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REDIRECT → Invertebrates → Fish
An invertebrate is an animal without a backbone. Invertebrates are among the
Fish and Invertebrates
most common animals, making up 97% of all animal species. Vertebrates are largest group of chordates, and contain over 50,000 species, including jawless fishes, bony fishes, sharks, and amphibians, reptiles, mammals and birds. The oldest vertebrates include fish, which evolved during the Cambrian Period, 510 MYA.