Planet of the scum. The first fossils : Cryptozoon -- Garden of Ediacara. The first multicellular life : Charnia -- "Little shellies." The first shells : Cloudina -- Oh, give me a home, when the trilobites roamed. The first large shelled animals : Olenellus -- Is it a worm or an arthropod? The origin of arthropods : Hallucigenia -- Is it a worm or a mollusc? The origin of molluscs : Pilina -- Growing from the sea. The origin of land plants : Cooksonia -- A fishy tale. The origin of vertebrates : Haikouichthys -- Mega-jaws. The largest fish : Carcharocles -- Fish out of water. The origin of amphibians : Tiktaalik -- "Frogamander." The origin of frogs : Gerobatrachus -- Turtle on the half-shell. The origin of turtles : Odontochelys -- Walking serpents. The origin of snakes : Haasiophis -- King of the fish-lizards. The largest marine reptile : Shonisaurus -- Terror of the seas. The largest sea monster : Kronosaurus -- Monster flesh-eater. The largest predator : Giganotosaurus -- Land of the giants. The largest land animal : Argentinosaurus -- A feather in stone. The first bird : Archaeopteryx -- Not quite a mammal. The origin of mammals : Thrinaxodon -- Walking into the water. The origin of whales : Ambulocetus -- Walking manatees. The origin of sirenians : Pezosiren -- Dawn horses. The origin of horses : Eohippus -- Rhinoceros giants. The largest land mammal : Paraceratherium -- The ape's reflection? The oldest human fossil : Sahelanthropus -- Lucy in the sky with diamonds. The oldest human skeleton : Australopithecus afarensis -- Appendix. The best natural history museums.