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SCIOGRAPHIES Q&A: EVOLUTIONARY BIOLOGIST ALASTAIR SIMPSON

Posted by staff on September 26, 2019 in All News
(Photo by Nick Pearce)
(Photo by Nick Pearce)

Sciographies is a radio show and podcast about the people who make science happen, brought to you by the Faculty of Science and campus-community radio station CKDU. This article is the third in an eight-week series that features excerpts from each new Sciographies episode this fall. You can find Sciographies on Apple and Android podcast apps, by tuning in to CKDU 88.1 FM in Halifax at 4 PM Thursdays (until October 31), or by visiting dal.ca/sciographies or soundcloud.com/sciographies.

Listen to preview of episode.

Few people can say that they’ve described a new species, but Alastair Simpson is one of them. The allure of discovering the unknown first drew Dr. Simpson to the field of evolutionary biology during his undergraduate studies in Sydney, Australia. Years later, he has indeed contributed a wealth of knowledge to the scientific literature around microbial evolution.  

Now a professor in the Department of Biology, Dr. Simpson supervises a team of passionate students who mirror his own fascination with some of the smallest and poorly-understood lifeforms on Earth: eukaryotic microbes. Also known as “protists,” these microbes have complex cells—just like we do—but they don’t belong to the animal kingdom, and they aren’t plants or fungi either. Eukaryotic microbes form many different branches on the Tree of Life, and Dr. Simpson is particularly interested in species that are predators; the ones that eat other microbes to survive and reproduce themselves.

In this week’s episode of Sciographies, host and oceanography professor David Barclay speaks to Dr. Simpson about a widely-publicized paper his team published in Nature last fall, and how studying the genetic information of microbes helps us better understand the evolution of complex lifeforms on Earth. They also take a break from the science to discuss the sport that helps Dr. Simpson get through Canadian winters. Here are a few excerpts.

Dr. Simpson (right) on the hunt for microbes living in this hypersaline pond in Curacao.

Dr. Simpson on discovering, naming and observing a new species…

Simpson: The species’ is name is Hemimastix kukwesjijk, and we chose that name because it’s derived from the name of an ogre from Mi’kmaq folklore [“Kukwes”].

Barclay: It makes sense because these things are eating other eukaryotes. So that’s a little scary.

Simpson: Also, they have very large numbers of what are called flagella—so, hairs—on them.  They happen to be quite hairy organisms. So, yes, a ravenous hairy ogre seemed like a good fit.

Barclay: And they use these hairs to actually entrap their prey?

Simpson: Yes. They use their flagella for two reasons. One is to swim around... They hunt down their prey, in fact. Then [the flagella] are used to grab prey in a sort of basket at the front of the cell. It’s part of the mechanism for trapping their prey. And then [the microbe] fires harpoons into it, to kill it off. Finally, it absorbs the prey… kind of sucking it up at the front of the cell.

Barclay: Pretty gruesome stuff. So, have you directly observed that under a microscope?

Simpson: We have... It’s dramatic. We’re used to looking at microbes, but to us it’s like looking at a nature documentary where the cheetah gets the gazelle. They capture these cells and consume them within a couple of minutes. It’s an exciting thing to see.

On finding new hobbies in Canada…

Barclay: Since you’ve been in Halifax a little while now, have you taken up any of the winter activities that are so afforded here?

Simpson: For the last eight or nine years, I’ve become a pretty addicted curler… it’s a really useful way of getting through a Halifax winter, I must say. It’s a fantastic sport, and it’s great fun to introduce new people to it. We’ve taken groups of graduate students from all over the world out [to play]. We’ve rented the ice to give them a unique Canadian experience, and they typically love it

Barclay: Is there an analogy here? Do you imagine the stones as microbes?

Simpson: Well, I might now!

 

*Excerpts were edited for length and format.