As far back as the 19th century it was apparent to some biologists that a simple, repeated pattern underlay the differing body structures of animals. It could be seen in the segmented bodies of worms, ...

Common dolphin off the coast of Australia. This species lives in the open ocean, can reach high swimming speeds, has more than 70 vertebrate and up to eight regions in their backbone. If you’ve ever ...

Yes and no: It depends on how you classify animals. There are two main classification systems – the Linnaean system which groups organisms by characteristics and the phylogenetics system, which ...