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Science Journey: The Origin of Photosynthesis: A Window into the Intricate Relationship Between Life and the World Around It

The origin of oxygenic photosynthesis, about 2.4 billion years ago, dramatically transformed the face of our planet and redirected the course of life's evolution. Using the different scientific perspectives offered by geology, biology, and chemistry, scientists pieced together different parts of the story concerning this crucial turning point in the history of life on Earth. For example, scientists deciphered the clues preserved in sedimentary rocks to learn about past environments and investigated the workings of modern microbes to learn about their ancient ancestors. By approaching this problem from many different perspectives (that of a geologist, biologist, chemist, and even artist) scientists were able to discover unexpected and important connections that would not have been accessible from one perspective alone.

About the Speaker

Usha Lingappa grew up in San Francisco. She wanted to be an artist and attended Hampshire College planning to study art. Instead, she got distracted by science. After finishing college, she spent several years hunting aliens and viruses (astrobiology research at NASA and antiviral research at a biotech company) before pursuing her PhD in geobiology at Caltech. Her PhD research focused on the origin of photosynthesis – a pivotal transition in the history of life on Earth. In addition to her science work, she continues to maintain an art practice. She likes the way her art and her science influence each other, and both inform how she understands the world around her.

About the Series

Science Journeys online programs are recommended for grades 8 and up, but everyone is welcome to attend.

These programs are made possible through the generosity of the Friends of Beckman Auditorium.

If you have questions, please email Mary Herrera at

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