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Unifying Life Site: Placing Urban Tree Diversity in an Evolutionary Context

School of Education

Unifying Life Site: Placing Urban Tree Diversity in an Evolutionary Context

Welcome to Unifying Life, a curriculum to help middle school students learn about the street trees that they see daily. Kids walk by trees and other plants every day and many cannot identify a maple or an oak. This curriculum uses Leafsnap (, a cutting edge iPhone tree identification app to help students through careful observation:

  1. Notice and identify local trees.
  2. Group local trees into groups based on relatedness.
  3. Understand that related individuals in a group are similar because they share characteristics that are a result of common ancestry or shared evolutionary history.
  4. Understand evolutionary constraint, meaning that organisms cannot change characteristics based simply on need.
  5. Learn that most street trees have flowers and fruits, even if they do not notice them and that street tree fruits are fruits, just like the fruits students eat at home.
  6. Learn that flowers become fruits and that they are reproductive structures for fertilization and seed dispersal.

To match the life cycle of local trees, the curriculum is divided into sections, the fall and spring, each lasting about two weeks. The fall curriculum focuses on identification, grouping, common ancestry and fruits. The spring curriculum focuses on grouping, common ancestry, and flowers. 

Curriculum Guide, Fall and Spring Curriculum Components

If you do not have access to the Leafsnap app, you can still use this curriculum, but you will need to use a traditional field guide. The curriculum is designed for use in the regions of North America with deciduous trees. 

This work was funded by NSF grant # 1221188. Any opinions are those of the authors and not of the NSF. 


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Paradise apple (Malus pumila) flower

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Paperbark maple (Acer griseum) leaf

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Students identifying street trees with the Leafsnap app

"But we walked all the way down the street talking about the trees and Leafsnapping them, and then on the way back, I could point to one and they would yell out the name so proud that they knew—they could recognize something. And yeah —it was a great moment in sixth grade, just the enthusiasm that they showed that they had never shown towards trees probably in their whole life. Now suddenly, they're noticing them."

Statement from a 6th grade teacher

About Us

A team headed by Professor Yael Wyner in Secondary Education at the City College of New York, part of the City University of New York and Dr. Janice Koch (Professor Emerita Hofstra University) developed this curriculum. Team members include Jessica Genter and Renee Thorne, now middle and high school teachers in New York City and Sarah Seiter, now Associate Curator of Natural Sciences at the Oakland Museum.  In addition, we made changes to the curriculum based on insights from student assessments that were part of a study on the curriculum conducted by Dr. Wyner and Dr. Jennifer Doherty from the University of Washington in Seattle. Finally, the curriculum would not be in its present form without the help of the fifteen middle school teachers who tested the curriculum in their classrooms. They provided valuable suggestions and modifications that are incorporated into the final curricular product.