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You might be surprised to learn that descendents of an ancient bacterium are living in every cell of your body! Find out how endosymbiosis factored into the evolution of your own cells and learn about a modern example of this process.
UC Museum of Paleontology
Additional in-class discussion may enhance student learning based upon this article. Key questions at the beginning of the article could be used to stimulate discussion.
Correspondence to the Next Generation Science Standards is indicated in parentheses after each relevant concept. See our conceptual framework for details.
- Biological evolution accounts for diversity over long periods of time. (LS4.A, LS4.D)
- Through billions of years of evolution, life forms have continued to diversify in a branching pattern, from single-celled ancestors to the diversity of life on Earth today.
- Present-day species evolved from earlier species; the relatedness of organisms is the result of common ancestry. (LS4.A)
- Life on Earth 3.8 billion years ago consisted of one-celled organisms similar to present-day bacteria.
- The early evolutionary process of eukaryotes included the merging of prokaryote cells.
- There are similarities in the cell function of all organisms. (LS4.A)
- Scientists can test ideas about events and processes long past, very distant, and not directly observable.
- Our knowledge of the evolution of living things is always being refined as we gather more evidence.
- Our understanding of life through time is based upon multiple lines of evidence.