The concept of competitive exclusion, explained here, states that two species cannot co-exist when needing the same, limited resources to survive. The different types are described and examples are provided.

Dive in and explore what makes this beautiful world so fragile. In this Web feature, from the PBS series "Evolution," discover how coevolution has shaped the ecological relationships among reef creatures.

This site from the Canadian Museum of Nature, a natural history museum, provides short information blurbs and fun facts on over 240 different common animals categorized by type (mammals, fish, reptiles, invertebrates, amphibians,...

Find out about the plant and animal interactions within the rainforest ecosystem.

Interspecific competition in an ecosystem is explained, along with the different ways it can manifest itself. Includes examples in different types of biomes.

Learn how mutualism benefits the organisms in a symbiotic relationship and what the different types of mutualism are. Provides lots of examples.

[Free Registration/Login may be required to access all resource tools.] Summarizes the key points about the evolution of agriculture and how it has impacted human population growth. Includes a few questions to check for understanding.

Species interact every day. That interaction is a vital part of how organisms develop and change over time. When you study species, it is important to watch the way they interact with their surroundings. There are four basic types of...

Describes the role of mutualism in an ecosystem and the different types, and provides examples.

Explains what parasitism is and provides a few examples of parasitic relationships.

Interactive zoo site features the Komodo Dragon. Users are invited to discover more about this fascinating creature as they peruse this site. Users may test their knowledge by playing an interactive quiz game, view photos and video, as...

A look at what fossil evidence reveals about the life and ecological interactions of this extinct species of a clam.