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. [4:59]

Article examines the factors that drove forward the expansion of the British Empire during the nineteenth century and asks whether it was desire for trade or "thirst of conquest." Archived.

Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Discuss the predator-prey cycle
Give examples of defenses against predation and herbivory
Describe the competitive exclusion principle
Give examples of symbiotic relationships between species
Describe community structure and succession

Let's explore Earth with a microscope! Dive deep down into the diverse world of microbes with our scientists from the Joint Genome Institute. We'll also hear from students about their experiences taking part in environmental research and internships.

This article discusses the many lichens found in the Arctic and Antarctica and their unique characteristics.

Learn about the endosymbiotic theory. This theory explains the evolution of cells from a mitochondria and chloroplast working together in a symbiotic relationship to the current cell structure.

Travel underground for an up-close look at the ants, amoebas, and bacteria that maintain healthy soil. Glimpse this microscopic world and learn about the symbiotic relationship between fungi and tree roots. [2:49] Support materials for students is provided.

Explore the relationship between buffalo and wolves in the North American plains with this wildlife video! Join filmaker Jeff Turner as he follows one pack of wolves observing how they live together with the buffalo. [53:10]

Question and answer site that contains a discussion of commensalism as it pertains to sea slugs. Nice photographs of aquatic commensalistic relationships.

In this video segment from Nature, see the value that sharks can have on the tourism industry in an area.

In this video segment from Nature, see the value that sharks can have on the tourism industry in an area. [1:41]

This lesson will introduce the three types of symbiotic relationships and give examples of each. It is 4 of 4 in the series titled "Symbiotic Relationships."

Adam Jacobson explains endosymbiosis, a type of symbiosis in which one symbiotic organism lives inside another. [5:42]

Video explores the interdependence of two species to define the concept of symbiosis. [2:23] Followed by a short quiz and a list of additional resources to explore.

A variety of symbiotic relationships exist between sharks and other marine species in this segment from Nature. [2:03]

A variety of symbiotic relationships exist between sharks and other marine species in this segment from Nature.