Welcome to today’s lesson. We’re continuing with our study of taxonomy. Taxonomy is how scientists classify organisms into different groups based on the characteristics that they share. So, for instance, a good way to think about taxonomy is the US Postal Service. If we want to send a letter to someone, we first start off by addressing it to the nation they are in. By default, we usually assume that’s America but it doesn’t have to be, could be England or Costa Rica or Spain. You put their nation or their kingdom. Then within that kingdom, you address it to a slightly more specific level, their states. So, for instance, South Carolina would be the same as a phylum（门）. And within that state, you would address it to their city and then to their street number, the street they live on. Then you would address it to say their apartment complex and within that complex, you’d address it by their last name to their family and then finally their first name to the specific person you want to get it to, and in that way, we’re able to weed out all the 400 million people we don’t want to send our letter to in America and pinpoint the exact person we want the letter to reach. And in the same way scientists use a taxonomy chart to pinpoint a living creature and organism and how it relates to everything else in the world.