Smithsonian.com

Some scientists say that we are living in a new epoch of geological time—one they call the Anthropocene—that is marked by what may be the sixth mass extinction in the history of our planet. A scary number of creatures have gone extinct in recent human memory, some of them even in my lifetime. No one today argues that extinction is impossible, like they do with evolution, but it wasn’t always that way.

Extinction is a fairly new concept in human thought. Shelley Emling explains in The Fossil Hunter:

For centuries, Christians were convinced that Genesis told the true story of creation. Fossils only reinforced the biblical account. For example, some fossils were found at such high altitudes that people thought they must surely have been deposited there as a result of the worldwide flood depicted in Genesis….After all, the Bible stated that God created the heavens and the earth and every living thing in it in just six days. There was never any mention of a prehistory and therefore never any mention of prehistoric animals….In general, very few people doubted the Bible’s veracity.

Mastodons and other fossilized creatures challenged the idea that God's Earth was unchanging (via wikimedia commons)

Today people argue against evolution by citing the Bible, and 300 years ago they argued against extinction citing that same source. The world, they said, was exactly as God had made it 6,000 years before and it hadn’t changed since then.

But the fossils kept coming. In England, Mary Anning and others were digging up ichthyosaurs and pleisiosaurs and other fossils that didn’t look like anything living. In Siberia, Russians were finding woolly mammoths. And in the United States, Americans were digging up mammoths and mastodons. Richard Conniff writes in the April issue of Smithsonian:

The discovery of such monstrous creatures raised troubling questions. [French naturalist Georges] Cuvier made the case that both mammoths and mastodons had vanished from the face of the earth; their bones were just too different from any known pachyderm. It was the first time the scientific world accepted the idea that any species had gone extinct—a challenge to the doctrine that species were a permanent, unchanging heritage from the Garden of Eden. The disappearance of such creatures also cast doubt on the idea that the earth was just 6,000 years old, as the Bible seemed to teach.

In fact, mammoths and mastodons shook the foundations of conventional thought. In place of the orderly old world, where each species had its proper place in a great chain of being, Cuvier was soon depicting a chaotic past in which flood, ice and earthquake swept away “living organisms without number,” leaving behind only scattered bones and dust.

Eventually the evidence was overwhelming—there were thousands upon thousands of creatures that no longer existed. Extinction was reality and no one argues otherwise anymore. In fact, we now know that the rate of extinction has changed over time and reached five peaks called mass extinctions (the most familiar will be the Cretaceous-Tertiary extinction event, 65 million years ago, which wiped out the dinosaurs). We may be on our way to a sixth.

But how can people have come to understand that extinction is real—and thus God’s world must have changed and is doing so before our very eyes—but still think that evolution is bunk? I don’t have an easy answer to this (and if any creationists stumble upon this, please explain your views in the comments below), but it might have something to do with the nature of the evidence. It is easier to believe that creatures have ceased to exist, especially when you can see that happening right now, than it is to visualize the path from, say, Ardi to humans. Evolution is a slow process that takes place over long periods of time, and the bits we can see—like the changes in flu viruses from year to year or a single bird species slowly diverging into two—can be easy for some to dismiss. That extinction became an accepted concept gives me hope, however, that more people may one day accept evolution as well.

Angkor Wat (courtesy of flickr user tylerdurden1)

From the 9th to the 13th centuries, Angkor was the center of the Khmer Empire and the largest city in the world. Roads and canals connected the sprawling complex, which included hundreds of temples. But it didn’t last.

Today, two million people each year visit the site in Cambodia, though much of it is in ruins. Archaeologists and historians have been uncertain about the reason for Angkor’s decline, but they have speculated that war with the Thais may have contributed to the city’s downfall or that the Khmer may have moved their capital to Phnom Penh to make it easier to trade with the Chinese. However, an international group of scientists is now arguing that climate change may, too, have played a role. Their study will be published this week in PNAS.

During its dominance, Angkor covered an area of nearly 400 square miles. To maintain such a large society, the city had a vast infrastructure that was dependent on the annual monsoons to flood the the region’s lowlands and support agriculture. A new analysis of tree ring data from nearby Thailand and Vietnam, though, shows that the area experienced decades-long periods of drought during the 14th and 15th centuries, interspersed with intense monsoons.

The Khmer would have been unable to quickly adapt their large network of reservoirs and canals during the periods of drought, the researchers say, and agriculture would have suffered. Serious flooding during the monsoons damaged that same infrastructure that the farms depended on. Additional economic and political stresses would have combined with the climate and resulting agricultural problems, the scientists say, and contributed to the city’s collapse.

NASA is usually a master of the art of self promotion, which is why I’m a bit perplexed by this page of downloadable posters promoting NASA manned space missions. The most innocuous ones are simply boring, with proud astronauts grouped in front of a space shuttle or some stars. (No one looks good in an orange space suit, but that’s the uniform.) What I’m talking about, though, are the posters where NASA is trying to be “creative.” Who thought that giving everyone bright blue hair was a good idea? Or referencing Rat Pack promotional posters from the 1960s? Or dressing up the team as characters from The Matrix:

Or Star Trek:

Or Reservoir Dogs (at least it didn’t cost much; all they had to buy for this photo shoot were a few pairs of sunglasses):

Most perplexing to me, though, is this poster for the upcoming May mission to the International Space Station:

Why baseball?

Who wants these posters? I can’t see little kids who dream of being astronauts wanting to hang these up on their bedroom walls. And if I was in one of these missions, I would be more than a little embarrassed by some of them. So why is NASA spending time and money on this? Or am I just not getting the joke?

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A composite image of the Earth at night (credit: NASA/Goddard Space Flight Center, Scientific Visualization Studio)

One of the most wonderful memories I have from a sailing trip is being miles and miles from shore on a moonless night and seeing the thousands of stars twinkling in the sky. It’s something that most people in the developed world never see; most of the stars are drowned out by light pollution. As you can see in the image above, even at night it’s pretty bright in the parts of the world where most of the people live.

A lot of that light is wasted energy, which equals unnecessary carbon emissions. But what if we turned out the lights, just for an hour? That’s what the World Wildlife Fund is challenging all of us to do Saturday night at 8:30 p.m. local time. They call it Earth Hour. Millions of people, hundreds of cities and a host of organizations—including my very own Smithsonian Institution—will be turning out the lights tomorrow night to say that something needs to be done about climate change. I will, too. Will you?

(Check out the entire collection of Surprising Science’s Pictures of the Week on our Facebook fan page.)

A jellyfish on an Australian beach (courtesy of flickr user Squirmelia)

Marine biologists need your help. The next time you go to the beach, keep a lookout for the creatures that have washed up onto the sand. And if you find a jellyfish, squid or other kind of unusual marine life, including a red tide bloom, please, please report your sighting to Jellywatch.

Jellywatch is the creation of the aptly-named marine biologist Steve Haddock, from the Monterey Bay Aquarium Research Institute. The web site harnesses social networking to create a database of sightings of marine life so scientists can track what is happening in our oceans around the world.

Visitors to Jellywatch can upload information about their sightings, including images, and keep track of what they’ve previously found. They can also compare their sightings with those of other beachcombers from around the world. Already the database has information about a recent red tide off Cornwall, England; pygmy killer whales seen near Hawaii and Humboldt squid near Vancouver Island.

What strange things will you find this summer?

(Hat tip: Helen Fields)