LECTURE 1: INTRODUCTION

I. Biology is "the science of life."

A. Biology is a natural science.

B. Biologists study studies a variety of biological systems.

II. What do biologists study?

A. Biologists study hierarchical biological systems.

1. The cell — the basic unit of life — e.g. a muscle cell.

2. Tissues — e.g. muscle tissue.

3. Organs — e.g. bicep muscle.

4. Organ systems — e.g. muscular system.

5. Organism — e.g. a jackrabbit.

6. Population — e.g. jackrabbits on a 50-acre plot in ABDSP.

7. Community — e.g. mammal community on the 50-acre plot in ABDSP.

8. Ecosystem — e.g. desert ecosystem.

9. The biosphere.

B. Biology is made up of smaller sciences — some examples.

1. Ecology.

2. Genetics.

3. Physiology.

III. Biodiversity.

A. Earth is home to a tremendous diversity of life forms.

B. Taxonomists identify and name life forms.

1. The species is the basic taxonomic unit.

2. Species are given unique 2-word names — e.g. Homo sapiens.

3. Taxonomists have named about 1.7 million different species!

C. So, how many species are there?

1. No accurate answer.

2. Estimates range between 5 million and 30 million species!!

IV. Taxonomy -- the science of naming and classifying organisms.

A. Taxonomy uses a hierarchical system of classification.

B. Species put into larger groups based on similarity.

1. Example: Canis familiaris, Canis lupus, Canis latrans.

2. Example: canids, felids, bears, etc.

C. The highest taxonomic category: the domain.

D. Domains are made up of kingdoms. (Figure 1.8)

 

E. Why are species similar?

1. Species are similar because they are related.

2. Species have evolved from a common ancestor.

V. Evolution: Biology’s unifying theme.

A. Evolution is a process of genetic change over time.

B. Populations become new species.

C. Species are related to one another.

D. Figure 1.11: The "genealogy" of bears.

E. All life forms are the descendents of a common ancestor.

F. Evolution is the process that has generated biodiversity on Earth.

VI. Biology and The Scientific Method.

A. The scientific method: a general "problem-solving" procedure.

B. Five steps.

1. Observation.

2. Hypothesis.

3. Prediction.

4. Experiment.

5. Decision.

C. Some miscellaneous points.

1. A hypothesis must be testable and potentially falsifiable.

2. Hypotheses can never be proven.

3. False hypotheses lead to new hypotheses.

4. Hypotheses may be repeatedly tested.

5. Theories, principles and laws.

D. A real example: lemming "cycles."

1. Observation.

2. Hypothesis: It’s the food!

3. Prediction.

4. Experiment — design issues.

5. Decision — the use of statistics.

VII. The Relevancy of Biology 100.

A. This is one of the most relevant classes you’ll ever take.

B. We are organisms!

1. Everyday things.

2. Global and societal things.

Next time: Chemistry for Biology.