us that all forms of life on Earth are related to a common ancestor and therefore explains the unity and diversity of life.

2. Science as a Way of Knowing: Science is not a list of facts, but a method of study that explains the natural world in terms of forces and events.

3. Matter and Energy: Life's most basic requirements are matter, which serves as nutrients, and energy, which fuels the processes of life.

4. Interdependence in Nature: Within the biosphere, organisms are linked to one another and to the land, water, and air around them.

5. Cellular Basis of Life: A cell is the smallest unit capable of all life functions. The basic structure of the cell is the same in all organisms.

6. Information and Heredity: Life's processes are directed by information carried in a genetic code.

7. Unity and Diversity of Life: All organisms are composed of a common set of carbon-based molecules, use proteins, and store a common genetic code.

8. Structure and Function: Each major group of organisms has its own body parts to serve specific functions.

9. Homeostasis: All organisms must maintain a stable internal environment in order to function properly.

10. Science, Technology, and Society: People must truly understand what science is and how it works in order to make educated decisions about our world and how our activities impact it.

Biology is divided into different fields of study. Some fields focus on the study of living systems at different levels. These levels include, from smallest to largest: molecules, cells, groups of cells, organisms, populations, communities, ecosystems, and the biosphere.

1?4 Tools and Procedures

Most scientists use the metric system when collecting data. The metric system is a decimal system of measurement whose units are based on certain physical standards and are scaled on multiples of 10.

A microscope is a device that produces magnified images of structures that are too small to see with the unaided eye. Light microscopes produce magnified images by focusing visible light rays. Compound light microscopes allow light to pass through the specimen and use two lenses to form an image. Electron microscopes use beams of electrons to produce magnified images. Biologists use two main types: the transmission electron microscope (TEM) and the scanning electron microscope (SEM).

Whenever you work in your biology laboratory, it's important for you to follow safe practices. The single most important rule for your safety is simple: Always follow your teacher's instructions and the textbook directions exactly. Because you may be in contact with organisms you cannot see, it is essential that you wash your hands thoroughly after every scientific activity.

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Name______________________________ Class __________________ Date ______________

Chapter 1 The Science of Biology

Section 1?1 What Is Science? (pages 3?7)

Key Concept ? What is the goal of science?

What Science Is and Is Not (page 3)

1. What is the goal of science?

2. What is science?

Thinking Like a Scientist (page 4)

3. What is observation?

4. The information gathered from observation is called

.

5. Complete the table about the types of data.

TYPES OF DATA

Type

Data Involves . . . Numbers

Example

Characteristics that cannot be easily measured or counted

6. What is an inference?

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Explaining and Interpreting Evidence (page 5)

7. What is a hypothesis?

8. In science, a hypothesis is useful only if it can be

.

9. Is the following sentence true or false? A hypothesis should be stated in such a way

that it can never be proved wrong.

10. What are three sources from which hypotheses may arise?

a.

b.

c.

11. Circle the letter of each of the following that may be an outcome of testing a hypothesis.

a. The hypothesis is partly true but needs to be revised.

b. The hypothesis is wrong.

c. The hypothesis is supported.

d. The hypothesis is of no value.

Science as a Way of Knowing (page 6)

12. What do scientists assume about the universe?

13. What are some qualities that are desirable in a scientist?

Science and Human Values (page 7)

14. Is the following sentence true or false? A community must use its shared values to make decisions about scientific issues.

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Section 1?2 How Scientists Work (pages 8?14)

Key Concepts ? How do scientists test hypotheses? ? How does a scientific theory develop?

Designing an Experiment (pages 8?10)

1. The idea that life can arise from nonliving matter is called .

2. What was Francesco Redi's hypothesis about the appearance of maggots?

3. What are variables in an experiment? 4. Ideally, how many variables should an experiment test at a time?

5. What is a controlled experiment?

6. The illustration below shows the beginning of Redi's experiment. Complete the illustration by showing the outcome.

Redi's Experiment on Spontaneous Generation

Uncovered jars

Covered jars

Several days pass.

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7. Complete the table about variables.

VARIABLES

Type of Variable

Definition

Manipulated variable

Responding variable

8. In Redi's experiment, what were the manipulated variable and the responding variable?

9. For what do scientists use the data from a controlled experiment? 10. When scientists look for explanations for specific observations, what do they assume

about nature?

Repeating Investigations (pages 10?12)

11. Why do scientists assume that experimental results can be reproduced?

12. What did Anton van Leeuwenhoek discover?

13. What did John Needham conclude from his test of Redi's findings?

14. What did Spallanzani do to improve upon Redi's and Needham's work?

15. How did Pasteur settle the spontaneous generation argument?

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When Experiments Are Not Possible (page 13)

16. In animal field studies, why do scientists usually try to work without making the animals aware that humans are present?

17. When a controlled experiment is not possible, why do scientists try to identify as many relevant variables as possible?

How a Theory Develops (pages 13?14)

18. In science, what is a theory? 19. Is the following sentence true or false? A theory may be revised or replaced by a more

useful explanation.

Reading Skill Practice

A flowchart can help you remember the order in which a set of events has occurred or should occur. On a separate sheet of paper, create a flowchart that represents the process that Redi carried out in his investigation of spontaneous generation. This process is explained under the heading Designing an Experiment on pages 8?10. For more information about flowcharts, see Organizing Information in Appendix A of your textbook.

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Section 1?3 Studying Life (pages 15?22)

Key Concepts ? What are some characteristics of living things? ? How can life be studied at different levels?

Introduction (page 15)

1. What is biology?

Characteristics of Living Things (pages 15?17)

2. What is a cell?

3. Circle the letter of each sentence that is true about cells.

a. A cell is the smallest unit of an organism that can be considered alive.

b. A multicellular organism may contain trillions of cells.

c. A living thing that consists of a single cell is a multicellular organism.

d. Organisms are made up of cells.

4. What are two types of reproduction?

a.

b.

5. Living things are based on a universal

.

6. Circle the letter of each sentence that is true about living things.

a. The life cycle of many organisms involves development.

b. For bacteria, growth is mostly a simple increase in size.

c. Each type of organism has a distinctive life cycle.

d. Cells may change in number but never differentiate.

7. Why does an organism need energy and a constant supply of materials?

8. Is the following sentence true or false? All organisms respond to the environment in exactly the same ways.

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