That nagging question
My definition of species has been tested over this last year, and it has failed. While writing a polar bear unit study (www.UnitStudiesByGwen.com) I discovered that polar bears can mate with brown bears and produce fertile offspring; however, polar bears are grouped as a separate species.
Polar bears have longer necks than brown bears. Polar bears have smaller ears and tails-a cold weather adaptation. Polar bears have re-developed their carnasial teeth and primarily eat meat. Brown bears have lost their carnasial teeth and are omnivores. Brown bears hibernate over the winter; polar bears never actually hibernate. Brown bears cannot survive in the arctic and polar bears don’t fare well in warmer areas.
The two types of bears definitely have a pile of differences-but, but, but they can mate and have fertile offspring.
So, “What is the modern definition of species” is my nagging question. I have started researching this, but I haven’t yet answered it to my satisfaction. I think I’ll end up with another unit study on Taxonomy before I have the answer.
Labels: definition, polar bear, species, taxonomy, unit studies, unit study
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