Thursday, June 21, 2012

Ecology: complicated and delicious, just like your ex's facebook status

Ecology was truly love at first sight.  Now I'm not normally one for complicated relationships, but something about ecology has always made my toes tingle. Ecology is the study of the relationship of species and their environment. Like all relationships, this one is dirty, convoluted, and complicated.  Like a good relationship though, I can also be very rewarding and exciting.  Upfront the idea of ecology may seem very simple. You take a species and see how it responds or affects its habitat.  And it's insanely relevant, answers to those questions can help inform conservation, forestry, zoos, climate change, habitat management, zoning, invasion, biological control, and so on.  You also end up incredibly well rounded, using mathematics theory, statistics, experimentation, laboratory control, cross departmental collaboration, biology, physics, chemistry, aquatics, animal behavior, and evolution. Okay, so now you can see how this can get so complicated.

My bio stats professor once said that ecology will always be a strong career because there's never any way to answer everything about even one question. Realistically, the possibilities are endless.  You could have 9 hypotheses to test and none of them be the correct theory.  Moreover, ecology is almost never controlled by one variable. Let's look at the situation that originally got me interested in ecology my junior year in college as a simple starting point.

I still have the original article, I never got rid of it.  It's a 1997 article in Science (one of the top 2 science journals in the world, likely only second to it's London counterpart, Nature).  "Cichlid Fish Diversity Threatened by Eutrophication That Curbs Sexual Selection."  Okay, let's look at this concept bit by bit.

  1. The species: Cichlid fish are found in many places in the world, although warm water.  They are well studied for their species divergence by population.  In other words, often when a population of cichlids becomes isolated in a lake or water way they specialized and diverge.  If they are reintroduced to the population they come from (the source) there will no longer be any breeding between the populations.  
  2. Eutrophication: In aquatics, the water quality and clarity is often generalized into 3 majors groups
    1. Oligotrophic: clear crystal water with little algal blooming or fertilizer
    2. Mesotrophic: moderate clarity with some algal blooms likely giving the water a hue of blue or green for parts of the year
    3. Eutrophic: murky, dark water with little clarity and high algal blooms giving the shoreline a very green color. SO when we say "eutrophication" we mean a lake that is moving (or being pushed) towards poor water clarity and quality.  In this case reducing vision within the water column. 
  3. Sexual selection: Alright so this term should be more familiar since we talked about it in my evolution post.  Specifically here it is important to know that females choose their male mates based on color and color brightness.  So there is selection pressure on the males to be a certain color and to be a very bright variant of that color.  Think about how this would be different if there were a predator? 
  4. So the kicker with this research is that over time, as the lake becomes more euthrophic and more murky, the females have less ability to visually choose their males and often do so indiscriminately.  They breed across the lines of sub species as well, no longer able to choose by color.  As a result, there is no benefit for the male to invest a lot of energy in being colorful so there is a reversal (another term you know!) to being dull fish.  The males and females were becoming dull grey in color and the populations were almost completely intermixed again as a result!!!

Alright, I will continue to talk about ecology next week and how it becomes more complicated.  If you have any questions so far, let me know!


"Science is one thing, wisdom is another. Science is an edged tool, with which men play like children, and cut their own fingers." Sir Arthur Eddington

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