Skip to main content
Loading Explore guides…
Art and Science Connection · Acedra
Home
Explore
Biology
Art and Science Connection
Sign in to save
Chat
If YouTube asks you to sign in, open the video on YouTube.
Watch on YouTube
Reload player
Transcript
101 segments
Copy
Hide video
0:01
(ethereal music)
0:38
- My name is Usha Farey Lingappa, and I am a scientist.
0:42
Specifically, I'm a geobiologist, which means that my work involves studying the relationship and the interactions between life and the geological world.
0:54
In addition to being a scientist, I'm also an artist.
1:00
And I wanted to talk about that here because, often, art and science are seen as two very different paths you might take. But to me, they really go hand in hand.
1:16
Like science, art can also involve observing and trying to understand the world around us, and then expressing and communicating that understanding. In my career thus far, I've actually found that doing each can really strengthen the other. Like looking at the world as both an artist and a scientist can give you a pretty unique perspective that can be really valuable for both the art and the science. When I do scientific field work, which, as an earth scientist, I do quite a lot of,
1:49
no matter how much science gear I have to carry, I always bring a set of paints too.
1:55
I really enjoy creating landscape paintings of my study sites, because in a painting, you can highlight and showcase details that would otherwise be lost in a photograph. Like in the example that I'm showing here, the rocks in that upper part of the cliff were textured with ripples, which told us that that was once an ancient river bed. And that was part of why we were studying those rocks in the first place. But that detail is impossible to capture in a photograph like this.
2:29
In a painting, though, you can bring it out.
2:33
Bringing this type of artist perspective to science can also actually really help the science in ways that go way beyond just being able to create nice pictures of things.
2:44
When you sit down and try to draw or paint a picture of something, you are going to notice so many details that you never would have otherwise if you had just taken a photograph instead. And sometimes those can be really important details that you wouldn't have known to look for. And that is something that is true really broadly. When you look at the world in different ways, from different perspectives or different mindsets, you're going to notice different things.
3:18
And that can really fuel discovery. So let me tell you a little bit about how I got to this point.
3:26
Growing up, really my whole life, I have always felt a pretty strong sense of just wonder and appreciation for the natural environment. So I guess it's not the out surprising that I ended up doing what I do now. But my path to this point wasn't super direct.
3:47
For a lot of my childhood, I was a big theater kid. That was really my biggest interest and focus for a long time. Then when I was a teenager, I also started painting a lot.
3:59
When I went to college, I went with the intention of studying visual arts,
4:05
but pretty early on in my college education, I totally redirected my studies to focus on science instead. I became fascinated with astrobiology, which is the search for life in the universe. Things like thinking about the possibilities of life on other planets beyond the earth. And as part of that, trying to understand the scope and the limits of life on earth and how life elsewhere might be totally different from anything we know of here.
4:34
It didn't occur to me that my interest in art and my interest in science might have something to offer each other
4:42
until I did my undergraduate thesis project.
4:46
I did that project on the chemical origins of life. So exploring ideas of what chemistry could have been involved for life to first begin.
4:58
And I illustrated it. The art side of that project started out as more like visual clarifications for the science ideas, really more like diagrams than really art. But the deeper I went into that project, the more the art component grew and evolved and eventually actually started shaping how I was approaching thinking about the science side.
5:26
That was how I learned that approaching science from the perspective and mindset of an artist can actually lead you in some really interesting directions.
5:39
After I finished college, I didn't know exactly what I wanted to do. So I spent a few years working before deciding to come to Caltech for my PhD.
5:49
For the research that I did here, I moved forward in time from that origins of life project to study the origins of photosynthesis. And that's the work that I'm going to share with you today.
6:01
First, I'd like to get us all on the same page about time.
6:06
The planet earth is about 4 1/2 billion years old.
6:11
That is a really long time.
6:15
And life originated pretty early on in that time. We don't know exactly when, but we're pretty sure that the earth has hosted life for most of its existence.
6:25
Now humans have been around for maybe 300,000 years. Obviously for us, that's a really long time, but compared to the length of the whole history of the earth, that's nothing. That's too small to even show up on this time scale of the history of the earth. So to put us up here in sort of much more general terms, here's vertebrates.
6:49
Vertebrates are any animals with backbones. So obviously that includes us, but also many other very different creatures as well.
6:59
Vertebrates have been around for a little bit more than 500 million years, starting with some little worm-like creatures and eventually ending up with us and many of the other animals that we know and love today. And, of course, for a little bit in between, included dinosaurs.
7:16
The point that I'm trying to make here is that the history of life on earth spans a huge amount of time. And for a really big chunk of that time, there weren't humans, there weren't dinosaurs, there weren't any animals or even plants. For a very long time, life on earth was all microbes, like, for example, bacteria. Now, oxygenic photosynthesis has existed for about half of the history of the earth.
7:47
Oxygenic photosynthesis is the process of harnessing energy from sunlight to take water and carbon dioxide and make oxygen and sugar. You've probably learned about this in school, right? This is the thing that plants do at the bottom of the food chain. In fact, it's not just plants that do it. It's also algae and a group of bacteria called the cyanobacteria.
8:12
This process is so important to life as we know it.
8:17
I just wanna stress that because it's so easy to not think about and just take it for granted, but literally all the oxygen we breathe, all the food we eat, really the fact that we can even live on this planet at all is fundamentally thanks to oxygenic photosynthesis. So when it originated halfway through the history of the earth, it changed everything. Before there was oxygenic photosynthesis, there was no oxygen in the air. By releasing the first oxygen,
8:52
oxygenic photosynthesis completely changed the chemistry of the atmosphere, the oceans, basically every environment on the face of the earth. It also completely changed the possibilities available to life.
9:07
This transition is really what opened the door for the evolution of big complex lifeforms that breathe oxygen, right, like us. Now, in addition to trying to understand how this process evolved, another really big question is understanding how life managed to survive evolving it.
9:28
And that is because, by introducing oxygen,
9:33
it also introduced oxidative stress.
9:38
You may have heard of oxidative stress because it can be the root to a lot of medical problems for us. Oxidative stress is really just a huge issue for biological systems, and it's caused by chemicals that come from oxygen. So in a world with free oxygen in the air, oxidative stress is just an inherent threat.
10:00
Now, since we have evolved to rely on oxygen, our biology has developed some pretty sophisticated mechanisms that keep that stress in check most of the time.
10:11
But back when the very first oxygen was introduced to the environment, those protections didn't exist yet. Because of that, the origin of oxygenic photosynthesis probably also caused a devastating mass extinction event and killed off much of the life that existed at that time.
10:31
So a lot of the research that I did in my PhD was about trying to better understand this pivotal moment in the history of life on earth, both how did this ability evolve and also how did life survive evolving it.
10:47
Now, if we want to study events that happened in the distant history of life,
10:53
there's sort of two different approaches we can take which give different perspectives on that same history. One approach comes from biology, and the other from geology. And I use both. And sort of like what I was saying before about how looking at the world as both an artist and a scientist
11:17
gives me a unique perspective, I think that approaching this science question as both a biologist and a geologist gave me a pretty special perspective on it that I would not have been able to get if I had only taken one of those approaches alone. So I'm going to share with you a little bit about both of those types of work.
11:38
On the biology side, we can study the life that exists today. Because today's life can retain some similarities to its ancient ancestors, and studying it can tell us a lot about how biological processes work and how they may have evolved.
11:55
Now, because what we're talking about right now is the origin of photosynthesis. Of these three groups here, the key one is the cyanobacteria. Plants and algae didn't show up until quite a bit later. The earliest plants were a little less than 500 million years ago. And the earliest algae were about 1 billion years ago. And in any case, plants and algae both got their ability to do photosynthesis already fully formed from the cyanobacteria in the first place.
12:24
Plants and algae use organelles called chloroplasts to do their photosynthesis, and chloroplasts are basically just kidnapped cyanobacteria inside their cells. So the origin of this ability is something that evolved in the ancestors of the cyanobacteria.
12:42
Because of that, a lot of my work involves studying them.
12:46
Now you can see from my picture here that cyanobacteria come in a very broad range of different shapes and sizes.
12:55
To show you just how true that is, here's a bunch of pictures that I took through a microscope of cyanobacteria that I found in the wild.
13:05
They're really fantastic and awesome bugs to get to work with. There are literally thousands of different species of cyanobacteria, and you can find them in basically any environment that sees sunlight, even if it's just the tiniest bit of sunlight.
13:21
Now studying microbes in the wild like this can be very valuable for learning things about their diversity. So how many different types there are, how many different places they live. And also their ecology, so like how do they interact with their environment and the other life around them in that environment.
13:42
But natural settings can often be
13:46
way too complicated of situations to really carefully examine specific biological processes in. So that's why we also studied them in the lab where we can isolate one species and grow them under carefully controlled conditions to do experiments that allow us to study specific aspects of what they do and how they work.
14:10
The main cyanobacteria that I worked with in this way is this one called Synechocystis, that you can see here. I grow it in either these flasks or tubes like this.
14:22
Yeah, so the biology side of my work, to understand the origins of photosynthesis, involved studying cyanobacteria, both in the environment and in the lab to better understand them and how they work and, by extension, how their ancestors might have worked. Now on the geology side, we can learn about the history of life by studying ancient sedimentary rocks, because those rocks can preserve a lot of information about the environments from the time they formed.
14:53
and also the life that existed in those environments. Think fossils, for example.
14:59
So by studying those rocks, we can decipher a lot of that information.
15:05
Now, unlike plants and animals, which are big and complicated enough to leave behind a good record of body fossils, fossils of individual bacteria, they can exist, but they can be really hard to identify really definitively. So instead of individual cells, one of our best records of life during this time comes from something called stromatolites.
15:32
Stromatolites are these features in sedimentary rocks where you have layers growing up from a surface that form domes or columns like this. Here's a picture of a real example in a rock from South Africa. You can see these curved layers building up into these columns in this rock.
15:55
What these are often interpreted as are the lithified remains of something like a microbial mat.
16:02
What's a microbial mat? Well, here's a picture of a live one. It is built out of layer upon layer of bacterial growth. This one comes from a tiny uninhabited island in the Caribbean, where I did a lot of field work, because this island has this spectacular tidal lagoon that is just full of these mats. Today, we have to go to pretty remote and special environments like this one in order to find such thick and pristine microbial mats as this. But before the rise of plants and animals,
16:39
this type of environment, or ecosystem, is really what dominated a lot of the earth's shallow water environments. Now, in addition to physical fingerprints of life, like fossils and stromatolites, another thing we can look for in ancient rocks are chemical fingerprints of life, like how the products of life can be reflected in the chemistry of the rocks. So a good example of this is
17:08
the origin of oxygenic photosynthesis is marked by a very clear transition in the composition of rocks based on how introducing oxygen in the environment changed the chemistry of the environment.
17:21
So the geology side of the work that I do is to study these rocks from right around the time of that transition, looking for both physical and chemical clues that will help us understand what was going on.
17:36
My specific work involved looking at the element manganese.
17:41
Manganese is a metal. It's element number 25 in the periodic table. And we think that it played a key role in the evolution of photosynthesis. Because of that, I spent a lot of time looking at the manganese in these rocks. One of the coolest things we found was this unit of stromatolites. that was literally entirely cocooned in manganese.
18:07
This picture is an x-ray map showing the distribution of manganese in one of these rocks. You can see the stromatolite columns here are defined by the manganese. That's really cool. What it tells us is that these ancient photosynthetic microbes, from right at the time of that transition, the evolution of photosynthesis, they were all about manganese.
18:34
Now, meanwhile, on the biology side, I also did a lot of work studying how cyanobacteria use manganese. And we discovered that in addition to the role of manganese in the evolution of photosynthesis itself, cyanobacteria use manganese as an antioxidant system that helps them fight oxidative stress and in a way that is much simpler than many of the other biological defenses against oxidative stress that we know of today. What this means is that manganese could be the key
19:07
to both sides of the origins of photosynthesis question, not just how did the ancestors of cyanobacteria evolve this ability, but also how did they survive evolving it. Like the fact that they were all about manganese meant that they had a builtin antioxidant system. That explains how they could possibly survived the sudden new levels of oxidative stress that came with releasing the very first oxygen.
19:38
Without that, they probably wouldn't have survived that transition. Oxygenic photosynthesis might never have taken off. And the history of life on earth could have gone totally differently.
19:52
This realization adds a really cool piece to our understanding of this critical turning point in our history.
20:00
And we never would've been able to figure it out if we hadn't approached this question from both biology and geology, right? These two separate scientific disciplines that have traditionally been done pretty separately. We came at this question from both these sides, and then we used what we learned from one
20:22
to strengthen our understanding of what we learned from the other.
20:26
On a deeper level, I also think that my artist mindset played an important role here here.
20:33
Not visually like in the landscape painting example that I gave earlier, but just in how I thought about the question.
20:42
It was through my unique mindset and perspective that I approached trying to understand all these different details and how they fit in the big picture, to make these connections, to pull out this story. If someone else with a different perspective than me had embarked on this project instead of me, their thought process might have taken them in a totally different direction, and they might have figured out some totally different part of the story than I did.
21:12
Something likely just as interesting and important, but just different
21:18
Now to continue with this theme of how different perspectives can shed different light on a question, I wanna give you one more example, which is how studying the past can sometimes illuminate unexpected things about the present too. Because making these connections between cyanobacteria bacteria and manganese in the context of the ancient earth actually unexpectedly led us to solve a mystery about the modern earth as well. This is rock varnish. Rock varnish is this very hard, thin, dark coating
21:57
that forms on exposed surfaces of rocks in the desert. This picture that I'm holding, or this rock sample that I'm holding in these pictures on the right here is a pretty good example, where you can see the top surface of this rock is totally covered in this dark varnish material, while the underside of the rock looks totally different.
22:18
What's weird about this stuff is that it contains crazy high levels of manganese,
22:24
way more manganese than you'll find in the underlying rocks or in nearby desert soils or dust
22:33
or any other surrounding materials.
22:37
Unfortunately, this stuff forms way too slowly to be able to study it and really watch how it forms in real time. Because of that, trying to understand how it forms, and in particular, how you end up concentrating all this manganese on these rock surfaces, has been a pretty longstanding scientific puzzle.
22:59
People have been debating for decades whether or not biology could be playing a role here, because we know there are microbes that live in varnish, but figuring out whether they actually are responsible for forming it or whether they just happen to live there is a pretty hard question to answer. And up until now, no one had come up with any really compelling explanation for how or why the biology that's associated with varnish could be responsible for this manganese situation.
23:35
But here's the thing.
23:38
The most common species found in varnish is a cyanobacteria called Chroococcidiopsis.
23:45
Remember that thing I told you about how cyanobacteria use manganese as an antioxidant system to fight oxidative stress? To do that, they suck up as much manganese as they can from their environment, and they concentrate it in their cells. And it turns out Chroococcidiopsis does this way more intensely than our old friend Synechocystis And that makes sense when you consider what sets them apart.
24:15
Synechocystis is a freshwater bug that grows in pretty moderate conditions, but Chroococcidiopsis is a desert bug. That means needs to be able to tolerate things like heat and radiation from the sun and desiccation, all of which are things that make oxidative stress way worse. So this manganese system is going to be that much more important. And that's the thing about where you find varnish. Exposed surfaces of rocks in the desert are an environment that is constantly bombarded by the sun,
24:52
subject to a ton of oxidative stress. If that's your habitat,
24:58
hoarding as much manganese as you possibly can in your cells to fight that oxidative stress is going to be an extremely valuable adaptation and is probably what enables these cyanobacteria to live there at all.
25:13
Realizing that provides a pretty good explanation for the mystery of how you concentrate so much manganese in rock varnish, right? This is what's left by generation after generation of these cyanobacteria using manganese to be able to thrive in this environment, in spite of all the oxidative stress that they're encountering. By using this adaptation that ties all the way back to how their ancestors survived the origin of photosynthesis. The thing that both the artist
25:45
and the scientist in me loves the most is that this story about manganese and cyanobacteria
25:53
is just one of so many different intricate and complicated and fascinating and beautiful things about how our world works that is going to be discovered by people looking at old questions in new ways. The fact that I was able to contribute what I did to these projects was precisely because of the unique perspective that I brought to the table, right? Thinking about these questions as an artist, as a biologist, and a geologist, as all of the other things that make me me, right?
26:29
That meant that I thought about these questions in a way that was just a little bit different from every scientist who thought about them before me. So all of this is just to say, if you are interested in science, but you feel like you don't exactly fit the mold, the conventional mold of what it can mean to be a scientist,
26:53
keep in mind that new perspectives and different perspectives really are the key to making progress.
27:03
With that, I would like to thank you all so much for watching.
27:09
- Thank you for attending today's Science Journey presentation. Here at Caltech, we thank Mitch Aiken and Kitty Cahalan of the Center for Teaching, Learning, & Outreach, as well as Mary Herrera and Cara Stemen from the Office of Public Programming, and the teams from Academic Media Technologies and Event Productions. And special thanks to Robin Javier and Brian Brophy. Additionally, we thank the Caltech Employees Federal Credit Union, the Friends of Beckman Auditorium,
27:37
and our many sponsors who make these programs possible.
27:41
We look forward to you joining us again for future science lectures and performing arts events. Learn more by visiting events.caltech.edu. (upbeat music)
Here to help you learn
Sign in to keep a private conversation with your course tutor.
Ask me anything about the material…
Sign in to chat