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Ocean Portal by The Smithsonian Institution

Ancient Seas

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IMAGE GALLERY Shark Ancestors 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 w...MORE GALLERIES


	PHOTO MORE PHOTOS Ammonite Like the modern nautilus, this relative of modern squid hunted from inside the s...
	TIMELINE MORE STORIES Top Predators Timeline What makes a top predator? Razor-sharp teeth? Speed? Strength? Size? Who is t...
	BLOG POST MORE STORIES New Archaeocetes from Peru Are the Oldest Fossil Whales from South America The evolution of whales represents one of the great stories in macroevolution. I...

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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...

Fossil Jellyfish

Apr 12, 2013 - 11:29AM

How long have jellyfish lived in the ocean? This jellyfish fossil is from...

Ancient Entoproct Community

Jan 18, 2013 - 10:28AM

For a long time, scientists thought that some small tentacled fossils were...

SPOTLIGHT


Did Whale Evolution Go Backwards? Whales swim, but their ancestors walked. Whales are mammals (like us) whose ancestors lived on land. Life probably began in...

Eocene Whales and Penguins Off the Coast of Peru Sep 12 2011 - 11:43am Offshore Peru, during the Eocene (~56-34 million years ago), showing three archaeocetes (ancient whales), along with a previously described fossil penguin.	Recliner Rudists Aug 9 2012 - 10:27am Where ocean currents were strong, ancient rudist “recliners” lay unattached on the seabed. Notice the pink tentacles, which were used to filter feed. Learn more about ocean life throughout deep time in our Ocean Over Time interactive or an image gallery.
Excavating a "toothed" baleen whale from Vancouver Island May 7 2012 - 3:34pm The whales that we see in today's world can broadly be split into two groups: those with teeth (odontocetes), and those that have baleen (mysticetes) instead of teeth. These two groups share a common ancestor in the Eocene, which had teeth (They looked a lot like the ancient whale skeletons in the...	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.
Rudist Clams Jan 26 2010 - 11:45am Rudist clams are mollusks that went extinct about 65 million years ago. They were the reef builders of the Cretaceous Period, the heyday of the dinosaurs. Today corals have taken over the role rudists once filled.	Ediacaran Community, Proterozoic Eon (2,500 - 542 Million Years Ago) Sep 20 2011 - 3:42pm Earth’s first animals had soft bodies. This illustration shows a community of soft-bodied Ediacaran (edi-A-karan) animals. Some species resemble living ocean creatures. Others are unlike any known organisms and cannot be classified. Scientists have found fossils of these fauna in sedimentary rocks...
Cambrian Period (542 – 488 Million Years Ago) Sep 20 2011 - 4:20pm The basic body plans of all modern animals were set during the Cambrian Period, 542 - 488 million years ago. Your friends, family, and pet turtle may not look much like the creatures here. But we and our fellow animals are heirs of these ancient ocean dwellers. Changes in Earth’s climate and ocean...	Long Before Coral, Mollusks Built the Ocean's Reefs Dec 4 2009 - 3:27pm About 100 million years ago, during the heyday of the dinosaurs, reefs were built by mollusks called rudist clams. Like modern clams, rudists were bivalves, with two shells (or valves) joined at a hinge. But they sure didn’t look like modern clams!
Ancient Entoproct Community Jan 18 2013 - 10:28am For a long time, scientists thought that some small tentacled fossils were early ancestors of jellyfish. But a new study has found that these ancient animals are actually related to an entirely different group of animals: the entoprocts, which are still alive today. The new fossil (Cotyledion...	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.
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.	Did Whale Evolution Go Backwards? Sep 24 2010 - 12:25pm Whales swim, but their ancestors walked. Whales are mammals (like us) whose ancestors lived on land. Life probably began in the ocean and then evolved to colonize the land. Yet the whale’s ancestors gradually moved from land to sea, adapting to their circumstances and surroundings. The ocean...
The Ocean Throughout Geologic Time, An Image Gallery Sep 20 2011 - 3:30pm Evidence shows that life probably began in the ocean at least 3.5 billion years ago. Photosynthesis began more than 2.5 billion years ago—the Great Oxidation Event. But it took hundreds of millions of years for enough oxygen to build up in the atmosphere and ocean to support complex life. The first...	Elevator Rudists May 1 2013 - 9:48am These "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 ocean at our feature Ocean Over Time.
Submersible Collects Deep-Sea Corals Aug 12 2011 - 2:07pm Come along as scientist Dr. Brendan Roark narrates a submersible dive to collect and study deep-sea corals. Roark studies deep-sea corals to understand the history of the ocean and past ocean climates.	Cretaceous-Paleogene Boundary (65 Million Years Ago) Sep 21 2011 - 9:53am This rendering shows life at the end of the Cretaceous Period, before the impact of a 6.2 mi (10 km) asteroid triggered mass extinctions on land and sea. Dinosaurs are the most famous victims of the extinction at the end of the Cretaceous, 65 million years ago. But they weren't alone. Nearly half...