Andrew Hendry: The Changing Views and Speeds of Evolution
The word evolution generally conjures images of millenia-long timescales. Maybe the 15 million years it took for whales to evolve, or the 2.5 million years it took to get from Australopithecus to modern humans. But over the last few decades, scientists have begun to realise that some forms of evolution can take place over much shorter timescales. Leading this field has been Professor Andrew Hendry, author of Eco-Evolutionary Dynamics, a “masterful, comprehensive synthesis treating most of today’s hot topics in ecology and evolution”.
On a recent trip to Trondheim, Kate Layton-Matthews and I were lucky enough to sit down and talk to Andrew about contemporary evolution and the reaction to his book, including the advent of an interesting promotional technique.
Sam Perrin (SP): You’ve been publishing for about 25-30 years now. In that time, how have you seen the landscape and attitudes to ecology and evolution change?
Andrew Hendry (AH): Attitudes to evolution have changed fundamentally. There’s been a huge shift in the thinking about the pace at which evolution takes place. When I started, almost everybody though that evolution was always really slow, and now almost everybody thinks it can be quite fast, in almost every ecosystem. So that’s a huge change, which then also permeates back into ecology, into eco-evolutionary dynamics, with the idea that if evolution is really rapid, and traits are evolving and interacting with the environment, that should feed back to influence the ecological environment, communities, ecosystems.
Of course the other massive change has been sequencing technologies. Now you can have a full genome for 100 dolars. Back when I started you could only get allozymes, which were very exciting at the time, but now exceedingly primitive technology with limited inferences. So those are two massive shifts in just the structure of ecology and evolution.
Kate Layton-Matthews (KLM): In late 2016, you published Eco-Evolutionary Dynamics. For those who haven’t been exposed to this field before, how would you sum up the differences between eco-evolutionary dynamics and evolution?
AH: Part of eco-evolutionary dynamics is just evolution. It’s the idea that ecological change can drive rapid evolutionary change. But then the other part of that is that as those traits are evolving and having ecological effects. So the most novel aspect of eco-evo dynamics is this increasing interest in how rapid evolution is having ecological consequences, on population dynamics, on community structure, on ecosystem function, which then has spin-offs for conservation, for biodiversity, ecosystem services, for tipping points.
The simplest way of drawing any conceptual diagram is 2 boxes and two arrows. Here the boxes are ecology and evolution, arrows going each way, ecology influencing evolution and evolution influencing ecology. So eco-evo dynamics is uniting those 2 things together, instead of just the classic study of how ecology influences evolution. It was assumed that the other arrow from evolution back to ecology was just too slow. If you’re an ecologist, you could just ignore than part. The novel part of the book is where I emphasise that aspect. Where the evolution as it’s occurring right now is having immediate ecological consequences.
SP: How was reaction to the book in general?
AH: Generally good. I knew the topic hadn’t been written about that much before, so I knew it was potentially something that people would find useful, but I had no idea whether people would like it or not. At the start there was a bit of a delay period where I wasn’t hearing much, and then graduate student groups started reading it, and then I started getting quite a bit of positive feedback. It’s a new field, and I’m trying to expose other people to this field.
SP: The #PeopleWhoFellAsleepReadingMyBook movement, where did the idea for that come from?
AH: The first time I ever saw the book in my hands, I got it and sat down in my chair and was leafing through it, and was feeling kind of sleepy. And I thought it’d be funny if I took a picture of my book and me sleeping with it. So I did that and then tweeted it out, and then about 10 minutes later a friend of mine, Dan Bolnick from the Bolnick Lab at the University of Texas, sent a picture of him sleeping with it as well, and from then it had to be a thing, so I created the hashtag and promoted it that way. It’s been a really fun way to promote the book without being obnoxious about it. If you’re always saying ‘read my book’, it gets annoying, but if you have practising people in the field, taking pictures sleeping on your book and buying into that hashtag, then it’s a lot of fun. The publisher loves it too.
SP: Do you think that a lot of the reasons this has become so relevant is the onset of extreme impacts of climate change and human activity in general?
AH: I think there’s an element of that. Most of the examples of really rapid changes in traits are associated with human disturbances. So that’s a substrate for studying how evolution will have ecological effects. And so most of the studies that are not experimental, that look at eco-evo dynamics, tend to focus on climate change scenarios, hunting and harvesting, pollution, or invasive species. When you study rapid evolution of traits in the context of human disturbances, you’re not usually interested in the traits themselves, you’re interested in the dynamics of that population. How many are there, what’s the growth rate of the population, is it declining? And what is the influence of evolution on that? And then you can link the services that organism is providing, the way which it influences the community. There are all sorts of confluences of these ideas. It’s the right time to bring these things together.
KLM: That brings us to invasive species. They make rapid evolution quite an important thing to look at.
AH: Yes, I think there’s plenty of examples now whereby upon the introduction of an alien species the evolution of native organisms is having fundamental consequences for their dynamics. Not just the dynamics of their traits, but the consequences of that for the dynamics of the population as a whole. Their abundances, their changes through time, interactions with alien species.
SP: There’s been some interesting research going on with regards to cane toad introductions in Australia.
AH: Yes, a lot of smaller snakes, for instance, can’t eat cane toads, and as a result they don’t die, so you have the evolution of smaller snakes, basically. There’s a whole lot of species evolving in response to cane toad invasion in Australia. So yeah, that’s a good example. The key here for eco-evo dynamics is that it’s not just the trait that’s evolving, but that the evolution of that trait will have consequences for how many snakes are around. And that will also have implications for everything else that interacts with the snakes.
Andrew’s book is available here. Keep your eyes peeled for our next interview with Andrew, which will be focussed on advice for today’s undergraduate and graduate students.