“One of the great migration stories of the world” – Shrimp in the mighty Mississippi.

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Macrobrachium ohione, by Clinton and Charles Robertson, via Flickr.

The Mississippi River that we know today is a creation of the army corps of engineers. Before they got to levying, dredging and damming it into submission, it was a wild and meandering thing that harbored great concentrations of wildlife. One component of that was a massively abundant shrimp with an amazing life cycle:

It turned out that in pre-colonial times the shrimp traveled all the way north into the upper reaches of the Mississippi’s main eastern tributary, the Ohio River, and back again – a 2,000-mile round trip. It was a journey more amazing than similarly epic migrators like salmon. For whereas adult salmon may have an equally long journey to their upstream spawning sites, it is the quarter-inch juvenile shrimp that swim and crawl 1,000 miles upstream against the strong currents of the Mississippi.

What happened to these shrimp? Go read the story to find out.

NBA and WNBA players perform differently with age

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Life-history traits are often shaped by a balance between somatic maintenance and reproductive investment. That is, an individual wants their own cells to be active, but also needs to invest in making offspring. This tension between natural and sexual selection can generate age-related physiological trajectories that differ between organisms, environments and populations. In simpler terms, how you age is as much an evolutionary response to your environment as it is to your reproductive success!

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