Evidence for Evolution

My favorite prediction of Darwin's descent with modification is microevolution- species changing through time. An example that embodies this idea is the migration time in a population of pink salmon. Scientists have discovered this population of salmon have been migrating earlier each year, and they want to find out if a) it is a genetic change and b) if it is due to climate change. They do discover that there has been a phenotypic decrease of the late-migrating fish, which would show microevolution has occurred. They also believe part of the push towards this new migration time does have to do with climate change. In the past, this type of salmon chose when to migrate based on when they could avoid high stream temperatures. With global warming, the high stream temps are coming earlier than they normally have in the past 40 years, which could be an essential factor in this example of microevolution.




Resources: 

    https://royalsocietypublishing.org/doi/10.1098/rspb.2012.1158

Comments

  1. Haley BurnsSeptember 6, 2021 at 6:02 PM

    Do you think higher stream temperatures are the only cause for this? What other factors could potentially cause this?

    ReplyDelete
  2. Evolution: Haley JonesSeptember 9, 2021 at 8:31 AM

    Hi Katie,
    This is an interesting example that seems to be pretty multifaceted. I would be interested to know if the early migration time has something to do with gene flow and a trait being passed, or if it is due to migration at a certain temperature and that temperature occurring earlier than it usually does. Were the researchers able to analyze a genetic connection to the early migration?

    ReplyDelete
  3. Gretchen GrahamSeptember 9, 2021 at 8:52 PM

    Hi Katie!

    I love this example because I had not heard anything about this. I wonder if that decrease in phenotypes would be due to the climate change or due to something that hasn't been found yet.

    ReplyDelete
  4. Emily DavorenSeptember 10, 2021 at 4:44 PM

    This is really interesting to hear about. I have never thought of migration time as a genetic change. I wonder what would specifically be altered genetically to signal these fish to migrate earlier. I realize that climate change could cause them to do this earlier but it is crazy to think of it from this viewpoint. Thanks for sharing some interesting research!

    ReplyDelete
  5. Bridgett WinzerSeptember 10, 2021 at 8:52 PM

    Katie,
    Very well done on this blog post and the evidence accompanying it! I'm glad you mentioned global warming because it continues to prove that there is no perfect species that evolution is striving for because the environment is constantly changing. It's a reminder that evolution is truly about the survival and distribution of alleles. Thanks for your insight!

    ReplyDelete

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