 All living things are grouped into five kingdoms. And in this video, we're going to look at the animal kingdom in more detail. Before we start, you may want to watch our video on classifying organisms first to remind yourself of kingdom, filler, class, order, family, genus and species. They are thought to be over 7.5 million species of animal on planet earth, of which 900,000 have been described. These are arranged into over 30 filler, of which these are the 9 most common. And these 5 are the 5 main animal filler. Arthropods, Analyz, Molysk, Nematodes and Cordot make up a rhyme or acronym to help you remember them. Aunty Anne makes nice cakes, A-A-M-N-C. A big question to ask is, do they have a backbone? If yes, they are a vertebrate, if no, they are an invertebrate. This can be tricky to remember. I always think of no backbone as long as to say then backbone. So no backbone must be invertebrate and backbone is just a vertebrate. All of these are invertebrates, and just these here, the cordata, contain all of the vertebrates. Not all cordates are vertebrates, but all vertebrates are cordate. Let's have a look at the vertebrates in more detail. There are many different classes of vertebrate, but the 5 most well known ones are the fish, birds, amphibians, mammals and reptiles. Again make up a little acronym to help you remember. Farmer Bob ate marmite rolls. Each class has different characteristics that defines them. Like mammals, which have fur or hair, feed their young on milk and are warm-blooded. Pause the video and have a look at what the difference is for each of these 5 common vertebrate classes. Sometimes people aren't too sure whether something is a reptile or an amphibian. Reptiles have scaly skin, breathe air and usually live on land, except for turtles. Amphibians live double lives. They start in the water and breathe gills and as they grow older they develop lungs. Once inside a class, so mammals for example, different species are grouped together in even more detail. There are about 5,000 species of mammals classified into 3 subclasses and about 26 orders. So that's the vertebrates. Now for the invertebrates. Let's go back to our 9 filler. And the 5 main ones, remember Aunty Anne makes nice cakes. Let's have a look at arthropods in a little more detail. They all have a hard exoskeleton and have jointed legs. See how diverse they are? Notice how spiders are not insects, but they are a different class of arthropods altogether called arachnids. And just like in animals, these classes break down even further, like for insects. So from this video, you should now know that the animal kingdom breaks down into over 30 filler, with these as the main 5. And then these filler break down into more detail. The cordata include all vertebrates, which in itself breaks down into lots of different classes including these 5.