Rapid Evolution Saved This Fish From Pollution

The Atlantic killfish is a very common, minnow-like fish that lives in the rivers that boarder New Jersey and Pennsylvania. The fact that they lived there was very interesting to researchers because these waters are very toxic due to the toxic materials that run into them from surrounding factories. Chemicals like DDT and Agent Orange completely invade these waters, and in large volumes.  They believe that it is an "evolutionary miracle" that they can survive these conditions because most organisms can not. Researchers did studies and found that these fish just have certain genetic adaptations no matter where they live; even if they do live in less polluted waters.


http://www.natureworldnews.com/articles/33874/20161212/killifish-mutant-fish-evolved-survive-toxic-polluted-waters.htm

Atlantic Killifish Adaptation

Species change according to the surrounding environment for survival. This adaptation can take a couple of years or even millions demanding on the species. Most species become extincted before they are able to catch up to the environmental chances going on around them. For a species to go through evolution in a short period of times, that is able to adapt to the changing environment as it is happening around them means that the species could have a high rate of genetic diversity  Most species though do not have such high genetic diversity. 

A recent study was done on 400 Atlantic Killifish from a polluted/nonpolluted area. The study showed that they are "8,000 times more resistant" to pollution than any other fish studied (ScienceDaily). Scientist thought it could be genetic diversity but then discovered that the Atlantic Killifish already had a genetic variation for pollution, that allows them to adapt to such high polluted areas so quickly. While the other species are dying from the pollution or undergoing mutations (extra fin, 2 heads), the Atlantic Killifish comes out unharmed from all the pollution. There are not that many solutions to withstand pollution and this may be one of the limited adaptation to it. 

https://www.sciencedaily.com/releases/2016/12/161208143334.htm

The Atlantic Killifish

The Atlantic killifish is a small minnow sized fish that lives in the area of the Lower Passaic River and the Newark Bay.  This fish has been subject to a lot of chemicals entering it's habitat and polluting it's ecosystem.  Naturally, large populations of fish and other marine life have died off, but the killifish has been thriving.  Researchers have found that this is due to an extremely quick paced evolution.  Due to the fact that the killifish had such a large population, and had been subject to these chemicals since the production of Agent Orange started, some fish had developed helpful mutations to resist the toxins in the water.  These fish survived and thrived in the toxic water, while now mutated fish died off.  These survivors reproduced, passing down the mutations, and creating a brand new Atlantic killifish.  This new killifish is back to it's large population size, and is still thriving and growing in the polluted water.

I think that the killifish is an amazing example of evolution right in front of our eyes.  It evolved to form a completely new pollutant tolerant species of Atlantic killifish in the span of only a couple decades.  Normally evolution can take hundreds or thousands of years, but this little tiny fish managed to do it so fast.  This is most likely just due to it's extremely large population, and it's very short generation time.  These help traits get passed down very quickly and efficiently throughout the generations.

http://www.nytimes.com/2016/12/09/science/atlantic-killfish-evolution-pollution.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science&region=rank&module=package&version=highlights&contentPlacement=5&pgtype=sectionfront&_r=0 

http://science.sciencemag.org/content/354/6317/1305

Against the tide: A fish adapts quickly to lethal levels of pollution

The Atlantic Killfish has adapted to live in water with a high amount of pollution that would normally kill them.  The killfish is up to 8,000 times more resistant to pollution than other fish.  This fish exhibits an extremely high level of genetic variation, that is higher than any other vertebrate.  Insects and bacteria have a high level of genetic variation which enables them to adapt quickly to resist pesticides and drugs used against them.  Scientists studied the complete genome of 400 killfish that they took from polluted and nonpolluted sites.  They chose sites that had been polluted with dioxins, heavy metals, hydrocarbons and other chemicals.  The fish were taken from New Bedford Harbor, Newark Bay, Connecticut's Bridgeport area, and Virginia's Elizabeth River.  These sites have been polluted since the 1950's and 1960's.  They found that some populations of Atlantic Killfish evolved tolerance through a molecular pathway once exposed to toxic pollution.  This study may lead to understanding genes conferring tolerance of specific chemicals.

https://www.sciencedaily.com/releases/2016/12/161208143334.htm
http://science.sciencemag.org/content/354/6317/1305.full