Scientists have developed various systems of classification to describe living things. The one used here is a cladogram, which is a diagram that shows the relationship between different species of animal. Each branch of the cladogram is a clade, which includes an ancestral species and its descendants, showing how a particular group of dinosaurs evolved. Each clade of dinosaurs shared certain characteristics – perhaps they looked alike, moved in a similar way, or had the same habits or lifestyles.
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