MORE GEOLOGIC TIME
May 2 2013 - 10:48am
Editor's note: This is an excerpt from Daniel Botkin's new book The Moon in the Nautilus Shell: Discordant Harmonies Reconsidered . He will be in Washington, D.C. on Wednesday, May 8th for a lecture...
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...
Mar 25 2010 - 4:50pm
Lenticulina secans -- this foram lives on the seafloor. This specimen was collected from ocean sediments in southeast Tanzania. It comes from a time over 92 million years ago when both the polar...
Sep 20 2011 - 3:27pm
Humans are late arrivals on Earth. For nearly 75% of Earth’s history, life consisted of single-celled microbes without a nucleus (prokaryotes). Volcanoes and erosion sculpted Earth 3.5 billion years...
Dec 4 2009 - 2:27pm
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...
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...
Dec 4 2009 - 2:21pm
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—...
Sep 12 2011 - 4:40pm
The evolution of whales represents one of the great stories in macroevolution. It's a narrative that has mostly benefitted from an extraordinary series of fossils recovered from rocks around the...
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. Top to bottom: Perudyptes devriesi ,...
Jan 26 2010 - 10:45am
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...
Jun 7 2011 - 11:30am
This specimen of the deep-sea coral Desmophyllum dianthus shows the visible bands that help marine scientists learn how ocean conditions changed over time. By looking at the thickness of each band,...
Sep 12 2011 - 2:55pm
These are fossil remains of archaeocetes, ancient whales, from the Paracas Formation of Peru's Pisco Basin . Smithsonian paleobiologist Nicholas D. Pyenson and a team of scientists discovered 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...
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...
Jan 26 2012 - 10:53am
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...
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...
Sep 20 2011 - 4:36pm
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...
Dec 4 2009 - 2:25pm
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 . Discover more about the...
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