The Ocean Through Time

Life began in the ocean around 3.5 billion years ago and as evolution progressed, many species went extinct -- and some left behind fossils -- as others appeared. And even now, the ocean hasn't stopped changing as evolution continues and humans leave their mark.

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Elevator Rudists

May 1, 2013 - 9:48AMThese "elevator" rudists, an ancient bivalve, used one long heavy valve to anchor themselves in the sediment. They used their tentacles (shown here in pink) to filter food from the sea water. Discover more about the ancient...

Teeth and Jaw of an Ancient Shark
Mar 21, 2013 - 9:20AM
This well-preserved fossil is the only intact partial skull ever found of a...

Megalodon Teeth
Feb 26, 2013 - 10:35AM
Two fossilized teeth from a megalodon (Carcharodon megalodon) dating back...
The Whale Family Tree
Jan 26 2010 - 11:45am
This family tree shows how the ancestors of whales moved gradually from land to sea. Early whales took advantage of abundant marine resources. Baleen whales evolved later as polar climates cooled and marine resources became more concentrated, making filter feeding effective. Learn more at "Did...
A Squalodontid Success
Jun 22 2011 - 5:47pm
On a beach in Piña, Panama the tide is rolling out. Faint outlines of skeletal remains rise above the sand. Smithsonian scientists Nicholas Pyenson and Aaron O'Dea along with a team of students descend upon the beach. Their mission: to excavate the remains of a whale from the extinct group...
Dislodging the Fossil
Jun 22 2011 - 4:05pm
Paeleobiologist Dr. Nicholas Pyenson, Curator of Fossil Marine Mammals for the Smithsonian's National Museum of Natural History (NMNH), set out with Jorge Velez-Juarbe, NMNH Research Student and Ph. D. Candidate at Howard University and Aaron O'Dea from the Smithsonian Tropical Research Institute...
Illustration of Helicoprion
Jan 26 2010 - 11:45am
This illustration shows one old idea of what the ancient shark Helicoprion might have looked like. There was room for many ideas—some more plausible than others—because the only fossils of the fish were of a strange, spiral-shaped jaw loaded with teeth. Where did it go? In its mouth, on its nose,...
Smithsonian Paleobiologist Brian Huber
Smithsonian Paleobiologist Brian Huber
Mar 26 2010 - 1:09pm
Brian Huber studies fossil organisms known as “forams” to learn about climate change in this video snippet from the Smithsonian Marine Collections video.
Ancient Sea Cow Vertebra
Jun 18 2011 - 10:06am
A fossil vertebra that a Smithsonian researcher's mother found while prospecting in the Gatun Formation. It's not just any vertebra, it belongs to a fossil sea cow! According to Jorge Valez-Juarbe, a graduate student at the Smithsonian's National Museum of Natural History and expert on fossil sea...
Foraminifera
Mar 25 2010 - 4:23pm
Microscopic, single-celled organisms called foraminifera have a fossil record that extends from today to more than 500 million years ago. Although each foram is just a single cell, they build complex shells around themselves from minerals in the seawater. These shells have accumulated in layers of...
Bringing sediment core on ship
Mar 23 2010 - 12:02pm
Researchers bring a sediment core dug from the seafloor off the coast of Panama onto the deck of a ship. Cores like these are shedding light on what Earth’s climate was like in the past. More about climate change can be found in our climate change featured story.
Evolution of Whales Animation
Evolution of Whales Animation
Sep 30 2009 - 11:21am
Whales have existed for million of years. Watch this animation, from the Sant Ocean Hall, to see how they evolved from land-dwellers to the animals we know today. Discover more about whale evolution in our Ocean Over Time interactive. Note: this video contains no audio.
Expedition to Excavate a Fossil Whale
Jun 17 2011 - 11:03am
My graduate student Jorge and I are departing today for Panama, to excavate a fossil whale that was discovered by an undergraduate student working with Smithsonian Tropical Research Institute researcher Aaron O'Dea.
Really Small Fry Shifting Baselines in Marine Fish Stocks
Really Small Fry: Shifting Baselines in Marine Fish Stocks
Dec 4 2009 - 1:06pm
A public service announcement uses a dramatic example to emphasize that ocean fish aren’t as big as they used to be. Find out more about the decline in the ocean's top -- and often large -- predators in a recorded talk by marine ecologist and National Geographic explorer Enric Sala.
Ancient Great White Shark
Jan 26 2010 - 11:45am
A scientific illustration of the most powerful fish of its time, Carcharodon megalodon, which swam the ocean 30 million years ago.  This shark may have reached a size of 20 meters/66 feet. Meet other ancient top predators and modern great white sharks.
Rudist Reefs
Dec 4 2009 - 3:25pm
About 100 million years ago, during the heyday of the dinosaurs, reefs were built by mollusks called rudist clams. They looked very different from today's coral reefs.
Top Predators Timeline
Sep 24 2010 - 6:00pm
What makes a top predator? Razor-sharp teeth? Speed? Strength? Size? Who is the most fearsome hunter? It depends on where and when you look.
Shark Ancestors
Dec 17 2009 - 6:55pm
Long before great white sharks appeared, much larger ancestors roamed the ocean. This giant ancient shark -- the Giant Megatooth (Carcharodon megalodon) -- was probably big enough to eat a whale.
A photo of the cliffs at Mistaken Point, in Newfoundland
Ediacaran Fossils: One Species at a Time
Oct 27 2011 - 3:37pm
When the cod fishery collapsed in Newfoundland in the early 1990s, the hopes of the local fish harvesters collapsed with it. Hundreds of Newfoundlanders moved away and businesses that depended on the cod fishery closed. But retired schoolteacher Kit Ward of Portugal Cove South wasn’t content to...