This interactive tree diagram displays a hierarchical classification of animals, with branching categories for vertebrates and invertebrates. The visualization uses D3.js to render an SVG layout with collapsible nodes, where clicking a node toggles its children in an animated transition. Data is loaded directly from a static JavaScript object, while the tree layout and diagonal link projections come from D3’s layout library. The animation updates node positions smoothly over a set duration, with circles and styled text labels for each species.