After all, water speed is known to be an important selective agent for fish that influences body shape over time. Kern and Langerhans hypothesized that increased stream water velocity would lead to changes in fish body shape that improve swimming efficiency. "We wanted to test rapid body shape evolution in western and central North Carolina stream fish in response to urbanization," says Langerhans. They also headed to the museum to examine historical specimens spanning 50 years to determine how the body shape of these fish species have changed over time. This species became more streamlined in urbanized areas, which would enable it to adapt to variable and high velocity water flow.

Source: Forbes April 30, 2018 01:18 UTC