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1.1 The Diversity of Life

1.2 Properties of Life

1.3 The Organization of Life

1.4 Biological Themes

1.8 Theory and Certainty

1.5 The Nature of Science

1.6 Science in Action: A Case Study

1.7 Stages of a Scientific Investigation

Animations
(Animation Requirements)

• Levels of Biological Organization
• Ecosystem Organization
• Homeostasis and Temperature Control
• Flow Diagram for Scientific Method
• Ozone Layer Depletion

Art Labeling Activities

• Levels of Biological Organization (plants)
• Levels of Biological Organization (animals)

Everyday Science. Sometimes the nature of scientific inquiry is most clearly revealed by applying it to everyday matters, like what happens to missing socks, or by contrasting it to fantasy by attempting to evaluate hypotheses about sea monsters, leprechauns, or Santa Claus.

1. What good is science if it can't tell me where all my single socks are going?
2. Other attempts to solve the missing sock mystery.
3. The scientific theory of Santa Claus.
4. Further tests of the Santa theory.
5. How to catch a leprechaun.
6. UFO's: Is seeing believing?
7. Yes, Virginia, there is a jackalope.
8. How a scientist came to believe in dragons.
9. Seeking a sea monster named Selma.

Introduction to AIDS
The year 2001 marked the 20th anniversary of the AIDS epidemic. Since the first case was reported on June 5, 1981, the United States has recorded over 780,000 AIDS cases and over 460,000 deaths. Worldwide, the figures are numbing: 60 million cases and 22 million dead. Three million people died of AIDS last year alone. AIDS is caused by a virus called HIV that attacks and destroys the immune system. It is transmitted by sex, needles, any anything else that transfers white blood cells. AIDS is fatal, and there is no cure.

The Challenge of Curing AIDS
Faced with the AIDS plague - no other word will do - scientists all over the world have sought a way to defeat the HIV virus. It has been a discouraging battle. The full nucleotide sequence of the virus is known, and researchers have pieced together a detailed picture of how it infects cells, but all attempts to prepare a vaccine targeted on the HIV coat protein have failed. HIV simply mutates too quickly for any one vaccine to protect many people. New, more promising approaches involve multiple proteins and cell-mediated as well as antibody-based immune defenses.

Catching Evolution in Action
To study evolution, biologists have traditionally investigated what has happened in the past by examining fossils. For biologists taking this traditional approach, evolutionary biology is similar to astronomy or history, relying on observation and deduction rather than experimentation. In recent years, however, case studies of natural populations have demonstrated that evolutionary change can occur rapidly, and be studied in action.

The guppy, Poecilia reticulata, offers an excellent experimental opportunity to follow evolutionary change. Guppies inhabit two very different environments in the streams of Venezuela and Trinidad. The streams contain waterfalls that are dispersal barriers to guppies and guppy predators. Guppies above the waterfalls experience little predation and are larger and more colorful than guppies below the waterfalls that share their environment with a voracious predator. Does pressure from predation affect the color and size of guppies? A classic set of laboratory and field experiments initiated by John Endler in the late 1970s demonstrated that natural selection was acting on the Trinidad guppies.