Although repeatedly exposed to HIV, Steve Crohn's blood cells were never infected. Dr. David Ho investigates in this video segment from NOVA: "Surviving AIDS."

In this biodiversity activity, students learn how to construct their own cladogram. They consider four coins (quarter, dime, nickel, penny), identifying defining characteristics. Then, students construct a Venn diagram, followed by a cladogram. The two-page printable PDF includes tips for both teachers and students.

In this biodiversity activity, students learn how to construct their own dichotomous keys. They use either specimens they've collected or ones you bring into class, such as shells, fruit, or leaves. The one-page printable PDF includes guidelines about what students should look for and include when creating their dichotomous keys.

These hands-on, minds-on activities engage students in experiments or simulation activities and incorporate multiple questions designed to foster student understanding of important concepts in the life sciences. Topics covered include biological molecules, diffusion, metabolism, cell division, genetics, molecular biology, evolution, diversity, human physiology and design and interpretation of experiments. These activities were designed for teaching high school or middle school students, but many of these activities can also be used in non-major introductory college biology classes. To accommodate limited budgets, most of these activities can be carried out with minimum equipment and expense for supplies. Additional minds-on activities for teaching biology, including discussion activities, are available at http://serendip.brynmawr.edu/exchange/bioactivities. Most of the activities are described in student handouts and teacher notes; the student handouts are available as Word files for teachers to customize for their students.

In this video segment adapted from United Tribes Technical College, meet Native Americans who are concerned about climate change and believe that action today can help future generations once again live in harmony with Earth.

Learn how a cow eats and digests food in this video segment from Nature.

This minds-on, hands-on activity begins with analysis and discussion questions that develop student understanding of homeostasis and negative feedback and the differences between negative and positive feedback. Next, students develop a model of negative feedback regulation of blood levels of CO2 and O2 as they learn or review basic information about cellular respiration and basic physiology of the respiratory and circulatory systems. Then, students carry out an experiment to test their negative feedback model and analyze the data. In a final optional section, students develop and carry out an independent investigation. This activity helps students meet the Next Generation Science Standards.

This video segment, adapted from NOVA, explores reasons why Homo sapiens had an advantage over Neanderthals in the pursuit of territory and natural resources.

In this video from Outdoor Nevada, learn about the habitat, diet, and defense mechanisms of horned lizards.

In this lesson about cosmic rays, students will describe why cosmic rays are dangerous to astronauts. Includes information about student preconceptions. This is activity 3 of 4 from "The Cosmic Ray Telescope for the Effects of Radiation (CRaTER)."

This narrated animation from Interactive NOVA: "The Secret of Life" illustrates DNA replication.

This video segment adapted from NOVA describes the emergence of life on the islands of Hawaii from a barren volcanic platform under the ocean waves to the rich explosion of life that covers the many climate zones of the islands today.

This analysis and discussion activity introduces students to the basic principles of how biological organisms use energy. The focus is on understanding the roles of ATP and cellular respiration. In addition, students apply the principles of conservation of energy and conservation of matter to avoid common errors and correct common misconceptions. This activity helps students meet the Next Generation Science Standards.

This analysis and discussion activity reinforces student understanding of the process of meiosis and the importance of having exactly the right number of copies of each chromosome in our body's cells. This activity also helps students to understand that miscarriages are often the result of genetic abnormalities and that genetic conditions sometimes are not inherited (e.g. Down syndrome due to meiotic nondisjunction). Optional additional questions can be used to promote student understanding of sex chromosome abnormalities and X chromosome inactivation.

In this activity, students analyze evidence from comparative anatomy, mathematical modeling, and molecular biology. This evidence suggests a likely sequence of steps in the evolution of the human eye and the octopus eye.  General concepts used to interpret this evidence include natural selection, fitness, and the difference between homology (similarity due to common descent) and analogy (similarity due to convergent evolution). This activity helps students meet the Next Generation Science Standards.

In this kinesthetic activity, the concept of energy budget is strengthened as students conduct three simulations using play money as units of energy, and students serve as parts of a planetary radiation balance model. Students will determine the energy budget of a planet by manipulating gas concentrations, energy inputs and outputs in the system in this lesson that supports the study of climate on Mars, Mercury, Venus and Earth. The lesson supports understanding of the real-world problem of contemporary climate change. The resource includes a teacher's guide and several student worksheets. This is the second of four activities in the lesson, How do Atmospheres affect planetary temperatures?, within Earth Climate Course: What Determines a Planet's Climate? The resource aims to help students to develop an understanding of our environment as a system of human and natural processes that result in changes that occur over various space and time scales.

In this activity, students simulate the interaction of variables, including carbon dioxide, in a radiation balance exercise using a spreadsheet-based radiation balance model. Through a series of experiments, students attempt to mimic the surface temperatures of Earth, Mercury, Venus and Mars, and account for the influence of greenhouse gases in atmospheric temperatures. The activity supports inquiry into the real-world problem of contemporary climate change. Student-collected data is needed from activity A in the same module, "How do atmospheres interact with solar energy?" to complete this activity. Included in the resource are several student data sheets and a teacher's guide. This activity is part of module 4, "How do Atmospheres Affect Planetary Temperatures?" in Earth Climate Course: What Determines a Planet's Climate? The course aims to help students to develop an understanding of our environment as a system of human and natural processes that result in changes that occur over various space and time scales.

In this lesson, students investigate the life history characteristics of different Antarctic penguin species and identify the changes that their populations have experienced.

Students develop a basic understanding of how taste and olfactory receptor cells function and how sensory messages to the brain contribute to flavor perception and flavor-related behavior. Students plan a hands-on investigation, carry out the investigation, analyze the data, and interpret the results. This activity helps students meet the Next Generation Science Standards.

In this video segment adapted from NOVA, follow novice runners as they train for a marathon, and discover how quickly the body responds to regular aerobic exercise.