Scientists believe that life on Earth has changed over time, and that it is still changing. In this module, you will explore the theory of evolution, which is the concept that the organisms on Earth today developed and changed from organisms present in earlier time periods. You will begin by learning how the fossil record supports the idea that life originated in Earth's oceans and moved to land. In addition, you will examine the process of natural selection, which explains how species – including humans – adapt to constant changes in their environments.

Getting Started

Before you begin learning about evolution and the role that natural selection plays in life on Earth, see how many of the related terms and definitions you understand. In this non-graded activity, read the definition, and then drag and drop the term into the blank space provided. Then, click SUBMIT to check your responses. Click the player button to get started.

 

 

Key Vocabulary

To view the definitions for these key vocabulary terms, visit the course glossary.

adaptation	evolution	natural selection
adaptive radiation	extinction	punctuated equilibrium
analogous structure	fossil record	radiocarbon dating
bottleneck effect	founder effect	relative dating
coevolution	gene flow	reproductive isolation
convergent evolution	genetic drift	speciation
directional selection	genetic variation	stabilizing selection
disruptive selection	homologous structure	trace fossil
divergent evolution	index fossil	vestigial structures
embryology	mass extinction