Topic: Introductory Biology

Advances in Neurotechnology
In this video segment from Greater Boston, learn how a man with severe motor disabilities can operate a computer and move a prosthetic hand by simply thinking the commands, thanks to the combined efforts of bioengineers and neuroscientists.

All in the Family
In this Evolution Web feature, test your skills at judging who's who on the tree of life while you learn about the tools and methods of cladistics.

Alzheimer's Disease
This video segment from the Secret of Life School Video: "Genetic Medicine: Tinkering with Our Genes" explores the potential for gene therapy to cure diseases like Alzheimer's.

Animal Body Plans: Homeobox Genes
The homeobox genes that define the basic body plan of mice and fruit flies are illustrated in this graphic from The Human Evolution Coloring Book by Adrienne Zihlman. The accompanying article describes how these genes act as "molecular architects" in all animal species.

Biological Invaders
This video segment from Evolution: "Extinction!" shows the impact of invasive species on native ecosystems.

Blood Flow and Thermoregulation
In this interactive activity adapted from the University of Alberta, learn about the ways your body can regulate its temperature.

Bt Corn
This video segment from FRONTLINE/NOVA: "Harvest of Fear" looks at corn that has been genetically modified to resist one insect pest, and the multiple concerns it raises.

Carnivorous Plants of Texas
In this video adapted from Texas Parks and Wildlife Department, learn about carnivorous plants that act as both producers and consumers in an ecosystem. See sundews and blatterworts capture and digest insects.

Cell Differentiation
In this video segment from The Secret of Life school video, "Sex and the Single Gene" follow as a single fertilized egg cell divides, differentiates, and assembles into the tissues and organs of a new organism.

Cell Membrane: Just Passing Through
This interactive feature describes some of the most important structures and functions of the cell membrane.

Changing Arctic Landscape
In this video adapted from the Arctic Athabaskan Council, learn how warmer temperatures in the Arctic are transforming the landscape, triggering a host of effects such as permafrost thawing and insect infestations.

Chromosome Viewer
This interactive feature provides a microscopic view of the 24 Human chromosomes. Each chromosome is labeled with the names of some of the genetic conditions and traits associated with particular regions on that chromosome.

The Common Genetic Code
Paul Nurse describes his research that showed that humans share some genes with organisms as different from us as simple brewer's yeast. Footage from Secret of Life: "Immortal Thread."

Complex Relations
In this text excerpted from chapter 3, "Struggle for Existence," of Charles Darwin's On the Origin of Species, Darwin draws on firsthand and historical information for his observations about evolution.

Contaminants in the Arctic Human Population
In this video segment adapted from LOKE Films and the Arctic Monitoring and Assessment Programme, learn how human populations in the Arctic are affected by industrial contaminants in the food chain.

Cow's Eye Dissection
In this interactive activity adapted from the Exploratorium, watch videos of a cow eye dissection and see how an eye works.

Darwin: Reluctant Rebel
This video segment from Evolution: "Darwin's Dangerous Idea," together with interviews with Daniel Dennett and James Moore, depicts Darwin struggling with publicizing his revolutionary theory.

Darwin's Letters: Collecting Evidence
This group of letters is a sample of the extensive correspondence Darwin carried on with a wide group of friends and colleagues as he collected evidence to support his theory of evolution by natural selection. From Charles Darwin's Letters: A Selection 1825-1859.

Deep Sea Vents and Life's Origins
Deep-sea vents are home to strange, luminescent life forms that thrive through chemosynthesis. This video segment from NOVA: "Volcanoes of the Deep" hypothesizes life's beginnings in this extreme environment.

Dengue Virus Invades a Cell
In this visualization adapted from the University of Massachusetts Medical School, discover the role that dengue viral proteins play in a human cell as the virus prepares to replicate.

DNA Databases
This video segment from NOVA: "Cracking the Code of Life" investigates the promises and concerns surrounding the use of DNA databases.

DNA Fingerprint Photos
These photographs supplied by Genelex Corporation depict actual DNA fingerprints and show the types of information that can be gleaned from them.

DNA on the Witness Stand
In this article, Dr. Eric Lander of the Human Genome Project comments on the use of DNA as an identification tool -- the theoretical versus the practical results.

Double Immunity
Dr. Stephen O'Brien of the National Cancer Institute discovers a 700-year-old mutation that makes a person resistant to HIV infection. From Evolution: "Evolutionary Arms Race."

The Embryo Takes Shape
This video segment from NOVA: "Life's Greatest Miracle" explores the developmental process of an embryo beginning just two weeks after fertilization.

E. O. Wilson: Ants and Ecosystems
This segment is from an interview with ant specialist and biologist E.O. Wilson, filmed for Evolution: "Evolutionary Arms Race."

Evolution on Double Time
This excerpt from Evolution: The Triumph of an Idea by Carl Zimmer describes how gene duplication may have been the key to the rapid evolution of the early stages of life on Earth.

Evolving Ideas: Did Humans Evolve?
This video from Evolution explores the evolution of humans from a common ancestor of humans, chimpanzees, and other apes.

Evolving Ideas: How Do We Know Evolution Happens?
This video from Evolution focuses on one of the several lines of evidence for evolution -- fossils, highlighting the evolution of whales from land-dwelling mammals to the aquatic creatures we know today.

Evolving Ideas: Why Does Evolution Matter Now?
In this video from Evolution, an exploration of multi-drug resistant tuberculosis in the Russian prison system highlights one reason it is important to understand evolution.

A Family Disease
This video segment from NOVA: "Cracking the Code of Life" explores the implications of genetic testing for breast cancer.

Finding Cures Is Hard
This video segment from NOVA: "Cracking the Code of Life" explains the difficulty of curing genetic diseases such as cystic fibrosis.

Finding Lucy
This Evolution video segment depicts the landmark hominid fossil finds by Don Johanson and his team in Ethiopia.

Floral Arrangements
Explore a few of the ways plants pollinate each other in this video segment from Sexual Encounters of a Floral Kind.

Fossils
Fossils are indicators of past life. This collection of still images produced for Teachers' Domain features examples of fossils from plants, animals, and insects.

Frozen Frogs
This video segment adapted from NOVA scienceNOW shows how the common wood frog freezes solid every winter, an adaptation that allows the organism to survive the cold winter.

Gallery of Visual Illusions
Are your eyes playing tricks on you? Discover more about eyesight and the brain as you test your eyes with these visual illusions adapted from the University of Washington's Neuroscience for Kids Web site.

Gene Control
The development of creatures that appear to have nothing in common is directed by a surprisingly small number of genes. In this video segment, learn about the power of master control genes. Footage from The Secret of Life: "Birth, Sex & Death."

Genetic Drift and the Founder Effect
This image of polydactyly illustrates one symptom of Ellis-van Creveld syndrome, which is commonly found in the Amish. Ellis-van Creveld is one example of the founder effect and genetic drift.

Genetic Modification
This video segment from NOVA: "Cracking the Code of Life" looks at the potential created by understanding the human genome.

Genetics: Tour of the Basics
In this interactive activity from the University of Utah, identify different kinds of genetic traits and how they are passed on from generation to generation. View examples of simple and complex trait inheritance.

Genetic Tool Kit
The shared set of genes for body segments, possessed by all animals, are discussed in this video segment from Evolution: "Great Transformations."

Genome Facts
This list from NOVA: "Cracking the Code of Life" Web site provides some of the basic, yet impressive, facts and figures about the Human Genome Project.

Global Warming and the Greenhouse Effect
This video segment from Race to Save the Planet: "Only One Atmosphere" discusses the greenhouse effect and global warming.

The Grand Canyon: Evidence of Earth's Past
In this video segment adapted from NOVA, a fossil found among the Grand Canyon's rock layers reveals the existence of a shallow sea that once covered most of western North America.

The Science Behind Appetite
This video segment, adapted from NOVA, tells the story of a ballerina battling anorexia. It explains how serotonin regulates appetite, and presents some of the health risks that accompany the eating disorder.

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

How Cells Divide: Mitosis vs. Meiosis
How exactly does meiosis mix and halve chromosomes? Find out through this feature from NOVA: "18 Ways to Make a Baby," which provides a step-by-step, side-by-side comparison of meiosis and mitosis.

How DNA Evidence Works
In this article by An Meeker-O'Connell, discover how DNA evidence is processed before it goes to court.

How Genetic Disorders Are Inherited
Learn how genetic disorders are passed from parents to children as explained in this excerpt from Blazing a Genetic Trail, from the Howard Hughes Medical Institute.

Human Genome Project
This video segment from NOVA: "Cracking the Code of Life" looks at the meaning and significance of the effort to decode the human genome.

Ingredients for Life: Water
This video segment adapted from NOVA goes on a whimsical journey in search of life forms thriving in extreme conditions on Earth and in outer space. Animations show ice on Jupiter's moon, Europa, and signs that water once existed on Mars.

Inuit Observations of Climate Change
In this video adapted from the International Institute for Sustainable Development, an Inuit community collaborates with Western scientists studying climate change. Inuit observations are recorded and included in the data collection process, expanding the scientists' understanding of changes in the area.

Isolating Mechanisms: Lacewing Songs
Hear the different songs of three lacewing flies, which serve as reproductive isolating mechanisms between species and determine mate choice. Lacewing audio song from Charles Henry.

The Kemps Ridley Sea Turtle
This video adapted from Texas Parks and Wildlife Department describes how humans are helping restore safe nesting grounds for the critically endangered Kemp's ridley sea turtle to ensure its successful repopulation.

Laetoli Footprints
This Evolution video segment describes how the famous track fossils known as the Laetoli footprints might have been formed and what they can reveal about the creatures who left them.

Leafy Spurge
This video segment from Evolution: "Extinction!" shows how biological control is successfully combating North Dakota's infestation of leafy spurge, a non-native plant.

Life Cycle of a Seed Plant
In this interactive activity adapted from the University of Alberta, learn about each step in the life cycle of a seed plant.

Life's Little Essential: Liquid Water
Why is water necessary for life? Why is it the best and possibly only liquid to do the job? This illustrated essay from NOVA Online answers these questions, explaining why planetary scientists are on the lookout for water elsewhere in the solar system.

Mike Novacek: Fossils in the Gobi
Biologist Mike Novacek discusses his discovery of mammal fossils in the Gobi Desert and what we can learn from them. From Evolution: "Extinction!"

Mirror Neurons
This video segment, adapted from NOVA scienceNow, introduces the latest research on a system of neurons that plays a part in how people relate to each other.

Mitochondrial Flyover
This video segment illustrates the three-dimensional structure of a mitochondrion, the organelle that powers nearly every cellular process in your body.

Molecular Clocks: Proteins That Evolve at Different Rates
From The Human Evolution Coloring Book by Adrienne Zihlman, four different proteins from humans and horses are compared in this graphic and article, and the reasons each protein evolves at its own characteristic rate are discussed. Each protein is useful for measuring evolutionary change over a different time scale.

Mouse Party
In this interactive activity from The University of Utah, examine the molecular mechanisms that affect the brains of mice on drugs. Learn how different drugs create different responses in the brain and alter the natural state of a mouse.

Nature's Pharmacy
In this interactive activity from NOVA, learn about chemicals in nature that are used in medicine.

A Night in the Coral Reef
Coral reefs are often portrayed as brightly lit, bustling underwater marvels full of colorful creatures. This video segment, adapted from NOVA, paints a different picture as it explores the nocturnal behavior of organisms in the reef.

The Nitrogen Cycle
Nitrogen, one of the most abundant elements in the universe, is essential to life. This interactive activity adapted from the University of Alberta provides an overview of the nitrogen cycle.

Oil Spill: Exxon Valdez, 1989
This video segment adapted from NOVA follows the clean-up effort after the 1989 Exxon Valdez oil spill off the coast of Alaska. Also featured is a marsh where an oil spill occurred 20 years earlier; analysis suggests that environmental damage may last for decades.

One Wrong Letter
This video segment from NOVA: "Cracking the Code of Life" describes the genetics of Tay-Sachs disease.

Organelles in the Cytoplasm
In this video segment from An Introduction to the Living Cell, explore the inner workings of a cell, including some of its most important organelles.

Origins of Humankind
In this Evolution feature, examine a six-million-year-long fossil record to learn about the evolution of the human family.

Penguin Response to Climate Change
Find out how climate change is affecting Antarctic Adélie penguins and their ecosystem in this video segment adapted from Lloyd Fales and Sweetspot Pictures, Inc.

Polar Bears and Climate Change
In this video from the World Wildlife Fund, learn how rising temperatures in the southern Arctic could lead to polar bear extinction.

Preimplantation Genetic Diagnosis
This video segment from NOVA: "18 Ways to Make a Baby" describes a technique used to determine the health of a developing embryo.

Record of Time
Enter the exciting world of dating ... fossil dating, that is. From Record of Time by anthropologist Dennis O'Neil.

Riddle of the Bones
In this Evolution Web feature, piece together clues to how one of our early ancestors looked as you examine images from four significant fossil finds of Australopithecus afarensis.

RNAi Explained
Using scientific animations and illustrated metaphors, this interactive activity from NOVA scienceNOW explains RNAi and how it works.

Sequence for Yourself
How do researchers read the tiny As, Gs, Ts, and Cs that comprise DNA? This step-by-step explanation shows you. From NOVA: "Cracking the Code of Life."

Sex and the Single Guppy
Play in our streams and see how exhibitionism has an evolutionary payoff in this Evolution simulation of Endler's experiment.

Should We Create Babies by Design?
Should we attempt to control our heredity? Take our poll, developed for the Evolution Web site.

Simple Solutions
Amy Smith is an engineer who designs simple and inexpensive solutions to real-world problems. This video produced for Teachers' Domain features her innovative design for testing the safety of drinking water in the developing world.

Stem Cells Breakthrough
In this video segment adapted from NOVA scienceNOW, follow the scientific process that led to a revolutionary method for creating stem cells without the use of human embryos.

Stories in the Ice
Take a journey back through time, using ice cores to learn about the Earth's climatic history. From the FRONTLINE/NOVA: "What's Up with the Weather?" Web site

Sweaty T-shirts and Human Mate Choice
This video segment from Evolution: "Why Sex?" explores the "sweaty T-shirt experiment," which showed that humans may unconsciously be drawn toward a specific kind of genetic variation in a mate.

Tale of the Peacock
The peacock provides a classic example of sexual selection, the force behind nature's extravagances. From Evolution: "Why Sex?"

Three Ways to Check a Fetus's Chromosomes
This figure from Human Genetics: Concepts and Applications by Ricki Lewis identifies techniques used to collect cells from fetuses for genetic testing.

Tracing Human Evolution to Its Roots
This graphic from Biology by Kenneth R. Miller and Joseph Levine suggests how some recent hominid fossil finds might fit into the overall picture of hominid evolution. As more fossils are found and further analysis advances our understanding of human evolution, this picture will almost certainly be revised.

Transitional Tetrapod Fossil
In this video segment from NOVA: "Judgment Day: Intelligent Design on Trial," learn about the discovery of a well-preserved transitional fossil and how such transitional fossils support the theory of evolution.

Types of Fossils
This interactive resource adapted from the University of California Museum of Paleontology features images of body fossils, trace fossils, and a combination of the two.

The Value of Wetlands
This video segment adapted from Texas Parks and Wildlife Department explores the role of the wetlands in our environment, including providing habitats for wildlife, acting as natural water filters, and playing a part in the greater water cycle.

Walking Tall
This video segment from Evolution: "Great Transformations" illustrates the differences between the skeletons of a chimpanzee (a knuckle-walker) and a human (a biped).

Whales in the Making
This graphic from Evolution, traces the evolution of whales from land-dwelling mammals to the aquatic creatures we know today.

What Killed the Dinosaurs?
In this Evolution Web feature, find clues to one of life's most compelling mysteries, and discover how evidence can support a variety of hypotheses.

Wild Animal Rehabilitation
In this video adapted from Texas Parks and Wildlife Department, see how volunteers care for sick or injured animals. Also learn why human interaction is not always the best solution.