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.

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.

This annotated slideshow adapted from KET's Electronic Field Trip to the Forest illustrates how blight decimated the American chestnut tree and the methods scientists use to identify and pollinate the remaining trees to create blight-resistant trees.

This lesson will introduce camouflage and adaptations, enabling students to be able to identify the importance of animals adapting in a changing climate. 

Using the Hardy-Weinberg equation to calculate allele and genotype frequencies. Created by Sal Khan.

The next time you are in the kitchen, try this experiment: pick up a box of butter (four sticks) in one hand and a box of saltines (four packets) in the other. Which is heavier? If you said the butter, you are not alone. Most people would identify the box of butter as the heavier object even though, if you look at the labels, you'll see that they both weigh exactly one pound! This is an example of the size-weight illusion, and it is incredibly common. Read more to see the evolution (and baseball) connection ...

Hunt for prey and discover the meaning of evolutionary “fitness” in this physically active group game. In this simulation game, teams of predators equipped with genetically different “mouths” (utensils) hunt for “prey” (assorted beans). Over several “generations” of play, the fittest among the predators and prey dominate the population, modeling the evolutionary process of natural selection.

Students toss coins to determine what traits a set of mouse parents possess, such as fur color, body size, heat tolerance, and running speed. Then they use coin tossing to determine the traits a mouse pup born to these parents possesses. Then they compare these physical features to features that would be most adaptive in several different environmental conditions. Finally, students consider what would happen to the mouse offspring if those environmental conditions were to change: which mice would be most likely to survive and produce the next generation?

Patterns and processes of evolution. How evolution and natural selection are reflected in the similarities and differences of organisms.

Biology is designed for multi-semester biology courses for science majors. It is grounded on an evolutionary basis and includes exciting features that highlight careers in the biological sciences and everyday applications of the concepts at hand. To meet the needs of today’s instructors and students, some content has been strategically condensed while maintaining the overall scope and coverage of traditional texts for this course. Instructors can customize the book, adapting it to the approach that works best in their classroom. Biology also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand—and apply—key concepts.

By the end of this section, you will be able to:Describe how the present-day theory of evolution was developedDefine adaptationExplain convergent and divergent evolutionDescribe homologous and vestigial structuresDiscuss misconceptions about the theory of evolution

By the end of this section, you will be able to:Explain the different ways natural selection can shape populationsDescribe how these different forces can lead to different outcomes in terms of the population variation

By the end of this section, you will be able to:Define population genetics and describe how population genetics is used in the study of the evolution of populationsDefine the Hardy-Weinberg principle and discuss its importance

By the end of this section, you will be able to:Describe the different types of variation in a populationExplain why only heritable variation can be acted upon by natural selectionDescribe genetic drift and the bottleneck effectExplain how each evolutionary force can influence the allele frequencies of a population

In this interactive activity from Shedd Aquarium, build a fish and then release it into the reef to search for food and evade predators. Try different combinations and observe how each kind of fish has unique adaptations that help it survive in its habitat.

In this video segment from NatureScene, explore Cartwheel Bay, a wetland in South Carolina, and learn about the variety of carnivorous plants native to this unique landform.

Explore how populations change over time in a NetLogo model of sheep and grass. Experiment with the initial number of sheep, the sheep birthrate, the amount of energy sheep gain from the grass, and the rate at which the grass re-grows. Remove sheep that have a particular trait (better teeth) from the population, then watch what happens to the sheep teeth trait in the population as a whole. Consider conflicting selection pressures to make predictions about other instances of natural selection.