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Topic: Introductory Biology

Resource Grade Level Media Type
1900 Air Pollution  

1900 Air Pollution
Examine this graph from FRONTLINE/NOVA: "What's Up with the Weather?" Web site to see dramatic increases in three greenhouse gases over the last two hundred years.

9-12 HTML Document
Advances in Neurotechnology  

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.

6-12 QuickTime Video
The Advantage of Sex  

The Advantage of Sex
Why did sex evolve? The likely answers, in this essay for the Evolution Web site by science journalist Matt Ridley, may surprise you.

9-12 HTML Document
All in the Family  

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.

6-12 Flash Interactive
Allopatric Speciation  

Allopatric Speciation
These images from the Smithsonian Institution depict Nancy Knowlton's work with snapping shrimp in Panama. Knowlton found that the closing of the isthmus -- dividing the Pacific Ocean from the Caribbean -- resulted in new species of shrimp.

9-12 JPEG Image
Alzheimer's Disease  

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.

9-12 QuickTime Video
Ancient Farmers of the Amazon  

Ancient Farmers of the Amazon
This video segment from Evolution: "Evolutionary Arms Race" tells the story of the leafcutter ant and the fungus it farms -- an example of mutually beneficial symbiosis.

6-12 QuickTime Video
Animal Body Plans: Homeobox Genes  

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.

9-12 PDF Document
Arctic Tundra  

Arctic Tundra
This video segment from Wild Europe: "Wild Arctic" explores the struggle for survival in one of Earth's most extreme environments.

3-12 QuickTime Video
Biological Invaders  

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

9-12 QuickTime Video
Biomes  

Biomes
This interactive resource adapted from NASA describes the different temperature, precipitation, and vegetation patterns in seven biomes: coniferous forest, temperate deciduous forest, desert, grassland, rainforest, shrubland, and tundra.

3-12 Flash Interactive
Blood Flow and Thermoregulation  

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

7-12 Flash Interactive
Blood Vessels Help Tumors Grow  

Blood Vessels Help Tumors Grow
In this video segment, adapted from NOVA, Dr. Judah Folkman uses the scientific method to discover how cancer cells induce the formation of new blood vessels, which in turn nourish those cancer cells.

6-12 QuickTime Video
Bt Corn  

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.

9-12 QuickTime Video
Build a Family Tree  

Build a Family Tree
Both sexes can use this interactive feature that lets you use DNA information from the Y chromosome to complete a male family tree. From the NOVA: "Lost Tribes of Israel" Web site.

9-12 Shockwave Interactive
Carnivorous Plants of Texas  

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.

K-12 QuickTime Video
Caves: Extreme Conditions for Life  

Caves: Extreme Conditions for Life
This video segment adapted from NOVA raises the provocative idea that if life can exist in the most extreme environments on Earth — such as in dark, toxic caves — then perhaps living things can also survive in harsh environments on other planets.

6-12 QuickTime Video
Cell Differentiation  

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.

6-12 QuickTime Video
Cell Division  

Cell Division
In this interactive activity adapted from the Exploratorium, explore the step-by-step process by which an animal cell divides to make more cells.

7-10 Flash Interactive
Cell Membrane: Just Passing Through  

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

6-12 Flash Interactive
Cell Transcription and Translation  

Cell Transcription and Translation
In this interactive activity adapted from the University of Nebraska, learn how and where transcription and translation occur within a cell and observe both processes in detail.

9-12 Flash Interactive
Changing Arctic Landscape  

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.

6-12 QuickTime Video
Chris Schneider: Rethinking Conservation  

Chris Schneider: Rethinking Conservation
In this interview filmed for Evolution: "Darwin's Dangerous Idea," biologist Chris Schneider discusses the relationship between conservation and speciation.

9-12 HTML Document
Chromosome Viewer  

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.

9-12 Flash Interactive
Classical vs. Transgenic Breeding  

Classical vs. Transgenic Breeding
This video segment from FRONTLINE/NOVA: "Harvest of Fear" explains that genetic engineering and classical breeding both alter the genetic makeup of crop plants.

9-12 QuickTime Video
The Common Genetic Code  

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."

9-12 QuickTime Video
Compare the Poles  

Compare the Poles
Explore the defining features of the Arctic and the Antarctic in this interactive activity adapted from the Woods Hole Oceanographic Institution.

3-12 Flash Interactive
Complex Relations  

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.

9-12 HTML Document
Contaminants in the Arctic Food Chain  

Contaminants in the Arctic Food Chain
The levels of contaminants found in particular animals vary widely depending on where they fit into the Arctic food chain, as described in this video segment adapted from LOKE Films and the Arctic Monitoring and Assessment Programme.

5-12 QuickTime Video
Contaminants in the Arctic Human Population  

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.

5-12 QuickTime Video
Continental Divide: The Breakup of Pangaea  

Continental Divide: The Breakup of Pangaea
Examine geological evidence found in fossils, rock deposits, and ancient mountains that supports the theory of continental drift in this interactive activity adapted from the Exploratorium.

6-12 Flash Interactive
Cow's Eye Dissection  

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.

6-12 Flash Interactive
Dance of Development  

Dance of Development
Watch the "dance" of development as a zebrafish egg divides and differentiates on its way to becoming an embryo in this interactive activity adapted from the Exploratorium.

9-12 Flash Interactive
Darwin: Reluctant Rebel  

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.

9-12 QuickTime Video
Darwin's Diary  

Darwin's Diary
Delve into the private thoughts of a reluctant revolutionary in this Evolution Web feature.

9-12 Flash Interactive
Darwin's Letters: Collecting Evidence  

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.

9-12 HTML Document
Darwin's Letters to Lyell  

Darwin's Letters to Lyell
In this letter written to his friend and mentor Charles Lyell less than three weeks after the publication of On the Origin of Species, Darwin describes the reaction of the great anatomist Richard Owen to his theory. From Charles Darwin's Letters: A Selection 1825-1859.

9-12 HTML Document
Deep Sea Vents and Life's Origins  

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.

3-12 QuickTime Video
Deep Time  

Deep Time
Explore 4 billion years of life on Earth and discover major transformations, geological changes, and extinction episodes in this Evolution Web feature.

6-12 Flash Interactive
Dengue Virus Invades a Cell  

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.

9-12 QuickTime Video
Desert Biome  

Desert Biome
This video segment from NOVA: "A Desert Place" describes the physical characteristics and organisms that define the desert biome.

3-12 QuickTime Video
DNA Databases  

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

9-12 QuickTime Video
DNA Evidence  

DNA Evidence
This audio segment is a National Public Radio story on New York State's DNA profiling of criminals.

9-12 QuickTime Audio
DNA Fingerprint Photos  

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.

9-12 PDF Document
DNA Makes History  

DNA Makes History
Read how DNA was used to solve the mystery of the Romanov family's execution. From Human Genetics: Concepts and Applications by Ricki Lewis.

9-12 PDF Document
DNA on the Witness Stand  

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.

9-12 PDF Document
DNA Workshop  

DNA Workshop
How does DNA perform those all-important functions of replication and protein synthesis? This interactive feature from the A Science Odyssey Web site will help you explore and understand the secrets of DNA.

9-12 Shockwave Interactive
Double Immunity  

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."

9-12 QuickTime Video
Electron Transport Chain  

Electron Transport Chain
This illustration from Biology by Kenneth R. Miller and Joseph Levine describes the steps of the electron transport chain, the second stage in the process of cellular respiration.

9-12 JPEG Image
The Embryo Takes Shape  

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.

9-12 QuickTime Video
Energy Flow in the Coral Reef Ecosystem  

Energy Flow in the Coral Reef Ecosystem
This video segment, adapted from NOVA, describes the energy flow in a coral reef, including its food web.

3-12 QuickTime Video
E. O. Wilson: Ants and Ecosystems  

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."

9-12 QuickTime Audio
Evolution of the Eye  

Evolution of the Eye
Zoologist Dan-Erik Nilsson demonstrates how the complex human eye could have evolved from simple light-sensitive cells. From Evolution: "Darwin's Dangerous Idea."

9-12 QuickTime Video
Evolution on Double Time  

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.

9-12 HTML Document
Evolution Revolution  

Evolution Revolution
From the Evolution Web site, explore the rise of a revolutionary idea and the controversies that surround it.

9-12 Flash Interactive
Evolving Ideas: Did Humans Evolve?  

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

9-12 QuickTime Video
Evolving Ideas: How Does Evolution Really Work?  

Evolving Ideas: How Does Evolution Really Work?
The process of evolution through natural selection is the focus of this video segment from Evolution, which presents a field study of hummingbird speciation in Ecuador.

9-12 QuickTime Video
Evolving Ideas: How Do We Know Evolution Happens?  

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.

6-12 QuickTime Video
Evolving Ideas: Who Was Charles Darwin?  

Evolving Ideas: Who Was Charles Darwin?
This video from Evolution highlights Charles Darwin's personal struggle to bring to light his theory of evolution through natural selection.

9-12 QuickTime Video
Evolving Ideas: Why Does Evolution Matter Now?  

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.

9-12 QuickTime Video
Explore a Stretch of Code  

Explore a Stretch of Code
Try your hand at reading a segment of genetic code in this interactive feature from the NOVA "Cracking the Code of Life" Web site.

9-12 Shockwave Interactive
A Family Disease  

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

9-12 QuickTime Video
Finch Beak Data Sheet  

Finch Beak Data Sheet
This graphic from Ecology and Evolution of Darwin's Finches by Peter Grant presents data from the Galapagos Islands, showing that a severe drought put selective pressure on the population of Darwin's finches and resulted in a change in the average beak size in the next generation.

9-12 PDF Document
Finding Cures Is Hard  

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.

9-12 QuickTime Video
Finding Disease Genes  

Finding Disease Genes
This video segment from NOVA: "Cracking the Code of Life" explains the process of finding genes that cause disease.

9-12 QuickTime Video
Finding Lucy  

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

9-12 QuickTime Video
Fish with Fingers  

Fish with Fingers
In this video segment from Evolution: "Great Transformations," paleontologist Jenny Clack explains that vertebrates evolved fingers before they invaded land.

6-12 QuickTime Video
Floral Arrangements  

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

6-12 QuickTime Video
Forensic DNA Analysis  

Forensic DNA Analysis
This video segment from NOVA: "The Killer's Trail" investigates the potential for DNA evidence to solve murder cases, even those from the distant past.

9-12 QuickTime Video
Fossils  

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.

3-12 Flash Image
From DNA to Protein  

From DNA to Protein
This narrated animation schematically shows the process of protein synthesis. Adapted from Interactive NOVA: "Secret of Life."

9-12 QuickTime Video
Frozen Frogs  

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.

6-12 QuickTime Video
Gallery of Cells  

Gallery of Cells
While all cells have a great deal in common, there is no end to the variation among them. These images provide a sense of the wondrous diversity found in the world of cells.

9-12 JPEG Image
Gallery of Visual Illusions  

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.

5-12 Flash Interactive
Gel Electrophoresis  

Gel Electrophoresis
This interactive activity from the Dolan DNA Learning Center illustrates the process of gel electrophoresis, in which DNA fragments are separated by size as they migrate at different rates through a gel matrix.

6-12 Flash Interactive
Gene Control  

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."

6-12 QuickTime Video
Genetic Art  

Genetic Art
Take a peek at the artistic side of science in this virtual exhibit, featuring work by Eva Sutton, Alexis Rockman and Sidney Harris.

9-12 PDF Document
Genetic Drift and the Founder Effect  

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.

9-12 JPEG Image
Geneticist Pardis Sabeti  

Geneticist Pardis Sabeti
In this video profile adapted from NOVA scienceNOW, learn about geneticist and rock musician Pardis Sabeti, whose innovative insights into natural selection demonstrated how beneficial mutations spread quickly through a population.

6-12 QuickTime Video
Genetic Modification  

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

9-12 QuickTime Video
Genetics Case Studies  

Genetics Case Studies
Wrestle with ethical issues concerning genetic rights and practices from the NOVA: "Cracking the Code of Life" Web site.

9-12 HTML Document
Genetics: Tour of the Basics  

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.

6-12 Flash Interactive
Genetic Therapy and Breast Tumors  

Genetic Therapy and Breast Tumors
This video segment from the Secret of Life School Video: "On the Brink: Portraits of Modern Science" explores the genetics of breast cancer.

9-12 QuickTime Video
Genetic Tool Kit  

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."

6-12 QuickTime Video
Genetic Variation  

Genetic Variation
This video segment from NOVA: "Cracking the Code of Life" explores the genetic similarities and differences among organisms.

9-12 QuickTime Video
Genome Facts  

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.

9-12 HTML Document
Global Trends Quiz  

Global Trends Quiz
In this interactive quiz from NOVA, take the Environmental Challenge and test your knowledge of human impact on the world's natural resources and climate.

3-12 Flash Interactive
Global Warming and the Greenhouse Effect  

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.

9-12 QuickTime Video
The Grand Canyon: Conservation and Development  

The Grand Canyon: Conservation and Development
This video segment adapted from NOVA explores the effects of the Glen Canyon Dam on the beaches, wildlife, and vegetation of the Colorado River.

3-12 QuickTime Video
The Grand Canyon: Evidence of Earth's Past  

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.

6-12 QuickTime Video
Guess What's Coming to Dinner?  

Guess What's Coming to Dinner?
Browse through a table full of genetically modified (GM) foods to see what's available now and what's to come. From the FRONTLINE/NOVA: "Harvest of Fear" Web site.

9-12 Flash Interactive
The Science Behind Appetite  

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.

5-12 QuickTime Video
HIV Immunity  

HIV Immunity
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."

9-12 QuickTime Video
<i>Homo Sapiens</i> Versus Neanderthals  

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.

6-12 QuickTime Video
How Cancer Grows  

How Cancer Grows
Follow the growth of a carcinoma from initial mutation to widespread metastasis in this feature from the NOVA: "Cancer Warrior" Web site.

6-12 Flash Interactive
How Cells Divide: Mitosis vs. Meiosis  

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.

6-12 Flash Interactive
How Did Life Emerge Here?  

How Did Life Emerge Here?
This video segment adapted from NOVA describes the emergence of life on the islands of Hawaiʻi 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.

3-12 QuickTime Video
How DNA Evidence Works  

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

9-12 PDF Document
How DNA Replicates  

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

9-12 QuickTime Video
How Genetic Disorders Are Inherited  

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.

9-12 PDF Document
Human Chromosome 2  

Human Chromosome 2
In this video segment adapted from NOVA: "Judgment Day: Intelligent Design on Trial," learn how modern genetics and molecular biology offer compelling support for evolution. The video features an interview with biologist Ken Miller.

6-12 QuickTime Video
Human Genome Project  

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.

6-12 QuickTime Video
Hummingbird Species in the Transitional Zones  

Hummingbird Species in the Transitional Zones
This video segment from Evolution: "Darwin's Dangerous Idea" shows biologists Chris Schneider and Tom Smith studying hummingbirds and other animals in Ecuador. Their research is investigating the processes by which new species are formed.

9-12 QuickTime Video
Ingredients for Life: Water  

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.

3-12 QuickTime Video
Intertidal Zone  

Intertidal Zone
This video segment from NOVA: "The Sea Behind the Dunes" explores the community of organisms that exists in the New England tidal marsh.

9-12 QuickTime Video
Inuit Observations of Climate Change  

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.

6-12 QuickTime Video
Is Love in Our DNA?  

Is Love in Our DNA?
Did evolution shape your taste in a mate? Take our interactive poll from Evolution.

9-12 HTML Interactive
Isolating Mechanisms: Lacewing Songs  

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.

9-12 Flash Interactive
Journey into DNA  

Journey into DNA
Travel deep into the human body to see exactly where your DNA resides. From the NOVA: "Cracking the Code of Life" Web site.

6-12 Flash Interactive
The Kemps Ridley Sea Turtle  

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.

3-12 QuickTime Video
Krebs Cycle  

Krebs Cycle
This illustration from Biology by Kenneth R. Miller and Joseph Levine describes the steps of the Krebs cycle, the critical first stage in the process of cellular respiration.

9-12 JPEG Image
Laetoli Footprints  

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.

6-12 QuickTime Video
Laetoli Trackways Diagram  

Laetoli Trackways Diagram
View a diagram of the hominid footprints that archaeologist Mary Leakey's team found at Laetoli in Tanzania.

9-12 JPEG Image
Leafy Spurge  

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.

9-12 QuickTime Video
Life Before Oxygen  

Life Before Oxygen
This Interactive NOVA: "Earth" video segment looks at ancient organisms that lived anaerobically, the origins of photosynthesis, and the new forms of life this process made possible.

3-12 QuickTime Video
Life Cycle of a Seed 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.

6-12 Flash Interactive
Life's Grand Design  

Life's Grand Design
Are nature's complex forms evidence of "intelligent design"? In this Evolution essay, biologist Kenneth Miller explains how the processes of evolution account for complex structures such as the human eye.

9-12 HTML Document
Life's Little Essential: Liquid Water  

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.

6-12 HTML Document
Microbe Clock  

Microbe Clock
In this Evolution Web feature, learn how mutation and fast reproductive rates can allow deadly microbes to outpace medical breakthroughs.

9-12 Flash Interactive
Mike Novacek: Fossils in the Gobi  

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!"

9-12 HTML Document
Mimicry: The Orchid and the Bee  

Mimicry: The Orchid and the Bee
In this photograph from Oxford Scientific Films, a horned bee attempts to mate with an Ophrys orchid, which has evolved to resemble a female bee.

9-12 JPEG Image
Mirror Neurons  

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.

6-12 QuickTime Video
Mitochondria Functions and Training  

Mitochondria Functions and Training
This essay by Owen Anderson describes the effects of physical exercise on the number and function of mitochondria inside muscle cells.

9-12 PDF Document
Mitochondrial Flyover  

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

9-12 QuickTime Video
Model Organisms  

Model Organisms
This interactive activity from the Dolan DNA Learning Center shows the different types of model organisms used in research and why each might be selected when performing an experiment.

9-12 Flash Interactive
Molecular Clocks: Proteins That Evolve at Different Rates  

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.

9-12 PDF Document
Molecular Level of Genetics  

Molecular Level of Genetics
Get down to the molecular nitty-gritty of DNA replication and protein synthesis in this article by Dennis O'Neil.

9-12 PDF Document
Mouse Party  

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.

9-12 Flash Interactive
A Mutation Story  

A Mutation Story
This video segment describes the role of the sickle cell gene in natural selection. Footage courtesy of the PBS series Secret of Life: "Accidents of Creation."

6-12 QuickTime Video
Nature's Pharmacy  

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

3-12 Flash Interactive
Nature vs. Nurture Revisited  

Nature vs. Nurture Revisited
Which dictates our existence -- our genetic makeup or the environment we grow up in? Kevin Davies offers an update on this long-standing debate, from the NOVA: "Cracking the Code of Life" Web site.

9-12 HTML Document
A Night in the Coral Reef  

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.

3-12 QuickTime Video
Nihoa Island  

Nihoa Island
This video segment adapted from the NOW-RAMP 2002 Expedition documents a research expedition to Nihoa Island. It showcases Nihoa's unique birds and plants, the threat posed by invading grasshoppers, and restoration efforts.

6-12 QuickTime Video
The Nitrogen Cycle  

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.

9-12 Flash Interactive
Nucleus, Cytoplasm, Membrane  

Nucleus, Cytoplasm, Membrane
Explore the form and function of three of the most important cell parts -- the nucleus, cytoplasm, and membrane -- in this video segment adapted from Carolina Biological Supply's An Introduction to the Living Cell.

9-12 QuickTime Video
Oil Spill: <em>Exxon Valdez</em>, 1989  

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.

6-12 QuickTime Video
Romiya Glover  

Romiya Glover
In this video from Science City, meet Romiya Glover, a chemist who develops products for HIV/AIDS testing. She describes the multidisciplinary nature of her job, how she decided to go into science, and how her work benefits others.

6-12 MPEG 4 Video
One Wrong Letter  

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

6-12 QuickTime Video
On Human Cloning  

On Human Cloning
Three cloning experts share their opinions in these interviews from the NOVA "18 Ways to Make a Baby." Web site.

9-12 HTML Document
Organelles in the Cytoplasm  

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.

9-12 QuickTime Video
An Origin of Species  

An Origin of Species
In this Evolution Web feature, witness for yourself how a new species can evolve as you observe natural selection and adaptive radiation in action.

9-12 Flash Interactive
Origins of Humankind  

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

9-12 Flash Interactive
Pearl and Hermes Atoll  

Pearl and Hermes Atoll
This video segment adapted from the NOW-RAMP 2002 Expedition documents a research expedition to Pearl and Hermes Atoll in Hawai`i. Watch as biologists assess the bird and plant populations and then work to eradicate invasive species.

5-12 QuickTime Video
Penguin Response to Climate Change  

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.

6-12 QuickTime Video
Plants-in-Motion  

Plants-in-Motion
While we tend to think of plants as stationary, they are in constant, though very slow motion, as they respond to environmental factors. Watch plants move in time-lapse videos in this interactive activity adapted from Indiana University.

K-12 Flash Interactive
Polar Bears and Climate Change  

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.

6-12 QuickTime Video
The Powerhouse of the Cell  

The Powerhouse of the Cell
This video segment describes the critical role that mitochondria play in nearly every cellular process in your body.

9-12 QuickTime Video
Preimplantation Genetic Diagnosis  

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.

9-12 QuickTime Video
Radiometric Dating  

Radiometric Dating
In this video segment from A Science Odyssey: "Origins," scientists explain how Earth's age was determined by radiometric dating.

6-12 QuickTime Video
Record of Time  

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

6-12 PDF Document
The Red Queen  

The Red Queen
An example of the Red Queen hypothesis, the sexual population of Mexican Poeciliid fish are able to keep up with a changing environment, while the asexual populations are not as successful. From Evolution: "Why Sex?"

6-12 QuickTime Video
Riddle of the Bones  

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.

9-12 Flash Interactive
RNAi Discovered  

RNAi Discovered
In this video segment adapted from NOVA scienceNOW, learn how RNAi, a mechanism that has evolved in cells to prevent viral infection, was discovered and how it works.

9-12 QuickTime Video
RNAi Explained  

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

9-12 Flash Interactive
RNAi Therapy  

RNAi Therapy
In this video segment adapted from NOVA scienceNOW, learn about RNAi's potential to treat a wide range of genetic and infectious diseases.

9-12 QuickTime Video
Sequence for Yourself  

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."

9-12 Flash Interactive
The Sequencing Race Begins  

The Sequencing Race Begins
This video segment from NOVA: "Cracking the Code of Life" looks at one of the key players in the race to decode the human genome.

9-12 QuickTime Video
Sex and the Single Guppy  

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.

6-12 Shockwave Interactive
Shape of Trees: The Frustration Principle  

Shape of Trees: The Frustration Principle
This series of images shows the work of biologist Karl Niklas on the adaptations and evolution of plants. From The Evolutionary Biology of Plants.

9-12 JPEG Image
Should We Create Babies by Design?  

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

9-12 HTML Interactive
Should We Grow GM Crops?  

Should We Grow GM Crops?
Learn the pros and cons of genetically modified (GM) crops, and cast your vote on whether they should be grown. From the FRONTLINE/NOVA: "Harvest of Fear" Web site.

9-12 HTML Interactive
Simple Solutions  

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.

3-12 QuickTime Video
Snapshot of U.S. Energy Use  

Snapshot of U.S. Energy Use
This video segment adapted from NOVA/FRONTLINE looks at American energy consumption and the resulting production of greenhouse gases.

3-12 QuickTime Video
Stem Cells Breakthrough  

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.

9-12 QuickTime Video
Stem Cells: Seeds of Hope?  

Stem Cells: Seeds of Hope?
This video explores the basic scientific and ethical questions surrounding the use of stem cells in medical research.

9-12 QuickTime Video
Stories in the Ice  

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

9-12 HTML Document
Super Salmon  

Super Salmon
This video segment from FRONTLINE/NOVA: "Harvest of Fear" explores genetic modification of salmon and possible consequences.

9-12 QuickTime Video
Sweaty T-shirts and Human Mate Choice  

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.

9-12 QuickTime Video
Taking the Earth's Temperature  

Taking the Earth's Temperature
This video segment from FRONTLINE/NOVA: "What's Up with the Weather?" depicts research efforts to record Earth's past and present temperatures shifts.

9-12 QuickTime Video
Tale of the Peacock  

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

6-12 QuickTime Video
Ted Daeschler and Neil Shubin: Early Tetrapod Fossils  

Ted Daeschler and Neil Shubin: Early Tetrapod Fossils
In this transcript of an interview filmed for Evolution: "Great Transformations," Ted Daeschler and Neil Shubin describe the discovery and significance of some of their key fossil finds.

9-12 HTML Document
Three Ways to Check a Fetus's Chromosomes  

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.

9-12 JPEG Image
Toxic Newts  

Toxic Newts
The father and son team of Brodie and Brodie track down the predator able to stomach a mysteriously hyper-toxic newt, an example of an evolutionary arms race in action. From Evolution: "Evolutionary Arms Race."

6-12 QuickTime Video
Tracing Human Evolution to Its Roots  

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.

9-12 JPEG Image
The Transforming Leap, from Four Legs to Two  

The Transforming Leap, from Four Legs to Two
John Noble Wilford, a New York Times science writer, outlines various hypotheses on the origin of bipedalism.

9-12 HTML Document
Transitional Tetrapod Fossil  

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.

6-12 QuickTime Video
Trying to Breathe on Mount Everest  

Trying to Breathe on Mount Everest
In this video segment adapted from NOVA, climbers attempting to reach Mount Everest's summit must contend with the low levels of oxygen at high altitudes.

6-12 QuickTime Video
Types of Fossils  

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.

3-12 Flash Interactive
Understanding Gene Testing  

Understanding Gene Testing
In this article by the National Cancer Institute and the National Center for Human Genome Research, find answers to your questions about genetic testing.

9-12 PDF Document
The Value of Wetlands  

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.

4-10 QuickTime Video
Viewpoints: Harvest of Fear  

Viewpoints: Harvest of Fear
What do the experts say about genetically modified (GM) foods? Read these interview excerpts from the FRONTLINE/NOVA: "Harvest of Fear" Web site to find out.

9-12 HTML Document
Walking Tall  

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).

9-12 QuickTime Video
The Wall of Time  

The Wall of Time
This illustrated timeline from the Lunar and Planetary Institute provides a journey through four-and-a-half billion years of time from the birth of our solar system to its current existence today.

6-12 JPEG Image
Whales in the Making  

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

6-12 PDF Document
What Is a Theory?  

What Is a Theory?
In these two audio interviews from NOVA Online, learn about the difference between the common understanding of the word "theory" and how science uses the term.

6-12 Flash Interactive
What Killed the Dinosaurs?  

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.

6-8 Shockwave Interactive
Who Owns the Genome?  

Who Owns the Genome?
This video segment from NOVA: "Cracking the Code of Life" examines the social and ethical implications of genome research.

9-12 QuickTime Video
Wild Animal Rehabilitation  

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.

3-12 QuickTime Video
Your Carbon Diet  

Your Carbon Diet
Find out how much energy you use and common sense ways to conserve. From the FRONTLINE/NOVA Web site "What's Up with the Weather?"

9-12 Shockwave Interactive