A pictorial history of life on Earth, from exhibits at the Smithsonian Museum of Natural History in Washington DC.
A fragment of the Murtchison meteorite, containing amino acids--the building blocks of life. About 4.5 billion years old.
Banded iron formation. The appearance of oxygen in the atmosphere as a result of photosynthetic bacteria caused iron in the oceans to oxidize, forming these banded iron deposits. 3.7 billion years ago.
Fossil stromatolite. Stromatolites are built up layer by layer, by bacteria. They have been found as far back as 3.5 billion years.
Ediacara flindersi, a fossil jellyfish-like organism, and namesake for the Ediacaran fauna, the earliest known multicellular life. Found in Australia. 600 million years old.
Dickensonia, another Ediacaran.
A reconstruction of Ediacaran life.
Aysheaia, a wormlike creature from the Burgess Shale Fauna. Canada, about 520 million years ago.
Marrella, a crablike member of the Burgess Shale Fauna.
Wiwaxia, another Burgess Shale resident.
Opabinia, an odd Burgess Shale animal with five large stalked eyes.
Crinoids, or "sea lilies", from the Ordovician period about 480 million years ago. They are animals, not plants.
Phacops, a common trilobite from the Devonian period around 350 million years ago.
A fossil Eurypterid, known as "sea scorpions".
Reconstructed Euypterid, about five feet long.
A reconstruction of Ordovician life, about 450 million years ago.
Dunkleosteus, a large placoderm fish from the Devonian period.
Fossil Eusthenopteron, a lobe-finned fish that lived about 385 million years ago.
Reconstructed Eusthenopteron on land.
Baragwanathia, an early land plant from the Devonian, 380 million years ago.
Pelosaurus, an early amphibian.
Eryops, a large amphibian from Texas, 270 million years ago.
Seymouria, an early reptile. 270 million years ago.
Fossilized eggs. The shelled egg allowed reptiles to reproduce on land.
Fossilized cycad plant.
Dimetrodon, a predatory reptile from the Triassic period. 280 million years ago.
The name "Dimetrodon" means "two-measured teeth", and the differing tooth sizes show that it was an early ancestor of mammals.
Lystrosaurus, one of the few survivors of the Permian extinction event, 252 million years ago, that wiped out over 90% of all life on Earth .
Cynognathus, a mammal-like reptile from the Triassic period.
Ammonite. Marine relatives of squids, common in the Triassic and Jurassic.
Allosaurus, dinosaur from the Jurassic period. 150 million years ago.
Stegosaurus, another Jurassic dinosaur.
Tylosaurus, one of the mososaurs--giant marine lizards from the time of the dinosaurs that were closely related to modern monitor lizards.
Pliosaur, a short-necked version of the Plesiosaurs that were common in Mesozoic seas.
Fossilized eggs of Maiasaura in their nest.
Hesperornis, a primitive toothed diving bird from the late Cretaceous. 75 million years ago.
Edmontosaurus, one of the duckbill dinosaurs.
Tyrannosaurus rex. Late Cretaceous.
Zygorhiza, an early whale. About 39 million years ago.
Uintatherium, a 30-million year old rhinoceros relative that lived in Wyoming.
Orohippus, an early horse from North America.
Diatryma, one of the large "terror birds" that lived in North America during the Miocene period.
Smilodectes, a lemur-like primate that lived in Wyoming. About 55 million years old.
Acrophoca, an early seal. Lived about 10 million years ago. Found in marine deposits in Peru.
A fossilized Jack fish from Italy, Eocene era.
Megatherium. A giant ground sloth that lived in North and South America during the Ice Age.
Wooly Mammoth. About 10,000 years ago.
Mastodon. While mammoths were grazers who lived on plains and tundra, mastodons were browsers who lived in forested land.
Glyptodont. An armored relative of the armadillo.
Skull of North American Lion, which lived in the US after the Ice Age, about 12,000 years ago. It was 50% bigger than the modern African Lion.
Smilodon, the Saber-Toothed Cat.
Sahelanthropus, the earliest known hominin. 7.65 million years ago.
Kenyanthropus. 3.5 million years.
Australopithecus afarensis. 3 million years.
A afarensis, "Lucy".
Australopithecus africanus. 2.5 million years.
Homo habilis. 1.8 million years.
Homo erectus. 1.8 million years.
Homo heidelbergensis. 450,000 years.
Homo neandertalensis. 200,000 years.
Homo erectus and Homo neandertalensis.
Oldowan stone tool, the first hominin technology. 1.8 million years ago.
Stone hand axes.
Flute carved from Mammoth ivory. 35,000 years old, from Germany.