How many living things can you name and how many names do you know for different types of living things? One of the goals of biology is to name and classify all living things on Earth. Unfortunately, we're still a long way from fulfilling that goal. Still, most of the plants, animals, and other organisms that are familiar to us have formal scientific names. In modern biology, scientists use a binomial or two-word, naming system for all living things. We humans are Homo sapiens. Homo is the genus or the general group to which we belong. The word Homo comes from the Latin word for human, and within that group our species is sapiens, meaning wise, so we call ourselves the wise humans. That's a nice idea, even if we don't always live up to our name. The person who's responsible for this naming system was Carl Linnaeus. He was a Swedish botanist who revolutionized not only the system we use for naming species but also the way that we classify them. Linnaeus didn't start his career with the goal of transforming our system of naming and classifying species, but a trip he took as a young man led him down a completely different path. In 1732, at the age of 25 Linnaeus set out on an expedition. He left the town of Uppsala, Sweden, where he had been teaching classes on botany and headed North into the remote frontier region known as Lapland. He spent six months exploring and collecting specimens of plants, animals, and minerals, many of which were not yet formally known to the scientific community. Those that were had long, cumbersome names. To make matters worse, the names being used were easily confused by people from different regions or that spoke different languages. Linnaeus journey wasn't an easy one, and he relied on help along the way from local people known as the Sami. Like indigenous people around the world, the Sami knew their homeland very well having lived there for thousands of years. When Linnaeus would find a new plant that was unfamiliar to him, his Sami companions would tell him the name that they used for in their language as well as any uses that it has. Linnaeus recorded these names in his notebook along with his own notes about where it lives and any other observations he could make. He collected specimens of every living thing that he could find, and after six months, he returned home to make sense of his collection. As he sorted through all of the plants and animals he had collected in Lapland Linnaeus began assigning names to every species. He assigned each a Latin name, distinguishing them based on characteristics like the male and female parts of flowers, but he kept the Sami tradition of using two names, both a genus and species for each unique type. Linnaeus system would eventually be adopted by biologists everywhere. The fact that we use a binomial system for naming all living things owes its origin not only to Linnaeus but also to the Sami people. But his trip to Lapland was just the beginning of Linnaeus's ambitions. Based on his collections, it seemed possible that if he continued collecting, naming, and cataloging specimens the same way, he could eventually document all the species in Sweden and, if he could get enough specimens, perhaps even the entire world. Linnaeus sent students out on expeditions to collect plants and animals around the globe. Unfortunately, he wasn't very good about giving his students credit for their efforts. Linnaeus would give a Latin name to each new species that his students had collected, adding his own name to the end to indicate that he was the person who had documented it. Linnaeus' quest to name and classify every species on Earth was certainly ambitious, but Linnaeus had no way of knowing how unrealistic this goal was. The fact that his first major effort to describe the flora and fauna of a particular region took place in Northern Sweden, above 60 degrees latitude and partially inside the Arctic Circle was an important detail. We now know that as you get closer and closer to the North or South Pole, the number of species that exist in a particular area declines. Humboldt had noted this based on his own experiences, finding far more species in the tropical regions near the equator than in the higher latitudes of Europe. Humboldt had also noted that the number of species declines as you move up in altitude along a mountain slope in much the same way as when you move up in latitude. But Humboldt's observations wouldn't come until the early 1800s. Back in the 1730s, Linnaeus and other European scientists were unaware of just how rich the Earth is in biological diversity. This was largely because the places where the European scientists had done most of their collecting were nowhere near as diverse as the lower latitudes. Even though Linnaeus sent students to places like Brazil to collect specimens, it was difficult for him to get a sense for the fact that what they brought back was just a tiny sliver of the biologically rich tropics. For Linnaeus, this meant that he would not succeed in his quest to name and classify all life on Earth, but he did have a lasting impact on the ability of other scientists to make sense of the diversity of life. We still use both his naming and classification system today. For our purposes, it's worthwhile thinking about why it is that some regions, like high latitudes and the tops of mountains, have fewer species and why other regions, like the tropics, tend to be so biologically diverse. In fact, this is a central question in the field of ecology. What factors determine how many species and which species live in a particular place? As we'll see, finding answers to this question is both complicated and fascinating and has occupied generations of ecologists.