Chapter 1 Introduction: Themes in the Study of Life

What are Themes? General principles or ideas that occur over and over. In the new AP curriculum, the themes are “the Big Ideas”.

The 4 Big Ideas: E2 – I2 1. Evolution 2. Energy 3. Information 4. Integration

The Big Ideas – E2 - I2 1. Evolution – the process of evolution drives the diversity and unity of life. 2. Energy – biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis. 3. Information – living systems store, retrieve, transmit and respond to information essential to life processes. 4. Interactions – biological systems interact and these systems and their interactions possess complex properties.

Why Big Ideas? We will see the Big Ideas at various times throughout the course. The Big Ideas will be the “connectors” between the content of the course.

Question: How do we know what is alive and what is not? Biology is the study of Life. So, what are the properties of Life? Goal – not to memorize the list of characteristics, but to be able to discuss and apply them.

1. Order Living things are highly organized in structure and function.

Analyzing a biological structure gives us clues about what it does and how it works.

Structure and Function are related at all levels.

2. Reproduction Organisms reproduce their own kind.

3. Nucleic Acids Life on Earth uses the nucleic acids and codes for Heritable Information.

4. Growth & Development Organisms increase in size and complexity.

Growth - increase in size. Development - increase in complexity. Life - grows by internal changes.

5. Energy Processing Organisms take in energy and transform it to do work.

Organisms are “open” systems, they must continually take in energy.

6. Response To Environment Organisms respond to changes or stimuli in their environment.

7. Regulation Life processes must be controlled and adjusted. Organisms maintain their internal environment within tolerable limits by homeostasis. “homeo” = same “stasis” = state

8. Evolutionary Adaptation Organisms change over time because of successful adaptations to their environment.

Organisms must have successful adaptations, move, or die! Is this a “good” adaptation?

9. The Cell Is the “basic unit” of Life

10. Organisms die

Science is: A process. A way of “knowing”. Based on observations and experiments.

Observations: Are the “keystone” to Science. If it can’t be “observed”, it can’t be studied by the Scientific Method. Can be made through your senses or through the use of tools.

Two types of Science 1. Discovery or Descriptive Science Naturalists, human genome Based on observations, but may lead to experiments Inductive Reasoning – logic flows from a set of specific observations to a general conclusion

2. Hypothesis based Science Science by experimentation Hypothesis testing in the form of “If…then…” Deductive Reasoning - logic flows from general to specific

Example When I throw a ball in the air, why does it come back down? Inductive Whenever I have thrown a ball in the past, it always comes back down. Specific observations to general conclusion. Deductive Gravity attracts two objects. If I throw the ball into the air, then gravity should draw the ball to the earth.

Scientific Method: Outlines a series of steps for answering questions. Note – goal is NOT to memorize these steps. Obtains “evidence” through the use of experiments.

Scientific Method Steps 1. Identify the problem. 2. What is already known? 3. Formulate a hypothesis. 4. Conduct an experiment changing one variable at a time. (Why?) 5. Collect data. Have replicates. (Why?) 6.Compare data to hypothesis. Does the data support the hypothesis? 7. Conclusions and new hypothesis

Comment Nothing is ever proven in science. Can only be disproven Experiments either support or fail to support a particular hypothesis. Disproving a hypothesis is as important as supporting it. We will learn about the 7 Science Practices in Lab.

Theory (Capital T) Broader in scope than hypothesis. Not determined by single experiment, but have been supported by many experiments by many scientists. Comprehensive explanation supported by abundance of evidence. Theories allow predictions.

Examples of Theories Atomic Theory Gravitational Theory Theory of Relativity Cell Theory Theory of Evolution by Natural Selection

Lower case t theories Used in everyday language, but are NOT the same as a Theory. Not predictive, Not testable. Not supported by evidence Don’t confuse Theory with theory.

Basic Evolution Nothing in Biology makes sense except in the light of Evolution. Theodosius Dobzhansky American Biology Teacher 35:125-129, 1973.

Evolution Success is by: 1. Survival - the organism has to live. 2. Reproduction – the organism has to leave progeny behind.

Important Notes: 1. organisms survive because of their adaptations, they do not adapt to survive. 2. individuals do not evolve, populations do.

Evolution in AP Biology 1. What is the adaptive value of ________? 2. Why has ______ persisted over time? 3. How does _____ increase survival or reproduction?

Chapter Summary Big Ideas can provide a common framework for learning Biology. What are the characteristics of Life? How does Science work? Evolution’s role in the study of Biology.