60-Second Science: Phylogenetic Trees

PHOTO: Dr. Evelyn Williams, Conservation Scientist.Dr. Evelyn Williams is an adjunct conservation scientist at the Garden. She’s interested in genetic diversity at multiple scales, from the population to the family level. While at the Garden, Dr. Williams has worked on rare shrubs from New Mexico (Lepidospartum burgessii), systematics of the breadfruit family (Artocarpus), and using phylogenetic diversity to improve tallgrass prairie restorations.


When a scientist says that chimpanzees are related to humans, or that chickens are related to dinosaurs, what do they mean?

They mean that chimpanzees and humans share a common ancestor from many thousands of generations ago. Although that shared great-great-great-great-(etc.)-great-parent lived many years ago, that shared ancestor lived more recently than the ancestor that humans share with dogs. So humans are more closely related to chimpanzees than dogs because they have the most recently shared ancestor. Scientists call this the “most recent common ancestor.”

This most recent common ancestor wasn’t a chimp, and it wasn’t a human—it was a different species with its own appearance, habits, and populations. One of these populations evolved into humans, and one of the populations evolved into chimpanzees. We know this because of a field of study called “phylogenetics.” Scientists use phylogenetics to study how species are related to each other. 

Phylogenetic tree diagram.

Using DNA sequences, scientists construct tree-like diagrams that trace how species are related. A human’s DNA is more similar to a chimpanzees’ than to a chicken, so a tree diagram would connect humans and apes. Dinosaurs and chickens would be shown as related as well, and then these two groups would be connected.

Interested in learning more? Explore phylogenetics with the Tree of Life Web Project. Dig deep into the study of the phylogenetic roots of food plants with The Botanist in the Kitchen


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This is our fourth installment of their exploration.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

60-Second Science: Plants’ Roots Helped Them Move to Land

PHOTO: Alicia Foxx.Alicia Foxx is a second-year Ph.D., student in the joint program in Plant Biology and Conservation between Northwestern University and the Chicago Botanic Garden. Her research focuses on restoration of native plants in the Colorado Plateau, where invasive plants are present. Specifically, she studies how we can understand the root traits of these native plants, how those traits impact competition, and whether plant neighbors can remain together in the plant community at hand.


Life for plants on land is hard because the environment can become dry. Water is important because it is used when plants take in sunlight and carbon dioxide to make energy; this is called photosynthesis. In fact, the largest object in a plant cell is a sack that holds water. Without water, plants would die.

Plants first evolved in water, which is a comfortable place: there is little friction, you almost feel weightless, and…there was plenty of water back then. These plants had no difficulty photosynthesizing, as water diffused quite easily into their leaf cells! They had little use for roots.

Evolving Plant Structures

In the time plants evolved to live on land (100 million years later), water shortages and the need to be anchored in place became issues and restricted plants to living near bodies of water. Some plants evolved root-like structures that were mostly for anchoring a plant in place, but also took in some water.  

It wasn’t until an additional 50 million years after the move on to land that true roots evolved, and these are very effective at getting the resources essential for photosynthesis and survival. In fact, the evolution of true roots 400 million years ago is associated with the worldwide reductions in carbon dioxide, since more resources could be gathered by roots for photosynthesis. Importantly, plants were no longer tied to bodies of water!

PHOTO: tree roots.
Large roots anchor a plant in place.
PHOTO: bulb with tiny bulblets and root hairs.
Tiny root hairs on a bulb take up nutrients when moisture is present.

Water issues continued, however, even with true roots. Early roots were very thick and could not efficiently search through the soil for resources. So plants either evolved thinner roots, or formed beneficial associations with very tiny fungi (called mycorrhizal fungi) that live in the soil. These fungi create very thin, root-like structures that allow for more effective resource uptake. In general, while life on land is hard, plants have evolved ways to cope via their roots.

Garden scientists are studying the relationships between plants and mycorrhizal fungi in the soil. Orchids are masters of nutrient collection. The vanilla orchid has terrestrial (in soil) and epiphytic (above ground, or air) roots—and forms relationships with fungi for nutrient collection. Read more about research on Vanilla planifolia here


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This is our second installment of their exploration.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

60-Second Science: Dormancy and Germination

Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. Each week this spring, we’ll publish some of the results.

These brief explanations cover the topics of seed dormancy and germination, the role of fire in maintaining prairies, the evolution of roots, the Janzen-Connell model of tropical forest diversity, and more. Join us the next several weeks to see how our students met this challenge, and learn a bit of plant science too.


PHOTO: Alexandra Seglias at work in the field.Alexandra Seglias is a second-year master’s student in the Plant Biology and Conservation program at Northwestern University/The Chicago Botanic Garden. Her research focuses on the relationship between climate and dormancy and germination of Colorado Plateau native forb species. She hopes that the results of her research will help inform seed sourcing decisions in restoration projects.


PHOTO: A tiny oak sprouting from an acorn.
A tiny oak emerges from an acorn. Photo by Amphis (Own work) [CC BY-SA 3.0], via Wikimedia Commons


Dormancy and Germination

The seed is an essential life stage of a plant. Without seeds, flowers and trees would not exist. However, a seed doesn’t always live a nice, cozy life in the soil, and go on to produce a mature, healthy plant. Similar to Goldilocks, the conditions for growth of a seed should be “just right.” The charismatic acorn is just one type of seed, but it can be used here as an example. Mature acorns fall from the branches of a majestic oak and land on the ground below the mother tree. A thrifty squirrel may harvest one of these acorns and stash it away for safekeeping to eat as a snack at a later time. The squirrel, scatterbrained as he is, forgets many of his secret hiding places for his nuts, and the acorn has a chance at life. But it’s not quite smooth sailing from here for that little acorn.

Imagine trying to be your most productive in extreme drought, or during a blizzard. It would be impossible! Just as we have trouble in such inhospitable conditions, a seed also finds difficulty in remaining active, and as a result, it essentially goes into hibernation until conditions for growth are more suitable. Think of a bear going into hibernation as a way to explore seed dormancy. The acorn cozies up in the soil similar to the way a bear crawls into her den in the snowy winter and goes to sleep until spring comes along. As the snow melts, the bear stretches out her sore limbs and makes her way out into the bright world. The acorn feels just as good when that warmer weather comes about, and it too stretches. But rather than limbs, it stretches its fragile root out into the soil and begins the process of germination. This process allows the seed to develop into a tiny seedling — and perhaps eventually grow into a beautiful, magnificent oak tree.

Our scientists are studying seed germination in a changing climate. Learn how you can help efforts to help match plants to a changing ecosystem with the National Seed Strategy


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Speaking Science: Bringing Plant-Based Research to All Ages

Do you ever feel like trying to understand plant science research can be as daunting as deciphering a passage written in a foreign language?

As a budding plant scientist in the joint Chicago Botanic Garden/Northwestern University Ph.D. program, I find it exciting to pick through dense scientific text. Uncovering the meaning of a new acronym and learning new vocabulary can be thrilling, especially when decoding something new.

PHOTO: Kelly Ksiazek speaking in Sydney, Australia.
This past fall I spoke to a group of green infrastructure professionals in Sydney about the importance of urban biodiversity.

But the commonly used styles in scientific writing and presentation packed with language used to convey big topics in small spaces can be really off-putting to an audience of non-scientists. Many of us can conjure up a memory of a professor or teacher who seemed to like their subject matter but couldn’t convey the material in an interesting way. All of a sudden, science became boring.

Rather than struggling to learn this “foreign language,” many folks stop paying attention. Lack of scientific literacy, especially as it applies to plants, is a pity. Plants are all around us! They are so valuable to the entire planet. The very applicable field of botany shouldn’t be something that’s only discussed and understood in laboratories or scientific conferences—it should be for everyone.

This idea inspires me to try and bring my current botany research to a wide variety of people.

PHOTO: Ksiazek takes her presentation on the road to Pittsburgh.
I’ve had the chance to speak with many visitors to the Chicago Botanic Garden about my research, and typically bring some of my research supplies, as seen here from a trip to Pittsburgh.
PHOTO: Growing UP in the City: A Book About Green Roofs.
Writing and publishing a children’s book helps bring my research findings to kids all over the world.

For example, I recently realized that there are very few resources available to teach young students about the habitat where I currently collect most of my data: green roofs. While some of the methods I use for data collection and analysis can be quite complex, the motivations behind my work and some of the findings can be broken down into some basic ideas, applicable to students of all ages. So a fellow botanist and I wrote and produced Growing Up in the City: A Book About Green Roofs.

Our children’s activity book teaches youngsters about some of our research findings. The book follows a pair of native bumblebees through a city, where they guide the reader through engaging activities about the structure, environmental benefits, and motivations for building green roofs. At the end, readers even have the opportunity to ask their own research question and carry out a green roof research project of their own.

Interested in your own copy of our book? More information and a free digital download of the book are available at greeningupthecity.com.

PHOTO: Ksiazek presents her work to a girls' middle school.
Talking to 100-plus middle school girls about why it’s cool to be a botanist was a great experience!

The activity book is just one example of ways that plant scientists can engage with a broader audience and make their research findings more accessible. Some of the other activities that my colleagues here at the Chicago Botanic Garden and I have participated in include mentoring undergraduate and high school students, speaking to community organizations, creating lessons for schools and school groups, volunteering for summer programs, and maintaining a presence on the Internet through online mentoring, blogging, websites, and Twitter.

PHOTO: Ksiazek and an undergraduate student identify green roof plants.
Teaching undergraduate students how to identify plants on green roofs is one way of passing on my research knowledge.
PHOTO: Ksiazek discusses her research with a visitor to the PCSC.
My experiments on the green roof at the Plant Science Center are visible to everyone. Come take a look!

Here at the Garden, we scientists also have a unique variety of opportunities to share our science with the thousands of visitors who come to the beautiful Daniel F. and Ada L. Rice Plant Conservation Science Center. If you’ve never been to the Plant Science Center, you should definitely stop by the next time you’re at the Garden. You can see inside the laboratories where the other scientists and I collect some of our data. There are also a lot of interactive displays that aim to demystify plant science research and decode some of the “foreign language” that science speak can be. For a really interactive experience, come visit us on World Environment Day, Saturday, June 6, and talk to scientists directly. Bring your kids, bring your neighbors, and ask a botanist all those burning plant questions you have! We promise to only speak as much “science” as you want.

For more information about my research and science communication efforts, please visit my research blog, Kelly Ksiazek’s Botany in Action, and follow me on Twitter @GreenCityGal.


©2015 Chicago Botanic Garden and my.chicagobotanic.org