A pictorial history of life on Earth, from exhibits at the Smithsonian Museum of Natural History in Washington DC.
![DSCN4209](http://farm6.staticflickr.com/5339/10008120993_db088a3143.jpg)
A fragment of the Murtchison meteorite, containing amino acids--the building blocks of life. About 4.5 billion years old.
![DSCN4467](http://farm8.staticflickr.com/7384/10008916323_f54622afd6.jpg)
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.
![DSCN4214](http://farm8.staticflickr.com/7417/10008028696_633b09e9f2.jpg)
Fossil stromatolite. Stromatolites are built up layer by layer, by bacteria. They have been found as far back as 3.5 billion years.
![DSCN4217](http://farm4.staticflickr.com/3804/10007936324_438807cdfc.jpg)
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.
![DSCN4216](http://farm4.staticflickr.com/3812/10007971465_2323134c59.jpg)
Dickensonia, another Ediacaran.
![DSCN4221](http://farm6.staticflickr.com/5517/10007980626_1e4ae3ddca.jpg)
A reconstruction of Ediacaran life.
![DSCN4399](http://farm8.staticflickr.com/7369/10006692624_e63b3b84b3.jpg)
Aysheaia, a wormlike creature from the Burgess Shale Fauna. Canada, about 520 million years ago.
![DSCN4401](http://farm8.staticflickr.com/7362/10009190274_84f39b89f6.jpg)
Marrella, a crablike member of the Burgess Shale Fauna.
![DSCN4454](http://farm4.staticflickr.com/3794/10008940886_3d11e12c61.jpg)
Wiwaxia, another Burgess Shale resident.
![DSCN4451](http://farm8.staticflickr.com/7425/10008914025_ee63f1581e.jpg)
Opabinia, an odd Burgess Shale animal with five large stalked eyes.
![DSCN4380](http://farm3.staticflickr.com/2891/10006898596_4bdb240f6e.jpg)
Crinoids, or "sea lilies", from the Ordovician period about 480 million years ago. They are animals, not plants.
![DSCN4385](http://farm8.staticflickr.com/7429/10006864076_6273a570f0.jpg)
Phacops, a common trilobite from the Devonian period around 350 million years ago.
![DSCN4233](http://farm4.staticflickr.com/3758/10007856005_055c572dba.jpg)
A fossil Eurypterid, known as "sea scorpions".
![DSCN4226](http://farm6.staticflickr.com/5550/10007946856_31a9dddbbd.jpg)
Reconstructed Euypterid, about five feet long.
![DSCN4393](http://farm3.staticflickr.com/2819/10006808846_4d19829cdd.jpg)
A reconstruction of Ordovician life, about 450 million years ago.
![DSCN4461](http://farm3.staticflickr.com/2843/10008854335_87ec9ef40c.jpg)
Dunkleosteus, a large placoderm fish from the Devonian period.
![DSCN4228](http://farm4.staticflickr.com/3822/10007933696_b24fdfe0c3.jpg)
Fossil Eusthenopteron, a lobe-finned fish that lived about 385 million years ago.
![DSCN4231](http://farm8.staticflickr.com/7306/10007841614_e301039818.jpg)
Reconstructed Eusthenopteron on land.
![DSCN4239](http://farm4.staticflickr.com/3802/10007859836_c14046d8a4.jpg)
Baragwanathia, an early land plant from the Devonian, 380 million years ago.
![DSCN4244](http://farm3.staticflickr.com/2879/10007754554_e2a56d9359.jpg)
Pelosaurus, an early amphibian.
![DSCN4259](http://farm6.staticflickr.com/5524/10007680665_4bc0e74e5c.jpg)
Eryops, a large amphibian from Texas, 270 million years ago.
![DSCN4267](http://farm4.staticflickr.com/3747/10007629885_75384f87fe.jpg)
Seymouria, an early reptile. 270 million years ago.
![DSCN4270](http://farm4.staticflickr.com/3764/10007610155_73238a36f2.jpg)
Fossilized eggs. The shelled egg allowed reptiles to reproduce on land.
![DSCN4271](http://farm8.staticflickr.com/7456/10007604345_5cf02f88d5.jpg)
Fossilized cycad plant.
![DSCN4285](http://farm3.staticflickr.com/2812/10007481964_a5c64bff3a.jpg)
Dimetrodon, a predatory reptile from the Triassic period. 280 million years ago.
![DSCN4287](http://farm6.staticflickr.com/5443/10007600733_f33113b1ab.jpg)
The name "Dimetrodon" means "two-measured teeth", and the differing tooth sizes show that it was an early ancestor of mammals.
![DSCN4288](http://farm3.staticflickr.com/2845/10007488065_2dea4dff97.jpg)
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 .
![DSCN4294](http://farm4.staticflickr.com/3698/10007550343_6ab518a97b.jpg)
Cynognathus, a mammal-like reptile from the Triassic period.
![DSCN4463](http://farm8.staticflickr.com/7416/10008940153_97c1161fff.jpg)
Ammonite. Marine relatives of squids, common in the Triassic and Jurassic.
![DSCN4428](http://farm8.staticflickr.com/7407/10009052265_926f65ed76.jpg)
Allosaurus, dinosaur from the Jurassic period. 150 million years ago.
![DSCN0361](http://farm5.staticflickr.com/4102/4744931396_b84d5d6356.jpg)
Stegosaurus, another Jurassic dinosaur.
![DSCN4369](http://farm8.staticflickr.com/7420/10006930685_b08e12060b.jpg)
Tylosaurus, one of the mososaurs--giant marine lizards from the time of the dinosaurs that were closely related to modern monitor lizards.
![DSCN4374](http://farm8.staticflickr.com/7354/10006895205_0f4fbe41a1.jpg)
Pliosaur, a short-necked version of the Plesiosaurs that were common in Mesozoic seas.
![DSCN4420](http://farm3.staticflickr.com/2845/10009199673_7da42eee53.jpg)
Fossilized eggs of Maiasaura in their nest.
![DSCN4366](http://farm3.staticflickr.com/2819/10006921434_5f5b980a21.jpg)
Hesperornis, a primitive toothed diving bird from the late Cretaceous. 75 million years ago.
![DSCN4416](http://farm8.staticflickr.com/7433/10009097514_de46227f30.jpg)
Edmontosaurus, one of the duckbill dinosaurs.
![DSCN4405](http://farm4.staticflickr.com/3763/10009166134_12b142658f.jpg)
Tyrannosaurus rex. Late Cretaceous.
![DSCN4364](http://farm8.staticflickr.com/7367/10006934554_632213805d.jpg)
Zygorhiza, an early whale. About 39 million years ago.
![DSCN4306](http://farm4.staticflickr.com/3735/10007336454_b44f640b85.jpg)
Uintatherium, a 30-million year old rhinoceros relative that lived in Wyoming.
![DSCN4309](http://farm6.staticflickr.com/5465/10007389716_6a949a00ab.jpg)
Orohippus, an early horse from North America.
![DSCN4313](http://farm3.staticflickr.com/2812/10007315565_d621bce38a.jpg)
Diatryma, one of the large "terror birds" that lived in North America during the Miocene period.
![DSCN4317](http://farm4.staticflickr.com/3787/10007336306_90c5e63064.jpg)
Smilodectes, a lemur-like primate that lived in Wyoming. About 55 million years old.
![DSCN4361](http://farm4.staticflickr.com/3729/10007029006_9f10e836eb.jpg)
Acrophoca, an early seal. Lived about 10 million years ago. Found in marine deposits in Peru.
![DSCN4465](http://farm4.staticflickr.com/3803/10008927713_a66b00f0b6.jpg)
A fossilized Jack fish from Italy, Eocene era.
![DSCN4346](http://farm4.staticflickr.com/3780/10007091765_6391936ea5.jpg)
Megatherium. A giant ground sloth that lived in North and South America during the Ice Age.
![DSCN4351](http://farm8.staticflickr.com/7308/10007057475_65c204a4b8.jpg)
Wooly Mammoth. About 10,000 years ago.
![DSCN4356](http://farm3.staticflickr.com/2856/10007128983_cc772a8e9b.jpg)
Mastodon. While mammoths were grazers who lived on plains and tundra, mastodons were browsers who lived in forested land.
![DSCN4358](http://farm8.staticflickr.com/7307/10006977924_e3d67e9730.jpg)
Glyptodont. An armored relative of the armadillo.
![DSCN4334](http://farm8.staticflickr.com/7412/10007220596_b485032b66.jpg)
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.
![DSCN4347](http://farm4.staticflickr.com/3716/10007131436_73ec52523e.jpg)
Smilodon, the Saber-Toothed Cat.
![DSCN4494](http://farm3.staticflickr.com/2813/10008652445_cd8a49499b.jpg)
Sahelanthropus, the earliest known hominin. 7.65 million years ago.
![DSCN4497](http://farm3.staticflickr.com/2865/10008634455_841e55438b.jpg)
Kenyanthropus. 3.5 million years.
![DSCN4501](http://farm8.staticflickr.com/7336/10008610895_9202473147.jpg)
Australopithecus afarensis. 3 million years.
![DSCN4533](http://farm4.staticflickr.com/3708/10008517353_5b8fb7750c.jpg)
A afarensis, "Lucy".
![DSCN4505](http://farm4.staticflickr.com/3699/10008588315_51055fe291.jpg)
Australopithecus africanus. 2.5 million years.
![DSCN4509](http://farm4.staticflickr.com/3790/10008566495_fa57a2cd4f.jpg)
Homo habilis. 1.8 million years.
![DSCN4511](http://farm4.staticflickr.com/3755/10008554175_6c00ac2394.jpg)
Homo erectus. 1.8 million years.
![DSCN4521](http://farm8.staticflickr.com/7447/10008591993_4495db5bd3.jpg)
Homo heidelbergensis. 450,000 years.
![DSCN4527](http://farm4.staticflickr.com/3749/10008497426_e239808e94.jpg)
Homo neandertalensis. 200,000 years.
![DSCN4537](http://farm8.staticflickr.com/7321/10008436136_fd9c49292a.jpg)
Homo erectus and Homo neandertalensis.
![DSCN4535](http://farm4.staticflickr.com/3686/10008448596_e95aa1b950.jpg)
Oldowan stone tool, the first hominin technology. 1.8 million years ago.
![DSCN4532](http://farm8.staticflickr.com/7440/10008424955_72064a6bb4.jpg)
Stone hand axes.
![DSCN4484](http://farm6.staticflickr.com/5515/10008759036_09b9dd6877.jpg)
Flute carved from Mammoth ivory. 35,000 years old, from Germany.