This is scientific American's 60 second science. I'm Christopher Intalyata. Got a minute?

March 27, 1964. The world's second most powerful recorded earthquake hits Alaska.

In Anchorage, Alaska's largest city.

Buildings collapse. Streets and homes slip into the earth.

Out in the Gulf of Alaska, the ocean bottom seems to sink. Then heaves

upward 50 feet sending a giant wave towards shore.

What happened was the whole Gulf of Alaska and Prince William Sound just sort of tilted and so

near shore, near Alaska that region sank and then out at sea the sea floor raised up.

Susie Basum, a molecular biologist at the University of Oregon.

And so things that were submarine platforms before suddenly were lifted above sea level and then silk could come in and

build more island. And with more island came new freshwater ponds. Those newly

created bodies of water turned out to be the test bed for a natural evolutionary

experiment on a finger-sized fish called the three-spine stickleback. Saltwater fish

went in, freshwater fish came out. Big,very well-armored fish entered freshwater ponds and during the last 50 years they changed their size, their coloration, they changed the size of their eyes, the

length of their spines, many aspects of their skeletons, feeding structures, swimming structures, and became more

stereotypical freshwater fish. But how? Basm and her colleagues ran statistical analyses on the genomes and body measurements of fish

living in those freshwater ponds today.

And they found that saltwater versions of the fish may have actually colonized those freshwater ponds on the study islands at least six times in the last 50 years.

They were able to move in and rapidly adapt because the sea-dwelling fish have a sort of sleeper genome of freshwater traits, just

waiting to be activated.

These are anadramous fish that have been invading freshwater ecosystems over and over and over and those all those freshwater

adaptations have trickled back into the sea allowing the oceanic population which

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