Shedding light on unknown origins.
Have you ever found a leaf on the ground and noticed the delicate network of veins? If you hold it up to the sun, you can see the veins break into smaller and smaller branches, delivering water to each of the leaf’s cells. Have you ever wondered what’s really going on in there? How did the seed know which direction was “up” so that it could reach toward the sun? How did the plant even know to grow the leaf at all? These kinds of questions captivated a scientist named Marie Clark Taylor.
"Unfortunately there isn’t a lot we know about Dr. Marie Clark Taylor’s life... much of her story and the extent of her contributions have been lost to time. This is all the more reason to appreciate Dr. Taylor’s work and to celebrate her dedication to Botany, preservation of the natural world, AND education!"
Watch the video or continue reading below!
Marie's Early Career and Education
Marie was born in Sharpsburg, Pennsylvania in 1911, and knew from a young age she wanted to pursue the highest levels of education. She studied botany at Howard University, and earned her bachelor’s degree in 1933, then her master’s degree in 1935. Marie Clark Taylor taught high school biology and served in the Army Red Cross for six years before starting her doctorate at Fordham University, in the Bronx, New York City.
In 1943 she earned her PhD in Biology, becoming the first woman to ever earn a PhD in science from Fordham. She was also the first Black woman to ever hold a PhD in the entire field of Botany!
Dr. Taylor’s PhD research involved experiments with plants that were just about to grow flowers. She was interested in learning how a plant’s growth and flower development is affected by exposure to light for varying lengths of time. For example, a question Dr. Taylor might have asked is “Does the flower bloom faster if it receives 8 hours of light, rather than just 4 hours?”
These kinds of research questions, about how plants respond to light, are related to the phenomenon called photomorphogenesis. Sheesh, that word sure is a mouthful. Let’s break it down so we can understand what the parts mean!
The first part of the word is
This prefix means “related to light”— just like how a “photograph” is a visual image created by capturing light.
The next part is
This makes me think of something morphing, or changing shape. And indeed, “morpho” means “form” or “shape”.
The final bit is
The word genesis refers to an origin, or the beginning.
If we put all these pieces together, we find that
photo - morpho - genesis
means light causing form or shape to emerge.
Let’s think about what photomorphogenesis could mean for a little seedling.
"Dr. Taylor helped us understand how plants decide on the perfect moment to bloom."
Plants have sensors called "photoreceptors", which can sense whether or not light is hitting the plant.
If there is not very much light available to the seedling, like when it is still underground, the photoreceptors do not detect any visible light, so they tell the plant to keep growing until it can emerge from the soil. It will be very long, thin, and pale. This allows it to grow far distances without using too much energy, while it searches for a light source. Without light, a new seedling will not grow leaves, since it doesn’t need those beneath the soil.
However, once the photoreceptors detect visible light, they switch to telling the plant to grow leaves and roots. Now the seedling’s stem grows slowly, meaning the majority of its energy is available to put down roots, and produce leaves with chlorophyll so that it can begin to convert sunlight into energy.
The seedling’s ability to tell the difference between dark and light, and then change its growth pattern accordingly, is an example of photomorphogenesis, and is precisely what Dr. Taylor wanted to learn about.
Another example comes from flowers. You may have noticed that some flowers only bloom in certain seasons. For example, tulips bloom in the spring. One reason for this is that plants can use photoreceptors to measure the length of the day! Because the day gets shorter in the winter and longer in the summer, plants can use photoreceptors to figure out what season it is, and Dr. Taylor helped us understand how plants decide on the perfect moment to bloom.
A Dedicated Educator
After completing her PhD, Dr. Taylor went back to teaching high school for a few years. She then returned to Howard University in 1945 as an Assistant Professor of Botany and went on to serve as the Head of the Botany department from 1947-1976. During nearly 30 years as the head of Howard Botany, the department expanded greatly under her leadership. Dr. Taylor mentored many Botany students, helped design the biology building, and oversaw construction of a greenhouse!
Dr. Taylor spent a lot of time as a University professor, teaching classes, conducting research, and running a Botany department. But she never forgot her passion for teaching high school! She spent many years of her early career teaching in high school classrooms, and after becoming a professor she continued to spend a lot of time improving science teaching in public schools. She worked with the National Science Foundation to offer training for high school teachers every summer, and helped high school teachers continue their own educations so that they could teach their students even better.
She encouraged high schools to use real biological materials, rather than just drawings, as well as light microscopes! Dr. Taylor once said “The encouragement of students to investigate the various living specimens …is rewarding in many aspects. It can initiate civic awareness of the minutiae in natural balance and wise use of natural resources”.
So if you’ve ever used real plants in a science class, you probably have Dr. Marie Clark Taylor to thank. Dr. Taylor’s dedication to improving high school education was so important and renowned that President Johnson heard about her work with teachers, and asked her to implement science curriculum changes across the nation, and even internationally.
Unfortunately there isn’t a lot we know about Dr. Marie Clark Taylor’s life. She died in 1990, and like so many women of color throughout history, much of her story and the extent of her contributions have been lost to time. This is all the more reason to appreciate Dr. Taylor’s work and to celebrate her dedication to Botany, preservation of the natural world, AND education! By learning about Dr. Taylor and about her research, her legacy is preserved and she continues to inspire others. So next time you take a trip outdoors, remember to stop to smell the flowers and appreciate the light that helps them grow.
Photos courtesy of Howard University and Fordham University
Written by Madelyn Leembruggen, Nicole Naporano
Edited by Ella King, Abhijit Mudigonda, Justina Yang
Original illustrations by Nicole Naporano
Portrait by Jovana Andrejevic
Primary sources and further reading:
Spring 2008 issue of Quest by Howard University
“International Day of Women and Girls in Science” from Fordham University Library
"From High School Biology Teacher to Trailblazing Scientist: Remembering Fordham Alumna Marie Clark Taylor" from Fordham University Magazine
Learn more about botany and how plants respond to light!
Observe (45-60 minutes): Did you know that plants have favorite colors of light? Try making a leaf filter to discover a plant's favorite color.
Investigate (2-3 weeks): Grow your own bean sprouts and see if you can answer the question: How does light affect plant growth?