Chapter 1: Scientific Thinking

Your pathway to understanding the world

Learning Goals

• Describe what science is.• Describe what biology is.• Describe the major themes in

biology.• Describe the scientific method.• Describe how the scientific method

can be used to help make wise decisions.

What is a fact?

I prefer “body of evidence”. As new evidence is revealed, science changes!

Scientists Are curious Ask questions about how the world

works Seek answers

• Does the radiation released by cell phones cause brain tumors?

• Are anti-bacterial hand soaps better than regular soap?

• Do large doses of vitamin C reduce the likelihood of getting a cold?

Biology is the study of life.

What role does biology play in your life?

Defining Life…

5 Characteristics Unique to Living Things:

1. Composed of cells

2. Interacts and responds to other living things

3. Grows and reproduces

4. Actively transforms energy

5. Changes and adapts over time leading to a wide diversity of organisms

Influenza Virus

Why should we learn about Biology?

• All educated citizens should have a basic understanding about where we came from.– Evolution– Reproduction and

Genetics

Why should we learn about Biology?

• All educated citizens should have a basic understanding of themselves.– Be healthy

• Nutrition• Avoid disease

– Interactions with other living things

Why should we learn about Biology?

• All educated citizens should have a basic understanding about where we’re heading.– Human

evolution has made us the dominant animal.

The most important questions in biology:

What is the chemical and physical basis for life and its maintenance?

How do organisms use genetic information to build themselves and to reproduce?

What are the diverse forms that life on earth takes and how has that diversity arisen?

How do organisms interact with each other and with their environment?

The Cell is the smallest unit of life.

2 Main Kinds of Cells:

1. Prokaryotic

2. Eukaryotic

These cells differ structurally, but the chemical code (DNA) uses the same 4 letters of the alphabet, A, G, C, and T.

Hierarchical Organization:

Many levels of organization within the biosphere.

A cell is life’s basic unit of structure and function in all organisms – Biology

Each cell consists of an enormous number of chemicals cooperating to embody the properties of life – Chemistry

Organisms interact with other living things and their environment – Ecology

Hierarchical Organization: Until recently, 5 main kingdoms was the classification scheme.

• BacteriaBacteria and Archaea Archaea are prokaryotes. New evidence reveals important genetic differences.

• The domain EukaryaEukarya, contains 4 Kingdoms of eukaryotes.

•Debate continues on the kingdom level as new DNA comparisons are revealed.

The Power of Evolution: Biology’s Unifying Theme

Using fossil records, we trace the historical evolution of the bear.

From the fossils of primeval bacteria (3 billion years ago), we recognize connections to our own cells.

All Life is connected, and evolution is the unifying theme!

An evolutionary tree is only a hypothesis.

Evolution at Work!

1. Environmental Pressure = taking the antibiotic

2. Genetic variability = the gene for resistance

3. Successful Reproduction = pass that gene on to the next generation.

Abuse and misuse of antibiotics is speeding the evolution of resistant bacteria.

“How do you know that is true?”

The single question that underlies critical thinking

Critical thinking: To question with an open mind and search for truth using

reason and logic.

Can we trust the packaging claims that companies make?

clinical drug trials and evidence

CEO says: people “are really not scientifically minded enough to be able to understand a clinical study.”

Argument against labeling Genetically Modified foods… people won’t understand what it means.

Cloning Endangered Species

You don’t have to be at the mercy of charlatans, advertising, or slick packaging.

Learn exactly what it means to have scientific proof or evidence.

Learn what it means to think scientifically. Learn how to use the knowledge we gain to make

wise decisionsBiological Literacy:

Use the process of scientific inquiry to understand real world issues

Communicate your thoughtsIntegrate into your decision making

End

1.3 The scientific method is a powerful approach to understanding the world.If science proves some belief of

Buddhism wrong, then Buddhism will have to change

—Dalai Lama, 2005

Science helps us understand when we should change our mind.

Scientific Thinking Is Empirical…

…based on experience and observations that are rational, testable, and repeatable.Which answer below does not

exemplify knowledge gained through empirical testing?

1. Sugar tastes sweet.2. The sky looks blue during the daytime.3. I can smell freshly popped popcorn from

a distance.4. A rabbit’s foot can bring good luck.

The scientific method is a particularly effective approach because it is empirical, rational, testable, repeatable, and self-correcting.

Does taking echinacea reduce the intensity or duration of the common cold?

The goal is to: Propose a situation that will give a particular outcome if your hypothesis is true but that will give a different outcome if your hypothesis is not true.

Does echinacea help prevent the common cold?

Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold.

Repeatable experiments increase our confidence.

1.10 When do hypotheses become

theories?Two distinct levels of understanding that scientists use in describing our

knowledge about natural phenomena

A theory is a hypothesis for natural phenomena that is exceptionally well-supported by the data.A theory is broad in scope and has been tested repeatedly by independent researchers who come to the same conclusions, a large general body of supporting evidence.

Interpreting graphs and statistics can help us draw meaningful conclusions.

Does having access to a textbook help a student to perform better in a biology class?

Watch out for biases…

1.16 There are limits to what science can do.

The scientific method will never prove or disprove the existence of God.

Understand love?

What is beauty?