human
I'd like to learn about the different types of animals in the world.
assistant
The number of species on Earth is estimated at between 5 and 30 million, with over 1 million being insects alone. Animals are classified into two major groups, vertebrates (including humans) and invertebrates. Invertebrates include everything from worms to insects to spiders to molluscs. Vertebrates include all mammals, birds, reptiles, amphibians, fish, and even some plants. There are also many other animal phyla that have not been classified yet.