The Passaic River and Newark Bay in New
Jersey are full of toxic pollutants, killing many fish and organisms in the
area. However, one of the most diverse vertebrates, the Atlantic killifish, has
managed to adapt to these conditions. Several independent populations of killifish have evolved different adaptations to the toxic environment.
Biologist Diane Nacci with the Environmental Protection Agency (EPA) and other
scientists compared 384 killifish genomes, finding that tolerance to this
pollution is found on the aryl hydrocarbon receptor (AHR) signaling pathway for
each of the populations, but that different nucleotide patterns were found in
each one. An environment that would kill killifish without the mutation can
house several different populations with slightly different mutations. Scientists
believe that the ability for killifish to adapt quickly are due to very large
populations, and therefore greater nucleotide diversity.
However, though some animal species have
the capacity to adapt to large amounts of pollution and effects from climate
change, that does not mean that all species are capable of that. It is likely
that only a select few species will have the capacity to mutate or evolve
resistance to human-induced effects such as pollution or accelerated climate
change. On a different note, if the water is cleared up again, the killifish
with the mutation for pollution resistance may not survive as well as killifish
without the mutation, though by that point most if not all of the killifish
without the pollution resistance in the area may have already gone extinct. It is
very important to look at the grand scheme of things, and if people continue to
contribute pollution and fossil fuels into the environment, species that are
low in numbers are unlikely to develop a resistance and are likely to go
extinct. Though this study gives clues into how natural selection operates
under extreme conditions, people should not let the planet and its living
creatures come to this point.
At the rate our water is being polluted, it's not a bad thing that these fish are building a resistance to it. I would have never thought that any marine creatures could adapt to living in a polluted environment. I would like to see in the future other marine animals with the mutation to live in polluted waters because maybe then less marine animals will be at risk for extinction.
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