Chapter 1 Introduction: Themes in the Study of Life

What are Themes? u General principles or ideas that occur over and over. u “Themes” are not a test item, but they are a framework to organize the study of Biology.

AP Biology Themes 1. Science as a process 2. Evolution 3. Energy Transfer 4. Continuity and Change

AP Biology Themes 5. Relationship of Structure & Function 6. Regulation

AP Biology Themes 7. Interdependence in Nature 8. Science, Technology and Society

Why Themes? u We will see the “themes” at various times throughout the course. u Themes can be the basis of essay exams u Ex. Regulation of …

Question u How do we know what is alive and what is not? u What are the properties of Life?

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

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

u Structure and Function are related at all levels

2. Reproduction u Organisms reproduce their own kind.

u Life on Earth uses the nucleic acid as code for Heritable Information.

3. Growth & Development u Organisms increase in size and complexity.

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

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

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

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

u The speed of the response may be “fast” or “slow”.

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

7. Evolutionary Adaptation u Organisms change over time because of their adaptations to their environment.

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

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

9. Organisms Die or become non-life.

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

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

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

2. Hypothesis based Science u Science by experimentation u Hypothesis testing in the form of “If…then…” (no longer) u Deductive Reasoning - logic flows from general to specific

Example u When I throw a ball in the air, why does it come back down? u Inductive u Whenever I have thrown a ball in the past, it always comes back down u Specific observations to general conclusion

u Deductive u Gravity attracts two objects u If I throw the ball into the air, then gravity should draw the ball to the earth

Scientific Method: u Outlines a series of steps for answering questions. u 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. All other factors are held constant. (Why?)

Scientific Method Steps 5. Collect data. Have replicates (Why?) 6.Compare data to hypothesis. Does the data support the hypothesis?

7. Conclusions and new hypothesis.

Comments u Nothing is ever proven in science u Can only be disproven u Experiments either support or fail to support a particular hypothesis u Disproving a hypothesis is as important as supporting it

Theory u Broader in scope than hypothesis. u Not determined by single experiment, but have been supported by many experiments by many scientists.

Theory u Comprehensive explanation supported by abundance of evidence u Theories allow predictions

Examples of Theories u Atomic Theory u Gravitational Theory u Theory of Relativity u Cell Theory u Theory of Evolution by Natural Selection u Germ Theory u Chromosomal Theory of Inheritance

Facts and Laws u Fact: an objective and verifiable observation. Something that has been tested so many times there is no need to test anymore.objectiveverifiable observation u Law: considered universal and invariable facts of the physical world. A law is an analytic statement, usually with an empirically determined constant.

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

Success is measured by: 1. Survive 2. Reproduce Note – organisms survive because of their adaptations, they do not adapt to survive.

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

Summary u Themes can provide a common framework for learning Biology u What are the characteristics of Life? u What is Science and how does it work? u Evolution’s role in the study of Biology

Homework u Read Chapter 1 u Homework Questions u Due Next class period