Neurons in the cortical area 5 are active when a cat is straddling an obstacle.
This animation series shows four experiments that compare the activity patterns of a wild-type fly keeping a normal schedule with those of a mutant fly apparently following a 19-hour internal clock.
Demonstrates how changes in the amount of fat tissue lead to changes in leptin levels and thus changes in appetite.
A touch to the Aplysia's siphon causes a gill withdrawal, a simple reflex for studying memory.
The bobtail squid swims during the night to hunt. During the day, it burrows to hide from predators.
Even when distracted by food, the cat's brain encodes and retains the location of an obstacle.
Video microscopy of mating between a male and a hermaphrodite C. elegans roundworm.
Dr. Zoghbi introduces the topic of Rett syndrome by showing how development usually progresses in a young girl. She then shows an excerpt from ...
Dr. Jessell's leg muscle activation patterns are recorded during walking.
This species of cone snail immobilizes its prey in a split second with lightning-strike cabal toxins.
A fish-hunting cone snail strikes its prey with a venomous harpoon, causes paralysis, and eats it.
Larger cone snails produce more venom and are more dangerous to human beings in an accidental stinging.
A worm-hunting cone snail species feeds on fireworms, and is unaffected by the prey's sharp bristles.
A species of fish-hunting cone snail quickly immobilizes its prey and swallows it.
Fossilized dung beetle balls are part of a comprehensive fossil collection project to reconstruct the habitat of Ardipithecus ramidus.
Male courtship dances in two fruit fly species show that the wing spots play a prominent role.
Chimpanzees are capable of using rocks as tools to crack nuts for eating. But they don't appear to use sharp-edged tools.
Mice can be trained to use spatial cues to navigate a maze that tests their ability to remember specific locations.
Dr. Evans compares the activity of a normal mouse to one with a mutation in a key gene controlling obesity.
To prevent mosquitoes from spreading diseases, it's essential to understand their life cycle.
Dr. Ronald Evans discusses the so-called "marathon" mouse, with a mutation in the PPAR-gamma gene, and its performance on a treadmill relative to a normal mouse.
At the end of the ice age, the retreating ice sheet created many new lakes, some of which were colonized by sticklebacks.
This time-lapse videoclip shows human circadian activity while assembling a T. rex skeleton.
This time-lapse videoclip illustrates a mouse's nocturnal behavior.
Dr. Jason Biggs of the University of Guam Marine Laboratory discusses the anatomy of cone snails and introduces us to a variety of cone snail species with different tactics to hunt and capture their prey.
Dr. Harshad Vishwasrao guides you through a collection of images showing neuronal growth and synaptic formation representative of anatomical changes that occur during learning.
Venomous carniverous cone snails are a rich source of molecules for scientific research and potential drug development.
In this ten-minute Q&A session, Dr. Olivera answers questions on cone snail behavior, venoms, and biodiversity.
What is mind? Can molecular biology help us understand mental function?
The history of localization of function in the brain, and research that led to the understanding of localization of memory.
Understanding the neural circuits in the spinal cord that control movement.
The cellular and molecular nature of learning and memory, investigated in simpler sea slugs and more-complex mice.
In the 2004 Holiday Lectures on Science, HHMI investigators Ronald M. Evans and Jeffrey M. Friedman discuss how the body regulates weight by carefully controlling the storage and burning of fat—and how a better understanding of these complex metabolic systems could lead researchers to...
Dr. Friedman introduces the genes and circuits that control appetite, including the key role of leptin.
Dr. Evans describes how fat communicates with muscle and how diet and exercise influence that relationship.
Four lectures highlight the research of two scientists who have made groundbreaking discoveries elucidating the molecular basis of circadian clocks—the internal timekeepers that govern fluctuations in behavior and physiology on a 24-hour cycle.
Dr. Joseph Takahashi takes us on an exciting journey into a very special region of the brain—the biological clock that governs our physiology and certain behaviors.
Although tiny in size, the fruit fly has had a major impact on our understanding of circadian rhythms.
This survey, developed by Horne and Ostberg, will let you determine if you are a morning or an evening person.
Explore the biology of the symbiotic relationship between the Hawaiian Bobtail squid and bioluminescent bacteria Vibrio fischeri.
Different gaits employed by animals and how the nervous system is able to switch between them.
To accompany the lecture series Viral Outbreak: The Science of Emerging Disease.
To accompany the lecture series AIDS: Evolution of an Epidemic. In this activity, you simulate taking HIV antiretroviral drugs by using tic tac mints and Kool-Aid packets.
This activity uses the planaria's property for regeneration and compares how long it takes for planaria cut in different places to regenerate a head.
In this activity, students rear mosquitoes in chambers and test variables that might affect the life cycle of the mosquito.
Finches discriminate between members of their own species and those of a closely related species based on song and appearance.
The following classroom-ready resources complement The Origin of Species: The Beak of the Finch. By following four decades of research on the finches of the Galápagos islands, the film illustrates how geography and ecology can drive the evolution of new species.
The following classroom-ready resources complement The Origin of Species: Lizards in an Evolutionary Tree. Research on the anole lizards is enriching our understanding of evolutionary processes, such as adaptation by natural selection, convergent evolution, and the formation of new...
This animation features the anole lizards as an example of how a single species can split and multiply into many different species with distinct traits.
Dr. Elinor Karlsson discusses her work with dogs as a model organism for genomic studies.
The fins of the scalyhead sculpin are related to our arms.
This classroom experiment supports the film The Origin of Species: The Beak of the Finch. Students collect and analyze data to learn why even slight variations in beak size can make the difference between life and death.
The shape of our hands comes from tree-dwelling ancestors.
Female peacock spiders stay with their young in an egg sac until they can fend for themselves.
Infant lemurs hitch a ride through the forest by holding on to their mother’s tummy or riding piggyback.
The male peacock spider performs a spectacular dance to attract a mate—but the female is not always impressed.
The Lizard Evolution Virtual Lab was developed by a team of scientists, educators, graphic artists, and film makers to explore the evolution of the anole lizards in the Caribbean.
The richness and diversity of life raises two of the most profound questions in biology: How do new species form? And, why are there so many species?
In the Caribbean islands, adaptation to several common habitats has led to a large adaptive radiation with interesting examples of convergent evolution.
Four decades of research on finch species that live only on the Galápagos Islands illuminate how species form and multiply.
This activity supports the film The Origin of Species: Lizards in an Evolutionary Tree. Students are guided to sort the lizard species by appearance, then generate a phylogenetic tree using the lizards’ DNA sequences to evaluate whether species that appear similar are closely related...
Weaver ants labor to carry a live land snail back to their nest in Gorongosa National Park.