(FISH DISCOVERY) A new study suggests that fish are an important link in the evolution of land animals. The research focuses on how fish can control their movements both in water and on land, and how their jumping skills might have made them the first terrestrial dwellers. Read on for evidence of why we might have evolved from these acrobatic fish. — Global Animal
The surprisingly precise movements of fish. Photo credit: Discoverynews.com

Discovery News, Jennifer Viegas

Any fisherman or flying fish fan knows that fish can execute impressive jumps, but new research demonstrates these leaps can happen with height and precision on land too.

Considering that fish don’t have legs, wings, arms or other helpful anatomy to control such jumps, the feat seems almost improbable.

Alice Gibb, professor of biological sciences at Northern Arizona University, and her team proved it can happen after studying several different types of fish jumping with apparent skill and purpose. The research, published in the Journal of Experimental Zoology: Ecological Genetics and Physiology, was inspired by a mangrove rivulus jumping out of a small net and back into the water. The move wasn’t just a random flop, Gibb noticed. The fish seemed to be in full control.

This control wasn’t lost on land either, which has significant implications for evolutionary biology, Gibb said, because the finding implies that “the invasion of the land by vertebrates may have occurred much more frequently than has been previously thought.” 

In other words, land life on Earth probably started with leaps and bounds, with terrestrial jumping by fully aquatic fish.

Gibb said the study “supports a big-picture theory in evolution,” which is that the nervous system, in its control of bones and muscles, can allow a new behavior to appear without necessarily bringing about a physical change.

In the case of aquatic fish, Gibb said, “This shows that you don’t have to have legs or rigid pectoral fins to move around on land. So if you go back and look at the fossil record to try to say which fish could move around on land, you’d have a hard time knowing for sure.”

The scientists’ tests on everything from guppies to mosquitofish demonstrated that even clearly non-amphibious fish could jump with skill and direction on land.

The mosquitofish “has become our lab rat,” Gibb said. “It’s accessible, it comes from a group that has other jumpers, and it’s been reported that this fish jumps out of the water to get away from predators and then jumps back in.”

The researchers determined that many species produce a coordinated maneuver in which the fish curls its head toward its tail and then pushes off the ground to propel itself through the air.

Jumping ability can even trump swimming.

“Maybe fishes that are very good at jumping are poor swimmers,” Gibb explained. “We want to look at the compromises that may have been made to favor one behavior over another.”

More Discovery News: http://news.discovery.com/animals/fish-jumping-skills-111007.html#mkcpgn=rssnws1

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