Ancient Seas

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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...
Apr 12, 2013 - 11:29AM
How long have jellyfish lived in the ocean? This jellyfish fossil is from...
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...
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...
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...
Apr 12 2013 - 11:29am
How long have jellyfish lived in the ocean? This jellyfish fossil is from the Cambrian period, more than 500 million years ago. It was found buried in Utah—an area that used to be underwater, covered by the ocean. Fossil jellyfish are rare because they have no bones or other hard parts to turn into...
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...
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.
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.
Jan 26 2012 - 11:53am
Sirenians, or seacows, are a group of marine mammals that include manatees and dugongs. Currently, only a single species of seacow is found anywhere in the world. However, the fossil record of seacows, which dates back 50 million years, tells a different story.
Feb 3 2012 - 11:16am
Dugongs, along with manatees, make up a group of marine mammals called sirenians or seacows. In the modern world, only one species of seacow is found in any one place in the world. However, the fossil record of seacows, which dates back 50 million years, tells a different story.
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...
Jan 26 2010 - 11:45am
Like the modern nautilus, this relative of modern squid hunted from inside the safe haven of a protective shell. Ammonites went extinct around the same time as the dinosaurs—65 million years ago.  Find more about ocean predators in our interactive timeline Who's on Top?
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...
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.
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.
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.
May 11 2012 - 9:58am
Editor's note: Read Nick's first blog post about "toothed" baleen whales to see what their team is excavating on Vancouver Island.