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Lecture 23

BIOL 1070 Lecture Notes - Lecture 23: Nuclear Dna, Mitochondrion

Course Code
BIOL 1070
Shoshanah Jacobs

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BIOL1070 Class 23 4 April 2016
Polar Bear-Grizzly Bear Hybridization
Iclicker: B
Polar Bear-Grizzly Hybrid
Hybrid offspring that is able to produce more offspring
People accidentally shot and killed the hybrid, scientists were able to then collect DNA,
blood, etc. and analyze it
Usually we use nuclear DNA to classify organisms
o Nuclear DNA is passed on through lineage
o Where does nuclear DNA come from?
Sperm & eggs
Mitochondria from mother
o Polar bears are monophyletic based on nuclear DNA
Female polar bears and male grizzly bears
What could happen to polar bears in a warmer climate?
What does their fate depend on? In what way does it depend on these factors?
o Climate change and human intervention because as long as you have this
problem, there are going to be other species moving and changing their
o Percentage of time there is ice left to hunt on, food sources and availability
o Is there variation in the population of polar bears
Questions and Implications
Polar bears have a comparatively weak jaw, they just chew on fat, not the meat of seals
Grizzly bears eat a variety of things so it is grinding all sorts of vegetation, meaning it
needs a very strong skull
Polar bears swim really well, grizzly bears are not great swimmers
Polar bears biologically can have up to 3 cubs, and statistically lately they have mostly
just been having 1 cub
Declining body condition of polar bears graph (will likely be on exam)
Is there available habitat (abiotic)? Competition (biotic)?
Range, what are the implications for their range?
o Land mass, resources, etc.
Very tied to land and not much going on in the middle, problems with moving north
because they have only water to go to
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