Biogeography: From Penguin Rovers to Declining Polar Bears

1.            Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms generally vary along geographic gradients of latitude, elevation, isolation and habitat. Incorporating the theory of plate tectonics and fossil evidence helps explain both similar and dissimilar flora and fauna.

1.             Biogeography helps explain why penguins are found in the Antarctic and polar bears are found in the Arctic. But what explains this emperor penguin decoy rover?!

       

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       This National Geographic article about sending in penguin rovers describes the lower stress the penguins exhibit at having a cute penguin rover rather than a human collect data.

         Emperor penguins are quite shy so studying them by sending in humans tends to raise anxiety levels and heart rates when researchers step in to study the penguins and climate change. 

         Back to biogeography: the location of penguins in the southern hemisphere is correlated with those areas being connected through geologic time:

         Likewise, polar bears' habitats in the northern hemisphere are correlated with areas which were once or are currently connected tectonically. 

     The location of the continents as one super landmass known as Pangaea up until about 200 my ago is illustrated here:

        Then, about 200 million years ago, Laurasia drifted northward from Gondwanaland (surely you've seen "Reunite Gondwanaland!" tee-shirts):

     
           Polar bears' decline by almost 50 percent in research presented this week doesn't include rolling or swimming polar bear rovers. It does show alarming drops in the polar bear population due to thinning sea ice and concomitant inability to hunt for seals, a key part of their diet.
   

      This article from Brown University ties together clade and cladograms and Biogeography. 


      Still scratching my head about alligator distribution in the southeastern U.S. and easternmost China (as discussed briefly last week). The time frame of alligator distribution only from Pleistocene to Recent likely explains part of it. But part is still a mystery.

         Red rover, red rover, let the alligators come over and explain their distribution.
Biogeographically,
Steph

           P.S. My friend, Cat, so adores penguins her personal email address includes gentoo. She and I were in the same plate tectonics class senior year at Smith so we go back tectonically as well as penguinally. Cat, this one is for you! 
           The transformation gets me every time. . .