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The Hawaiian Bobtail squid has a remarkable symbiotic relationship with a species of marine bacteria that can produce light by a controlled chemical reaction. Also featured on the HHMI DVD, Exploring Biodiversity: The Search for New Medicines, available free from HHMI.

Components of the immune system called antibodies are found in the liquid portion of blood and help protect the body from harm. Antibodies can also be used outside the body in a laboratory-based assay to help diagnose disease caused by malfunctions of the immune system or by infections.

Transgenic organisms, which contain DNA that is inserted experimentally, are used to study many biological processes. In this lab, you will create a transgenic fly to study circadian rhythms.

This activity supports the HHMI short film The Origin of Species: The Making of a Theory. Students are presented with a map of the Malay Archipelago and some field notebooks with observations of animals. By plotting which animals are found on which island, the students discover the Wallace Line-a sharp boundary that separates distinct Asian and Australian fauna. 

The anole lizards of the Caribbean islands represent a group of about 150 closely related species, most of which evolved within the past 50 million years from a single colonizing species. Different processes, including geographic isolation, adaptation to different environments, and reproductive isolation, play a role in anole speciation. 

1 minute animated video

Are we witnessing a sixth mass extinction? What factors threaten ecosystems on land and in the sea? What are researchers doing to try to conserve biodiversity and ecosystems such as tigers in Asia and coral reefs around the world? What tools do we have to avoid a global catastrophe? In six half-hour lectures, three leading scientists describe the state of biodiversity on our planet and how to face the great challenges that lie ahead.

Corn was originally bred from the teosinte plant by native Mexican farmers. The morphologies of modern-day corn and teosinte plants are compared to illustrate how artificial selection can bring about dramatic changes in plants.

18 min video- Ten thousand years ago, corn didn't exist anywhere in the world, and until recently scientists argued vehemently about its origins. Today the crop is consumed voraciously by us, by our livestock, and as a major part of processed foods. So where did it come from? Popped Secret: The Mysterious Origin of Corn tells the story of the genetic changes involved in the transformation of a wild grass called teosinte into corn.  Evidence from genetics supports archeological findings pinpointing corn's origins to a very particular time and place in Mexico

Comparing features of a 4.4-million-year-old fossil skeleton to those of human and chimpanzee skeletons sheds light on our evolutionary history.

"Survival of the Fittest: Variations in the Clam Species Clamys sweetus" is a guided inquiry. This series of hands-on activities complements the HHMI DVD Evolution: Constant Change and Common Threads and requires simple materials such as M&Ms, Reese's Pieces, food storage bags, and paper cups. This activity has been designed to engage students in thinking about the mechanism of natural selection by encouraging them to formulate questions that can be answered through scientific investigation, data collection, and pattern recognition.

Taxonomy groups species by common traits. Modern taxonomy emphasizes evolutionary relatedness. Explore some principles of taxonomy by sorting twenty shells by their morphological characteristics. Whenever a pictorial index of shells appears, you can click on an image of a shell to open it in a separate window. There you can click and drag your mouse over the shell to rotate it for a more detailed examination. Additionally, you can use the small buttons in the lower right corner of the window to rotate the shell.

background for cone snail click and learn

The seashell phylogeny and evolution activity is an interactive online activity that can be done in class or assigned as homework. The Teacher's Guide describes supporting resources that can be used to teach students about seashells and a pre-activity exercise that uses the downloadable picture cards to familiarize students with the concept of sorting organisms.

31min video  The epic voyages of Darwin and Wallace led each to independently discover the natural origin of species and to formulate the theory of evolution by natural selection.

This interactive explores different anatomical features of the human body and what they reveal about the evolutionary history we share with other organisms, including earlier, long-extinct species.

The virtual lab includes four modules that investigate different concepts in evolutionary biology, including adaptation, convergent evolution, phylogenetic analysis, reproductive isolation, and speciation. Each module involves data collection, calculations, analysis and answering questions. The "Educators" tab includes lists of key concepts and learning objectives and detailed suggestions for incorporating the lab in your instruction.

The Y chromosome is only one-third the size of the X. Although the Y has a partner in X, only the tips of these chromosomes are able to recombine. Thus, most of the Y chromosome is inherited from father to son in a pattern resembling asexual, not sexual, reproduction. No recombination means no reassortment, so deleterious mutations have no opportunity to be independently selected against. The Y chromosome therefore tends to accumulate changes and deletions faster than the X. Degradation doesn't occur in X chromosomes because during female meiosis, the X has the other X as a full partner in recombination.

The many forms of dogs that exist today were all created through selective breeding from the dog's ancestor, the wolf. In a span of less than 10,000 years, breeders have changed traits and body shapes of dogs by artificial selection-for example, emphasizing different aspects of hunting and herding behavior.

This Click and Learn explains how DNA sequences can be used to generate such trees, and how to interpret them.