For one monstrous parasitic flower, it is reeking of rotten meat; among other odd creatures, it is a wide array of otherworldly adaptations that allow them to survive the most extreme conditions found on Earth. All of the organisms in the American Museum of Natural History’s Life at the Limits exhibit, however, can be said to have superpowers.
Organized by categories such as breathing, eating and reproduction, the organisms included in Life at the Limits, which opens April 4th at the American Museum of Natural History in New York City, represent the extreme ends of the normal evolutionary spectrum for particular traits. Scientific American spoke with exhibit co-curator Mark Siddall, a curator in the museum’s Division of Invertebrate Zoology, about how the exhibit is designed with make it relevant to visitors as it reframes extreme traits as normal and shows why the present is a great time to study biodiversity.
[An edited transcript of the conversation follows]:
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By what measures are the organisms featured in this exhibit extreme?
To the extent that it was possible, we wanted to make sure that the visitors who come here would find their own place in it. Take an intrinsic biological factor that we all deal with: reproduction. It turns out that humans, for example, are incredibly extreme when it comes to reproduction. We make one or two offspring usually in an event, and they can’t walk for a year. Or if you look at how we move around, there are actually more mammals [five] that lay eggs than there are mammals that walk on two legs. But then in other respects, such as the decibels that we hear, the light frequencies that we see and where we live in terms of temperature and pressure, we’re kind of a middling species.
You can take any parameter—it can be a biotic parameter such as speed, strength or size, or a physical parameter such as temperature, light spectrum or altitude—and there is a distribution within which life exists. There’s enormous diversity within each of these parameters both because of the different environments in which life lives and the intrinsic properties of organisms themselves.
In what ways are they also normal?
A “normal” mathematical distribution is a bell-shaped curve. You can pick any parameter and find something at either end of it. So the things that are at the end points—the upper and lower limit of that normal distribution—they’re normal! They’re just not in the middle where most other things are. What we’re trying to get at here is that they tend to be fewer in number, very highly specialized and in a sense “super” relative to other organisms in the distribution of life.
What does this mean for looking for life on other planets?
When we get a sense of the diversity of life contained this thin layer of biosphere on our planet, it opens up an understanding that there are a lot of possibilities for where we might find life—if we could recognize it. Life as we understand it is at least liquid-based, so things can move around. And if movement is part of life, then some form of liquid, not necessarily water, has to provide that fluidity that allows life to move around. When you look at things like caves and deep-sea hydrothermal vents, it shows that life can exist in the absence of light, and that a planet doesn’t have to be in the same sort of zone around its sun that our Earth is in order to host life.
How much biodiversity has still yet to be studied on Earth?
There’s so much left to study, not even just in extreme environments. We’re still getting a handle on the biodiversity in the Congo Basin. We haven’t really got a good handle on the sheer diversity of life in all the ranges of depths in the ocean. We know a lot about what’s really deep and what’s really shallow but there’s that mid-range that constitutes the majority of the ocean where there’s certainly a lot left to discover. So there’s tons left to do all over the place.
What do you want visitors to take away from this exhibit?
Just the sheer fascination with the diversity of life in form, in behavior, in ability and to feel special to be able to witness it, both in terms of our living on this planet at a time when there’s tremendous diversity and, I think, a sense of custodianship where we have a sense of responsibility both to understand and to preserve.
In what ways are we living in “a time when there’s tremendous diversity”?
Immediately after the Permian mass extinction and other mass extinctions there was a lot less diversity. There’s a lot of diversity out there right now and we have a wide range of environments—from freezing environments to hot environments to desert environments and so on—so it is really a time of tremendous diversity on the planet. When I was a kid, I said, “Wow, wouldn’t it be great if I lived in a time when there were dinosaurs?” Do you know that you’re living at the time when the largest animal to ever live—the great blue whale—actually lives on the planet? That’s pretty awesome.