In an incredible research study, scientists studied juvenile bichir (a type of fish) on land to understand the evolutionary changes that may have taken place about 400 million years ago. That’s right- teaching fish how to walk is teaching researchers about evolution! These African fish are unique because they have lungs AND gills, and juveniles will sometimes walk on their fins. Researchers believe that bichirs walk in a way that is similar to early tetrapod ancestors.
When scientists looked at the differences in walking ability between bichirs raised in an aquatic environment versus bichirs raised in a terrestrial environnment, they found that the terrestrial animals became much more efficient at walking. What’s more, their anatomy began to change to facilitate walking!
This research suggests that organisms’ anatomy is changed in response to environmental changes. This is called developmental plasticity. The theory is that developmental plasticity gave early ancestors of tetrapods the ability to walk onto land. Once in a terrestrial environment, the animals were forced to evolve more quickly to keep up with the environment.
This research is amazing, because scientists pretty much created a snapshot of evolution right in the laboratory! They also provided a pretty good basis for the argument that plasticity was important in the evolutionary steps that led to walking. Read more about it here: http://www.nature.com/news/how-fish-can-learn-to-walk-1.15778
Electric eels are fascinating animals, not only because they look pretty cool, but also because they can generate electricity and deliver shocks of up to 600 volts. But they’re not the only fish that can produce electric fields, and recently, research at the University of Wisconsin, Madison has yielded some surprising information about the evolution of this ability- and what it could mean for other species.
Researchers analyzed the genes of the electric eel as well as other electric fish from unrelated families. It appears that there are a limited number of ways to evolve electric organs, and in at least six different fish, their electric organs evolved in the same way.
So… why should we care? By understanding the way electric organs were created through evolution, scientists may be able to gain the information needed to one day create electric organs in humans or other other animals. The zebrafish, a commonly used research animal, may play a role in attempts at this type of modification. If humans were able to have electric organs, they could possibly serve to power pacemakers, neurostimulators, or other implanted medical devices. Read more about it here:
Turns out that some fish have a secret code- of colors! We now know that over 180 species of fish exhibit biofluorescence: they absorb blue light, transform it, and emit a different colored light. In fact, fluorescent proteins that were originally derived from jellyfish are now commonly used in biomedical research applications. Researchers can track these fluorescent proteins to determine gene expression, which is pretty cool.
But while scientists have known about biofluorescence in jellyfish and corals for years, it’s only recently that biofluorescence in eels, fish, and sharks has been observed. It hasn’t been detected before, because like a true secret code, not everyone can ‘read’ it. Many fish have yellow filters in their eyes, allowing them to see this secret code- but the colors are undetectable to the human eye. The discovery was made by accident- underwater photography using blue lights revealed an eel that glowed green when the pictures were developed!
So what’s the purpose of this secret code? Well, they’re not quite sure yet. But it will be interesting to see what scientists can learn about these fish, both for a better understanding of the animals as well as a determination of possible research applications. Another reason why science kicks ass- unlocking secret codes is all in a day’s work!