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Mathematics in Biology??!!. Mark Pernarowski Montana State University, Bozeman. What Kind of Biology?. Population of organisms - i.e., animals Spread of Disease - i.e., Flu, vaccines, How muscles work - even the heart Diabetes - insulin and glucose
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Mathematics in Biology??!! Mark Pernarowski Montana State University, Bozeman
What Kind of Biology? • Population of organisms - i.e., animals • Spread of Disease - i.e., Flu, vaccines, • How muscles work - even the heart • Diabetes - insulin and glucose • Patterns in natures - zebra stripes, leopard spots • Brain electrical behavior - sight, sound • Organism growth - embryos • Genetics …..and much more
Population Problems • Predator-Prey • X=hare population • Y=lynx population
Spread of Disease • Hong Kong Flu (1968-69 NYC). • Pre-vacinne flu related pneumonia
SIR Model • Susceptibles S • Infected I • Recovered R
How do leeches swim? • Physics of Fluids • F(x,t)=leech force • u=fluid velocity • p=pressure
Patterns in Nature • Chemicals that react and diffuse in animal coats make visible patterns • c(x,t) concentration at time t location x.
Embryo Development -genes • Young embryos form a body axis early on • Why? How? Chemicals cause cells to move.
Models Reproduce Experiments • n=cell density • u=chemical
Some Biology is “Stimulus/Response” • A stimulus I causes an output u • Sometimes get an output even if there is no stimulus (I=0)(i.e., people who talk to you even when you don’t talk to them)
Visual System • The electrical firing rate of your visual system neurons changes with stimulus angle!
Each neuron can be modeled. • Ions move across membrane • Voltage V changes in time
Models of Visual System Orientation Patterns • Activity a(r,t) at time t, position r in your brain.
On - neurons fire immediately • Off- neurons fire after light turned off • Math models explain both and more.
Diabetes • An increase in glucose (sugar) causes pancreas cells to make insulin. Calcium plays a key role.
Bursting Electrical Activity • Calcium makes cells voltage “burst” • Same kind of math models as neurons.
World’s smallest engine! • Molecules which make “ATP” (your energy)
A simpler math model of animal populations • is population at year n=1,2,3,…. • Less animals next year if population is too high. Why?
Maybe population levels out http://www.math.montana.edu/frankw/ccp/modeling/discrete/logistic/appwindow.htm
Conclusion • There will be more math in biology and medicine in your lifetime. • Unlike other science the math models are being discovered right now!