Adaptive Radiation: Darwin's Finches

Finches on the Galapagos Islands have evolved to exploit almost every possible niche. This diagram shows the range of food sources available on the island and the different beak shapes adapted to exploit each of them.

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.

Animal and Plant Cell

Think you can tell a yam from a yak? Examine these still images of typical plant and animal cells from Biology by Kenneth R. Miller and Joseph Levine. What similarities and differences can you find?

Animal Babies

This interactive slide show illustrates the variety of animal babies that exist on earth -- some completely independent and others deeply reliant on parental care.

Animal Coverings

It takes a thick skin to withstand the hardships that life has to offer. This collection of images shows a variety of animals, each with a slightly different type of protective covering.

Animal Mouths

This collection of images of six different creatures, including insects and carnivorous vertebrates, illustrates the wide range of mouth types that exist within the animal kingdom.

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Bird Beak Gallery

This collection of images of 10 different birds illustrates the diversity of bird beaks.

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Bird Food

There are almost as many types of bird beaks as there are types of food that birds like to eat. This collection of images shows a wide range of beaks and the types of foods handled by each.

Carbon Cycle Diagram

This diagram from NASA's Earth Science Enterprise illustrates the Earth's carbon cycle .

Colorful Creatures

For animals, bright, flashy coloration can serve as a warning or as an invitation. Either way, colorful skin, feathers, and scales yell, "Notice me!" This collection of images shows examples of some of the world's most colorful creatures.

Duckweed

These images of duckweed (Lemna spp.) illustrate the basic anatomy and environment of these fast-growing plants.

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.

Function of Fever

Fevers are a sign of infection, but they may also be part of the cure. This drawing illustrates Matthew Kluger's lizard study, which supports the notion that fever can be beneficial.

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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.

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.

Growing Up, Growing Old

This collection of six images captures the magnificence of human development -- the transformation from baby to woman.

How the Woodpecker Avoids a Headache

This diagram from Rainbird Publishing describes the specialized physical characteristics that allow woodpeckers to create some of the most secure nests in the bird world.

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Inside a Seed

This image from Biology by Kenneth R. Miller and Joseph Levine illustrates the five most important parts of a seed: the seed coat, the endosperm, and the embryo's primary root, cotyledon, and embryonic leaves.

Jaws and Teeth of Mammals

This image from Biology by Kenneth R. Miller and Joseph Levine illustrates the relationship between structure and function by comparing the jaws and teeth of two animals with very different ways of life: the wolf and the horse.

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.

Laetoli Trackways Diagram

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

Living and Nonliving

What is it that distinguishes a living organism from a nonliving object? This collection of images presents examples that aren't as clear-cut as one might think, enticing students to question the meaning of life.

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.

Seeds Away

This collection of images shows several types of plant seeds, each with a different mechanism for dispersing from the parent plant.

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.

Sickle vs. Normal Cell

Background image of normal disc-shaped red blood cells from the University of Utah. Inset shows sickled red blood cells, curved and rigid, from the Virginia Medical College.

Tetrapod Limbs

This illustration from Evolution by Monroe W. Strickberger shows the remarkable similarities between the bones in the forelimbs of various tetrapods, all of whose limbs serve very different functions.

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