Most users of the tree structure service need only concern themselves with a single numeric parameter, node_id, which is the unique identifier for a group in the ToL database. In order to download the structure for the entire tree use node_id=1, which is the node id for Life on Earth. The ids of other named nodes may be obtained via the ToL Group ID Service (see above). If a named node ... has a ToL branch or leaf page attached to it, you can also get its id from the page url. In ToL page urls, the node id will usually be appended at then end, separated by a slash from the group name. For example, the url for the Bembidion page is: