Sunday, May 9, 2010
City Lights Affect Species Evolution
The presence of city lights will affect a host of organism's evolution. For millions of years nocturnal species have been adapting to see better, hide better, use the moon and stars as navigational points and now all that is changing. Instead of the dim glow of the moon city and suburb dwelling species are blasted with the brightness of the mid-day's sun throughout the night. How will they change?
It isn't just the insects that will be affect. It is also their predators and migratory animals. It's a common occurrence for me to see toads perched below street lights waiting for a morsel and I can easily see how a evolution could easily select for toads that like the street light's glow (perhaps their eyes will change, perhaps their behavior). I see the same to be true with bats. Any smart bat will quickly realize that under a street light is the place to be for a quick and easy meal. There is one large bridge that I run underneath that this is especially true and based on sightings and chirps I hear I would imagine there to be several hundred bats within the area (modern day 'caves').
What about circadian rhythms? Another relatively frequent occurrence while I run is to hear birds chirping in trees near very brightly lit parking lots. Surely this didn't happen before man. Their brain is confused. Is it day time or night time? How will 24 hour light affect sleep patterns in animals? Why stop there! How will/does it affect us, humans, now!!!?
Questions that might be answered by experimentation: In a new housing development, would insects 'learn' to avoid bright lights at night to avoid getting eaten? How have predators adapted to use this new 'watering hole'? Are insects using lights as a meeting ground to mate? Are circadian rhythms affected by street lights? Are organism's eyes changing to deal with the new exposure (iris constriction) and/or spectrum used? How are birds adapting to being 'blind' to the stars?