Evolution

“People can achieve great success in things, but that doesn’t mean everything comes easily to them.” - Dr. Cassandra Extavour

Cassandra Extavour grew up in a mixed race household in the Caribbean community of Toronto. She did not know that she liked science until high school. Before that, she was thinking of becoming a baker or musician. Her interest in genetics grew during a summer internship at the University of Toronto. Currently she is Professor of Organismic and Evolutionary Biology and of Molecular and Cellular Biology at Harvard University. Her lab works on the evolution and development of germ cells in animals, the genetic control of reproductive capacity, and the evolution of the arthropod body plan.

In her PhD thesis, Extavour demonstrated that germ cells engage in cell to cell competition before becoming a gamete. This means that natural selection is happening on the cells that will become the gametes that give rise to the next generation. Her lab's research focuses on the understanding of early embryonic development, the genes that are responsible for development and the evolution of these genes. They use several different model organisms, most of which are insects like fruit flies, to study the evolution of reproduction and development.

While researching Cassandra Extavour, I learned that she is like the majority of college students. Some college students do not know exactly what to do but I bet we will find it sooner or later. 

Curated by Introduction to Biology student Jorge Enriquez Gomez

Dr. Rachael Bay is an Assistant Professor at UC Davis, where she began her tenure in 2018. After receiving her undergraduate degree in Marine Science/Biology from the University of Miami, she went on to pursue her Master’s Degree in Biology from Dalhousie University. She then received her Ph. D. in Biology from Stanford University, and was a National Science Foundation postdoctoral fellow at UCLA before joining the team at UC Davis.

The Bay Lab at UC Davis studies how human-induced environmental changes alter evolution. A combination of ecological and physiological experiments are conducted to determine how humans impact evolution in wild populations, mainly in the ocean. Dr. Bay and her colleagues study how animals respond to changes in the environment caused by humans, and also how evolution might mitigate some of the negative impacts caused by humans.

While reading through Dr. Bay’s published research, I was surprised to learn of the extent of coral bleaching-induced mortality. Research conducted in part by Dr. Bay shows that reef-building coral species are declining drastically due to increased marine heatwaves, which is in turn causing bleaching-induced mortality. I was unaware that an increase in the temperature of the ocean could have such a drastic adverse effect on various species of coral. It is alarming to see that such a seemingly small change in the ocean temperature can have such a large impact on the environment and living creatures.

In 2019, Dr. Bay was one of four recipients of the Sloan Research Fellowship, worth $70,000. Her plan for the fellowship was to survey thermal tolerance in the Pacific Ocean. Regarding her studies, she was quoted as saying “There’s some sort of balance between getting just enough exposure to high temperatures to learn how to deal with them and being repeatedly stressed enough to actually threaten your survival.” She is excited to use the fellowship to continue exploring some ideas she has been thinking about to continue her research.

Curated by Introduction to Biology student Dave Ortega

Patricia (Patty) Brennan is a biologist who studies genital evolution in many animals. She received her undergraduate degree in Marine Biology in her native country Colombia. Then joined a research team and examined the marine mammal populations around the Galápagos Islands in Ecuador. After her time around the islands, she came to the U.S. to obtain her P.h.D. at Cornell University in the Neurobiology and Behavior program. After her studies, she is now a professor of biology at Mount Holyoke College.

Brennan has a strong interest in sexual selection and mating system evolution, and that is when she decided to study this topic further for her post-doctoral project. So far she has studied bird genitalia, snakes, bats, and sharks. One of her more well-known projects was focused on male duck genitalia. In her article she speaks about how the genitalia of the male and female ducks have evolved and now how they are specially designed for reproduction. She also talks about how females can find tiny differences between males and uses that to their advantage to obtain sperm from preferred males. 

When I came across Patty Brennan’s research, I was introduced to the study of genitals. I thought this topic was quite strange, but after reading many of her publications I was surprised at how much genitalia can impact evolution. I was a little concerned about the controversy she stated, saying how she was ambushed by opposers who thought that studying genitals was a waste of money. I then realized that although she has been given a rough time studying this field of work, it is her passion because she has a full lab team with many undergraduates and Rachel Keeffe who is also a fellow Doctor. 

Curated by Introduction to Biology student Alyssa Nott

Hopi Hoekstra was born in New York City, she is an evolutionary biologist and curator of mammals at the museum of comparative zoology at Harvard University. She first received her bachelor's degree in Biology for UC Berkeley. She then went to the University of Washington and there she received her PhD.  After spending some time at the University of Arizona and UC Berkeley completing postdoctoral fellowships, she landed at Harvard where she joined their staff. She is very well known and respected for her numerous papers in scientific journals and has received many awards for her work and contributions to science and education.  

As for today Hoekstra is putting her focus on studying the genetic basis of adaptation in mice, specifically she wants to identify the genes and genetic changes that have allowed mice to not only survive but thrive in different environments. Back in 2013 Hoekstra and her team made a big breakthrough and identified the genetic changes that eventually led to the evolution of the darkening of coat color in mice that live in beach and dune environments. She has also conducted research on behavior and sociality in mice, and studied the effects of climate change on those mice. Through all her work and research she was able to publish a recent study about how mice are adapting to warm and dry conditions by evolutionary changes in their physiology and behavior. So all of Hoekstra’s work is very important to understand evolution, genetics, and their relationship between organisms and different environments. 

While I was researching Hoekstra I was able to learn quite a bit of interesting things, mainly focused on genetic changes and adaptations. The most interesting topic to read about was the rat’s coat color changing to a darker color in order to survive in beaches and dune environments. They  do this for a number of reasons, the main reason is to be able to hide from predators, but also to adapt to the warmer climate. She also went into great depth in her research about sociality and mating behaviors among mice and how they have changed over time. 

Curated by Introduction to Biology Student Jonah Graziano

“Spiders are my inspiration. I'm always learning something new from them, which is what keeps my research going” — Cheryl Hayashi

Cheryl Hayashi is an accomplished scientist, known for her research on spider silk and genetics. She earned her Bachelor's degree in Biology from Yale University, and went on to earn her Ph.D. in Biology from UC Davis. After completing her doctoral studies, she worked as a postdoctoral researcher at the University of Notre Dame, where she studied the molecular biology of silk proteins. She then joined the faculty at the University of California, Riverside, where she is currently a Professor of Biology and Director of the Keck Center for Behavioral Biology. 

Cheryl Hayashi is a prominent biologist who has dedicated her career to studying spider silk and its genetic makeup. Her research has focused on understanding the molecular structure of spider silk proteins, as well as the evolutionary history of spiders and their silk production. She has explored the ways in which spiders use their silk to capture prey, build webs, and protect their eggs. Through her work, Cheryl has made significant contributions to the fields of materials science and biotechnology, with potential applications in areas such as medicine and construction. Her research has also shed light on the fascinating world of spiders and their remarkable abilities to produce one of the strongest and most versatile materials found in nature. 

I've learned about the remarkable characteristics of spider silk and how it has the potential to impact industries such as medicine and materials science through my research on Cheryl Hayashi's work. I've also learnt about spider biology, including their evolutionary history, the variety of silk production, and the intricate behaviors they exhibit when making webs and defending their young. 

Curated by Introduction to Biology student Samantha Mejia