How much biodiversity do we really know?

(soft music) - How much do we really know about biodiversity? That's a really open-ended question, it's like a question on a final exam in a school kid's nightmare, list in alphabetical order the things that mankind does not know. Hm. But for a very real question, there are people who are trying to bring a scientific angle to answering this mystery of what we do not know about biodiversity. How can we estimate what we don't know? How many unknowns are still out there? What is there left to discover? So, the question is, what is the species richness of the planet? That's really the problem that people are trying to address when they're asked how many species are there on earth? And how many of them have you named? It boils down to this question of what happens if we go out to any given environment and look around? How many of the things that we discover there could we actually put a name to so that we could go back and talk to people about 'em say, we've discovered 600 species of insects, 800 species of flowering plants, et cetera, et cetera, et cetera. And then make a list of those names. It's been said lots of times that attempts to record and understand biodiversity go back. Actually, I would say myself, to the start of human language. Because humans who were grunting around to each other back then had to communicate, watch out man, that thing'll eat us. Or, that thing is good to eat. We need to make those distinctions. That's pretty basic, but also essential taxonomy. That's knowing something about your environment. That's knowing some of the biodiversity right there. So, the first words probably expressed meanings along those lines. The impetus for developing a language was probably not going to get any stronger than describing the biodiversity of whatever was chasing you through the forest or, don't eat the green ones. That's taxonomy. That's knowing biodiversity. The written records of describing biodiversity start with Plato, a Greek who lived 428 to 350 years before the current era. Plato tried to deal with and describe the complexity that you see in the natural world by coming up with a concept called, essentialism. Essentialism was the idea that species and forms in nature were less than perfect expressions of some ideal form. There was a design for every single type of thing and each of these things had deep essences, some mysterious property that allowed them to be what they were. Not a very scientific idea, but it was a definite expression again of, okay ,that's why there are types of animals. That's why there are snails and sea urchins, and fish. Plato had a very clever and ultimately famous student named Aristotle, who's generally felt to be the originator of the study of Biology. He wrote very precise works aimed at the study of animals. The Historia Animalium is among these. It had several different parts dealing with the philosophy of why there are different essences and different things out there. Why they could or could not change from one thing to another. Aristotle's ideas about animals were arranged on what became known as the Ladder of Creation. Or the Ladder of Nature. The Scala Naturae. Scala means ladder and Naturae is of nature. So this ladder was a system that Aristotle set up to allow him to communicate about the diversity of life on earth. But there was no change over time, things could not evolve from one thing into another. They were pearls on a string, just touching but not changing. The Middle Ages are known as dark times when people were dealing with horrible stuff going on. But in reality, in between wars and disease the most learned people at the time were busy writing books. Sometimes listing things that they knew about nature. These were called, Bestiaries. And were driven by the need of religious leaders to help communicate Godly designs and moral lessons to their congregations. For example, particularly slow moving organisms were lessons in laziness. Or industrious organisms were lessons in, yeah, you gotta get out there and do your thing. So go pollinate that flowers. Be a bee. You know, build a dam and be like the beaver. Bestiaries are important, sometimes accurate, deceptions of things like hippos and rhinoceroses. But reality was no barrier to these early authors. You also had unicorns and sea serpents to round out the stories. It wasn't really until a few hundred years ago that people started trying to figure out the science of these things. Our old friend Linnaeus for example, really got down to the business of designing a system of consistently naming and describing things. So, what's different today? We have a variety of technologies that speed up the process of determining what biodiversity is out there. For example, we have remotely operated submarines that go deep into the Ocean. Big expeditions that discover new forms, and molecular techniques that look just for different kinds of DNA. Even when the whole organism hasn't even been found yet. All kinds of interesting ways of going out and trying to find things out about biodiversity. Ways of trying to assess the total number of organisms out there. Even as recently has 2010, researchers interested in figuring out how many species existed on earth, used all the specimens in information they were gathering, they looked at published literature, and talked to different experts. And they discovered that the best guesses so far were between 3,000,000 and 100,000,000 species on Earth, and that's a pretty broad range. But in a paper published by Camilo Mora and Colleagues, in 2011, a series of mathematical models were developed to estimate the total number of species on earth. The models were based on the rates at which species were being discovered in different groups of organisms, and how they were arranged in taxonomic categories. From Phylum down to Species. Mora's group estimated that there are about 8.7 million species. But there's an error margin on that, so it could be anywhere from about 8.1 or 8.2 to almost 9,000,000 overall. Still a broad range, but at least it narrowed it down. We currently have about 1.2 million species named and described. So, with Mora's estimate, we're looking at a whopping 80 to 90% of what we think is out there as still waiting to be discovered, even after 250 years of work on the problem. We now have an estimate of the scale of what we don't know. And that's a big part of the problem figured out. We know a lot more about some environments than others. The number of species that we know from a relatively remote piece of rainforest is probably going to be a lot lower than in say, a desert, or an area that's easy to get to. Where it's relatively easy to see all of the things that are there. Another example, we've only explored about 5% of the ocean bottom. Most of that's really dark and the deepest bits are pretty hard to get to. It's not easy to document life in the deep sea. It sounds weird to say it but in some ways, the more we know, the less we know. Because the more we know about how to sample DNA, the more types of organisms we can find and say, a vial of sea water. Or a handful of soil. Just by sampling the DNA and separating out all of the different types of DNA that are there. So, with the sheer size of that task at hand is it even possible to make proper decisions about how to preserve biodiversity? It might seem hopeless. Why do we bother to do this? Well, ultimately there's as many good reasons to do it as there are species on Earth. We need to know what's there in order to know what to save. Even if we only know 10%, that's still 10% more than we know at the beginning, right? And that percentage is growing, slowly but surely. And each new species is telling us something new. Something crucial about life's diversity. Plus, going back to my opening reference to a nightmare of a final exam question, if you're going to use what we know now to make predictive models about what we don't know, then the more you know, the more accurate the prediction is going to be. I think it's kind of like being a hockey coach. If you know the names of only 10% of your players, how effective a coach are you gonna be? How are you gonna yell instructions to those guys out there on the ice? How are you gonna control the pace of the game and communicate strategies or even know who's in the penalty box? To understand the game, you've gotta know all the players, all their positions, and how good they are. In short, as much as possible about them. Similarly, to understand biodiversity and healthy ecosystems, we need to know as many of the biodiversity players as possible and what they do. Clearly, there's a lot of work left to do and there are not that many professionals systematics. It's why we need the help of many different technologies and approaches. And we also need the help of interested people who are not scientists. Anyone can help. We need more people. Citizen scientists going out and exploring, and discovering, and communicating their findings to scientists. This is what humans have been doing since the dawn of time when we were pushed to understand and communicate about biodiversity in the environments around us. We're still driven to discover and talk about biodiversity because the need has never been more urgent for our survival.