CHAPTER 1 The Science of

Biology

1.1 What is Science?

What Science Is and Is Not

• Scientific ideas are open to testing, discussion, and revision.

Science as a Way of Knowing• Science is different from human endeavors

because – It deals only with the natural world– Data is collected in an orderly way to look for

patterns and connections– Explanations are based on evidence, not belief

The Goals of Science

• To provide natural explanations for events in the natural world.

• Use scientific explanations to understand patterns in nature and formulate predictions.

Science, Change, and Uncertainty

• Nature is still a mystery because science is constantly changing.

• Science rarely proves anything in absolute terms, so scientists aim for the best understanding of the natural world.

Scientific Methodology: The Heart of Science

• There isn’t any single “scientific method,” but a general

style of investigation called scientific methodology.• It involves observing,

making inferences and forming hypotheses, conducting experiments, collecting and analyzing data, and drawing conclusions.

Observing and Asking Questions

• Scientific investigations begin with observations.

• A good scientist should be able to “Think something that nobody has thought yet, while looking at something that everybody sees.” – Arthur Schopenhauer

Inferring and Forming a Hypothesis

• After posing questions, scientists use observations to make inferences.• Inference combined with creative

imagination can help to form a hypothesis.

Designing Controlled Experiments• Hypotheses should be

tested in controlled experiments.

• You need controlling variables to determine what is responsible for any changes that occur.

• Scientists use multiple control and experimental groups so they can replicate the experiment.

Collecting and Analyzing Data

• Quantitative Data – numbers obtained by counting or measuring

• Qualitative Data – descriptions that can not be counted

• To avoid error use a larger sample size. The larger the sample size, the more reliable the data is.

Drawing Conclusions• Use experimental data to support,

refute, or revise the hypothesis.• If the hypothesis is not fully

supported, you can reevaluate and design a new experiment.

When Experiments Are Not Possible

• Some hypotheses can be tested by observation.

• Some experiments are not possible because of ethics.

Weather Patterns

1.2 Science in Context

Exploration and Discovery: Where Ideas Come From

• Observations may be inspired by scientific attitudes, practical problems, and new technology

Scientific Attitudes• Curiosity, skepticism, open-

mindedness, and creativity help scientists generate new ideas• Skeptics question existing ideas and

hypotheses

Practical Problems

• Practical questions and issues inspire scientific questions, hypotheses, and experiments

The Role of Technology• Scientific discoveries may lead to new

technologies, which enable scientists to ask new questions or to gather data in different ways

Communicating Results: Reviewing and Sharing Ideas

• Communication and sharing of ideas are vital to modern science

Peer Review

• Scientists publish articles, which contain details about experimental conditions, controls, data, analysis, and conclusions

• These articles have been peer-reviewed by anonymous, independent experts, and allow researchers to share ideas and to test and evaluate each other’s work

Sharing Knowledge and New Ideas

• New scientific finding spark new questions• Each new questions leads to new

hypotheses and new experiments

Scientific Theories

• The word theory applies to a well-tested explanation that unifies a broad range of observations and hypotheses and that enables scientists to make accurate predictions about new situations

• No theory is considered absolute truth

Science and Society• Certain questions can’t be answered by

science alone.

• They involve the society in which we live, our economy, and our laws and moral principles.

Testing Mussels for Toxins

Science, Ethics, ad Morality• Pure science doesn’t include ethical

or moral viewpoints• Science can’t tell us why life exists or

what ways technology should be applied.

Avoiding Bias• Bias can be personal taste,

preference for someone or something, and social standards of beauty• Scientific data can be misinterpreted

or misapplied by scientists who want to pave a particular point

1.3 Studying Life

Characteristics of Living Things• Living things are made up

of basic unites called cells, are based on a universal genetic code, obtain and use material and energy, grow and develop, reproduce, respond to their environment, maintain a stable internal environment, and change over time

Big Ideas in Biology• All biological studies are tied

together by themes and methods of study that cut across disciplines.• The study of biology revolves around

several interlocking big ideas.

1. Cellular Basis of Life

• There are unicellular and multicellular organisms

• Cells in mulitcellular organisms have many different shapes, sizes, and functions

2. Information and Heredity

• Living things are based on universal genetic code

• The information coded in DNA can influence your future, like risks for developing illnesses, or hair color

3. Matter and Energy

• Life requires matter that serves as nutrients to build body structures, and energy fuels life’s processes

4. Growth, Development, and Reproduction

• All living things reproduce, and the young grow and develop as they mature

• During growth and development, generalized cells typically become more and more different and specialized for particular functions.

5. Homeostasis

• Living things maintain a relatively stable internal environment

• The breakdown of homeostasis may have serious or even fatal consequences.

6. Evolution• Evolutionary change links all forms of life to a

common origin• Evolutionary theory is the central organizing

principle of all biological and biomedical sciences

7. Structure and Function• Each major group of organisms has evolved its

own collection of structures that make particular functions possible

8. Unity and Diversity of Life

• All living things are fundamentally similar at the molecular level.

• All organisms are considered of a common set of carbon-based molecules, store information in a common genetic code, and use proteins to build their structures and carry out their functions

9. Interdependence in Nature

• All forms of life are connected into a biosphere and are linked to one another and to the land, water, and

air around them

• The relationship depends on the cycling of matter and the flow of energy

10. Science as a Way of Knowing• The job of science is to use

observations, questions, and experiments to explain the natural world in terms of natural forces and events

• Scientific research reveals rules and patterns that can explain and predict at least some events in nature

Fields of Biology

• Biology includes many overlapping fields that use different tools to study life from the level of molecules to the entire planet

Global Ecology

• Global ecological studies are enabling us to learn about our global impact

Biotechnology

• This field is based on our ability to “edit” and rewrite the genetic code

• Biotechnology raises ethical, legal, and social questions

Building the Tree of Life• Biologists have discovered and identified

roughly 1.8 million different kinds of living organisms

• They want to combine the latest genetic information with computer technology to organize all living things into a single universal “Tree of All Life”

Ecology and Evolution of Infectious Diseases

• Relationships between hosts and pathogens are constantly changing

• Organisms that can cause human disease have their own ecology, which involve our bodies, medicines we take, and our interactions with each other and the environment

Genomics and Molecular Biology

• These fields focus on studies of DNA and other molecules inside cells.

Performing Biological Investigations

• Biologists like other scientists, rely on a common system of measurement and practice safety procedures when conducting studies

Scientific Measurements• Most scientists use the

metric system when collecting data and performing experiments

• The metric system is a decimal system of measurement whose units are based on certain physical standards and are scaled on multiples of 10

Safety

• Careful preparation is the key to staying safe during scientific activities