Figure 1 description

A phylogenetic tree illustrating the evolutionary relationships among several groups of animals. At the root is an hypothetical ancestor, about 550 million years ago

• 0.1
  • 0.1.1 Molluscs
    • 0.1.1.1
      • 0.1.1.1
        • 0.1.1.1.1 Gastropods with a picture of a snail
        • 0.1.1.1.2 Cephalopods
          • 0.1.1.1.2.1 others
          • 0.1.1.1.2.2 Coleoids with pictures of an octopus, a cuttlefish, and a squid and highlighted to indicate a commonly studied group of animals
        • 0.1.1.1.3 Bivalves with a picture of a clam
        • 0.1.1.1.4 others
      • 0.1.1.2 Chitons with a picture of a chiton
    • 0.1.2 others
  • 0.1.2
    • 0.1.2.1 Arthropods with a picture of a lobster
    • 0.1.2.2 others
• 0.2
  • 0.2.1 Echinoderms with a picture of a starfish
  • 0.2.1 others
  • 0.2.3 Vertebrates, approximately 300 million years ago
    • 0.2.3.1 fish with a picture of a bony fish
    • 0.2.3.2
      • 0.2.3.2.1 Amphibians with a picture of a frog
      • 0.2.3.2.2
        • 0.2.3.2.2.1
          • 0.2.3.2.2.1.1 Birds
            • 0.2.3.2.2.1.1.1 Corvids with a picture of a Eurasian jay and highlighted to indicate a commonly studied group of animals
            • 0.2.3.2.2.1.1.2 others
          • 0.2.3.2.2.1.2 Reptiles with a picture of a sea turtle
        • 0.2.3.2.2.2 Mammals
          • 0.2.3.2.2.2.1 Great apes with a picture of a chimpanzee and highlighted to indicate a commonly studied group of animals
          • 0.2.3.2.2.2.2 others