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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...
How long have jellyfish lived in the ocean? This jellyfish fossil is from the...
Monodontids, the group of whales that includes the belugas and narwhals...
The whales that we see in today's world can broadly be split into two groups:...

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Today, filter feeders like clams, sponges, krill, baleen whales, fishes, and many others fill the ocean, spending their days filtering and eating tiny particles from the water. But when did the first filter feeder evolve? The...
For a long time, scientists thought that some small tentacled fossils were...
This early whale was well suited to life at sea. But it also lived on land...

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When you're standing in a museum surrounded by fossils, you can almost imagine drifting through time to when long-extinct...

The Ocean Blog

Not all fossils from the Cambrian period became amulets; instead the extinct Hallucigenia sparsa was notable for its spines.
Crinoids (echinoderms related to sea stars and sea urchins) dominate the Paleozoic shallow water habitat in this illustration. They evolved a variety of stalk heights, which enabled them to capture...
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...
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...
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...
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...
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...
Globotruncana falsostuarti -- a foram that lived about 75 million years ago, during the Cretaceous Period, from southeastern Tanzania. By measuring the chemistry in the shell, scientists can estimate...
Most people have never heard of the Hawaiian petrel , an endangered, crow-sized seabird that spends the majority of its life searching for food over the North Pacific Ocean. Nevertheless, this bird...
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.
This illustration shows the edge of a warm inland sea during the Cretaceous Period, heyday of the dinosaurs. Constantly shifting sediment supported new groups of organisms, including rudist clams—...
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,...
An archaeologist arranges a deep-sea core from off the coast of Britain. These cores are long cylinders of the earth's crust, drilled up from beneath the seafloor. When the cores shown here are...
The Haplophrentis carinatus had two oar-like appendages (called “helens”) used to stabilize the creature and help it move along the ocean bottom.
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...
Hantkenina mexicana -- a foram with elongated shell chambers that lived between 45-49 million years ago, during the Eocene Epoch. This specimen is from marine sediments that were drilled in the...
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.
The Wiwaxia corrugata may have molted its scales in order to grow past these hard boundaries.
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