As told to Boxoffice:
"Alien" just means that a species isn't native to a particular ecosystem. Most alien species are pretty benign, but there are a few that cause extreme harm, and those we call invasive species. They might be predators of other species, they might interfere with their reproduction, they may simply crowd them out.
Sometimes, these invasive species have no predators themselves—nothing eats them—so they really have an advantage. In Florida, there are these escaped Burmese Pythons—enormous snakes—and they're these big constrictors that grab a hold of their prey and slowly suffocate them. These things are eating a lot of animals, birds and mammals both. And there are thousands of them. They've called a 98.9% decline in small mammal populations in the Everglades because these foxes and racoons and opossums have never had to compete with a big snake before.
All species have a place. A Burmese Python in southeast Asia where they're native, they're fine. It's when they're moved to a place that isn't adapted to them that they cause trouble. I don't think of these snakes as evil-they're just out of place.
If you try to see Prometheus is the same way, it's a interesting science question. From the standpoint of us, their prey species, yeah, they're pretty evil. But from the standpoint of the alien, if human beings are what they need to reproduce, that's what they do. There's wasps like that—they lay their eggs and infect a caterpillar and then grown inside. Viruses are like that, too. From the standpoint of the aliens in Prometheus, we're just lunch.
When I was watching Prometheus, I was thinking about how there's a number of species that require others to reproduce, and when they're done, the whole other species is destroyed. Or when the snake-thing goes inside the guy's mouth, there's some live parasites like that. You don't have to go to another planet to find that. Especially the guy who had the little wormy thing in the pupil of his eye—there are parasites that will grow in a human being's eye.
And it's also true that there are species that can go quiescent for a long time as an egg or a spore, like those jar things that have been sitting there a very, very long time. When they sense movement, they activate and hatch. So that part of Prometheus strikes me as pretty realistic.
They key of dealing with invasive species is keeping them out, which is really the heart of Prometheus: you've got to keep them off Earth. Because once they're there, they can spread around of their own volition or through humans, kind of like what we saw with Noomi Rapace's boyfriend.
How would humans survive if that black goo had made it to Earth? Invasive alien species are especially big problems on islands. They can have a tremendous effect and actually cause the extinction of other species. And the biggest island we know of is Earth. Every year we have something that affects humans. Bird flu, swine flu, and then hopefully everyone gets a flu shot. There are a lot of people working to prevent another big flu epidemic like they had 100 years ago that some people estimate killed 50 million people. I don't think we have to worry so much about surviving the black goo from outer space—I hope not-but there are some fairly serious things happening today.
Prometheus happens here. Not big scaly monsters, but viruses. Look at zoonotic diseases that pass between humans and non-human animals, you have things like Ebola, SARS. And as we go into environments that human beings have not had a lot of contact with—like, say, the Rainforest or space—who knows what disease a monkey might have that could make a human being sick? We're doing an uncontrolled experiment and we're the white mouse.
But the thing about invasive species is it's really not about hating or being at war with them—it's about protecting the places that they impact. If you look at the Asian Carp in the Mississippi River, there's a lot of people working very hard to keep them out of the Great Lakes. But it's not because they hate these carp, it's because they're trying to protect the Great Lakes. And what I got from Prometheus is that it wasn't that they hated the black goo, they just wanted to protect the earth. That's what we try to do: protecting the earth is what we need to do to keep these great places great.
And in the film, I don't even know what the humans could have done to prevent everything that happened. It's difficult to know what a species will do when it's moved around, and we don't really know how many invasive species there are just here on Earth. But quarantine is a good step. If you have something that's been exposed to a pathogen and quarantine them while you're trying to figure out if they have it or not, that's a good first step. Even if you don't know if someone has been exposed, you treat them as if they are until it's confirmed that they haven't been.
The core truth of Prometheus is that people are afraid of parasites, of things that enter your body and take over. We're afraid of things that kill us outright, but we're especially afraid of something small and subtle that attacks you from within. There are human parasites that do that, like West Nile virus, which can make people very, very sick. That really speaks to a fundamental human fear of big things with small beginnings. And what can you do? When you don't have hospitals, you burn people with a flamethower like in the movie.
If I could give the crew of the Prometheus some advice before they headed into space, I'd say, "Don't go!" Or maybe, "Gosh, if you have all those good androids, why send a human?" No, if I could give them one piece of advice it would be that if you're going to a place that you strongly suspect is going to have life, you really, really need to think about cross-contamination. Like today, if we send a lander to Mars, we make sure it doesn't have Earth microbes on it. If there is something out there that could make us very, very sick, let's not take that chance. Let's keep it bottled up until we know what we have. So I guess my advice to the crew of the Prometheus is, "Listen to your biologist." Oh, and more flamethrowers.
Chris Diongi, Deputy Director of the National Invasive Species Council