Learning Tools for Mathematical Modeling

By Martin H. Weissman

Welcome! The following are tools for students learning mathematical modeling in the life sciences.

Simulations

Simulations of phenomena in the natural world. Specific to particular examples.

Caffeine Simulator

Track the caffeine in your body, with three adjustable doses each day.

Shark and Tuna Interaction-Counter

Relate number of interactions to populations of sharks and tuna.

Shark and Tuna Trajectories

Trajectories in state space and time-series. Interventions.

Insulin Glucose Response

Set parameters for insulin sensitivity, beta cell mass, etc. Look at steady state or a glucose challenge test. Uses a minimal model.

Gentamicin pharmacokinetics

Adjust protocols to explore effect on drug in bloodstream. Exhibits 1st order kinetics.

Higgins-Sel'kov glycolysis model

Adjust parameters to see limit cycle and Hopf bifurcation. Identify source of oscillations in F6P and ADP.

Holling-Tanner predator-prey model

Adjust parameters to see limit cycle and Hopf bifurcation. Sharks with limited appetite.

FitzHugh-Nagumo model

Generalization of van der Pol oscillator. Simplification of Hodgkin-Huxley model for neural spikes.

Hutchinson population growth model

Logistic growth where crowding effect has a time delay. Exhibits Hopf bifurcation and oscillations

Simple muscle simulator

Muscle length with equilibrium point and time delay. Exhibits oscillations from time delay and steep feedback

Tree ring simulator

Simulates radial tree growth (tree rings) with uniformly random growth each year.

Growth and collapse simulator

Simulates things that often grow linearly but occasionally collapse back down to zero. Runs simulation 500 times, displaying histogram of results.

Yule process simulator

Runs simulation of Yule type birth/death process. Tracks populations with dozens of simulations for comparison of outcomes.

Genetic drift simulator

Runs simulation of genetic drift, essentially a Wright-Fisher model with fixed total population. Change parameters, observe fixation of traits, etc.

Atmospheric molecule simulator

Runs a random walk to model up/down motion of molecules in the atmosphere, with adjustable temperature and gravitational bias.

Brownian motion simulator

Simulation of Brownian motion, with adjustable particle size, viscosity, temperature, to replicate Perrin's experiment.

Diffusion simulator

Simulation of diffusion, with 1000 particles undergoing a random walk. Histogram of x-coordinates resembles the bell curve.

Ion channel simulator

Simulation of current from a single ion channel, imitating patch clamp recording. User can choose transition probabilities between open and closed states.

Explorers

Tools for exploring different kinds of equations.

Self-interaction Simulator

Relate the number of self-interactions to populations of moving organisms in a dish.

Dynamic Vector Field Explorer

Play with your own vector fields in the plane, and watch particles blow in the wind.

Data Plotter with Log-scaling

Enter 10 data points, experiment with log-scaling and line of best fit.

Logistic Growth Explorer

Explore parameter changes, and try to fit logistic model to your data by minimizing the residual sum of squares.

Exploration of Equilibrium in 1-D

Explore 1-dimensional dynamical systems. Visualize phase portrait, equilibria, trajectories, and time series.

Generalized Lotka-Volterra Explorer v2

(New and improved!) Control parameters in a 2-dimensional generalized Lotka-Volterra system. Allows exploration of predator-prey, competition, cooperation, coupled with logistic growth.

Simple Harmonic Oscillator (SHO) Explorer

Control parameters in the simple harmonic oscillator. Allows exploration of trajectory shape and period of oscillation.

Discrete Logistic Explorerr

Set birth rate and initial population, and see what happens. Explore bifurcation and the onset of chaos in this classic example.

Rapid Coin Flipper

Choose fair or biased coin, and flip up to 200 times. Provides statistics and random walk to accompany outcomes.

Two-compartment Markov Chain Explorer

Choose the matrix of transition probabilities, and see the populations change while individuals behave stochastically.

Matrix and vector calculator

Quickly enter a matrix, vector, scalar, and see sums and products. Works in 2, 3, 4 dimensions.

Three compartment matrix modeler

Set the transition probabilities, and run the matrix model. Displays time series plots.

2-Dimensional matrix visualizer

Input a 2x2 transition matrix. Displays eigenvalues/eigenvectors. Start with grid of points, and apply the transition matrix to see the effect.

2-Dimensional matrix smiler

Input a 2x2 transition matrix. See the effect of the matrix on a smiley-face. Animate the transition.

Study Aids

Tools to practice fundamental skills, prepare for tests, etc.

Spreadsheet Practice

Learn how to use spreadsheets! For the complete beginner. Self-contained and leads into modeling change equations.

Fundamental Modeling Practice

Practice with randomly generated situations, figure out change equations, graphs, and more. Click buttons to see correct answers.

Trajectory and Time-series Practice

Practice going back and forth between trajectories in state space and time-series plots. Click buttons to see correct answers.

Logarithm Definition Practice

Practice reframing logarithm questions as exponent questions, and answering them. Click buttons to see correct answers. Natural logarithms and unusual exponents included.

Derivative Practice

Practice drawing derivatives from a graph. Practice symbolic derivatives for key functions (linear, quadratic, cubic, exponential, power-law). Click buttons to see correct answers.

Data Sets

Tuna and Sharks in Trieste

Real fisheries data from the port in Trieste. Kilograms of sharks and tuna caught each year.