Life is ubiquitous on Earth and appears in a diversity of forms. But what characteristics do organisms have? What makes them alive? This activity explores that question. In the first part of the ...

All life on Earth shares a common ancestor that lived roughly four billion years ago. This so-called “last universal common ancestor” represents the most ancient organism that researchers can study.

To enhance students’ engagement with and deepen their understanding of the concept of life, consider pairing this narrative with the following classroom resources: The HHMI BioInteractive activity ...