Professors create website for history of Earth, evolution

The website compiles information from more than 3,000 studies into a public database.

Blair Hedges and Sudhir Kumar, both biology professors, work at the Center for Biodiversity and developed a map to visualize Earth’s history. GENEVA HEFFERNAN | ASST. PHOTO EDITOR

Blair Hedges can name species that lived more than 50 million years ago by clicking on a website he helped create.

Biology professors Sudhir Kumar and Hedges co-direct TimeTree, an interactive website that allows users to discover species divergence, or when a species splits into two. The pair are both Laura H. Carnell professors, which recognizes stand-out educators and researchers,  in the College of Science and Technology.

This project is part of the Center for Biodiversity, which focuses on evolution under Hedges’ direction.

The website also allows users to build a time tree, which is an evolutionary tree of life chart that also looks at the evolutionary history of a species, family or class. TimeTree takes data from more than 3,000 academic articles and compiles them into a public knowledge database on the tree of life, a research tool used to understand the evolution of life and describe the relationships between organisms. The website also shows the evolutionary timescale for more than 97,000 species.

“[TimeTree] not only tells you about the evolutionary history of the relationship of species, but also when they came about,” Kumar said. “That is exactly what TimeTree is about and we can add bells and whistles and new tools to it, but ultimately the basic concept of that particular resource is TimeTree.”

TimeTree came to fruition in the late 1990s, when Hedges and Kumar were Ph.D. students at Pennsylvania State University and Hedges earned a grant from NASA.

“It was the beginning of the astrobiology institute that NASA has, and we proposed this database and they liked the idea and funded it,” Hedges said.

Kumar said when the first version of the TimeTree website was released in 2006, there were only a few thousand species and a few hundred studies contained.

“TimeTree’s [purpose] is to give people information on the timescale of the evolution of life,” Hedges said. “Family trees, like the family trees for people or species, are really how things are related, but it’s not necessarily a time scale. It uses relationships we have, and then it adds the other dimension of time.”

Kumar said the most interesting aspect of TimeTree is the challenge of how to accurately represent knowledge from a large number of studies in a single picture.

Hedges works on the design of the database and checks the quality of the data.

Sarah Hanson, a full-time research assistant in Center for Biodiversity, has worked on TimeTree since 2012 and is a data curator for the website. She also earned her master’s in globalization and development communication in 2016.

“It’s my job to identify studies that are useful for TimeTree,” Hanson said. “It’s also my job to contact the authors to ask for their data files and organize and prepare the data to be entered into the database.”

In the future, Hedges hopes the website will continue to expand and develop new tools, like adding more abiological features and making navigation on the site easier.

“Most importantly, we want to keep up with the progress of science,” Hedges said. “It takes a lot of work to do that, and at the moment, Sarah has 1,000 new studies to add to the database.”

Moriah Thoman can be reached at

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