Practical: Data loggers & Computer Modelling (OCR AS Biology): Revision Note

Practical: Data loggers & Computer Modelling

Data loggers

• Dataloggers are a tool that allows for the quick and efficient gathering of data

• This technology can be used for simple data collection (e.g. breathing rate) or for more complex data collection (e.g. a number of probes monitoring different variables attached to a main computer)

• The information contained within a datalogger can be inputted into a computer and formatted into a table

• After this is done the computer is able to calculate the mean, perform statistical tests and plot graphs using the data

Uses of computer modelling

• Computer modelling can be used to study the theoretical impact on populations from processes such as:

  • Ecological succession / zonation

  • Infectious disease transmission / epidemiolgy

  • Predator-prey relationships

  • Natural selection

  • Genetic drift

• One of the benefits of these computer programs is that time can be sped up to predict the future outcome of populations and environments

Computer programs and natural selection

• Computer programs can be used to model the effects of natural selection

  • They usually start off with a simple simulated population, with no particular selection pressures acting upon it

• Natural selection can then be investigated by changing various factors and observing the effects on the simulated population

• Examples of factors that can be changed include:

  • The presence or absence of different biotic and abiotic selection pressures (such as predators, disease and food availability)

  • Making new, specifically selected mutations appear in the population

  • Changing the likelihood that a new mutation will appear in the population

  • Switching which alleles are dominant and which are recessive

  • Changing the environment the species is in

  • Changing one or more of the adaptations of the species in the simulated population

• The effects of these changing factors can be modelled by the program and the probabilities of different outcomes for the simulated population can be calculated

• One of the benefits of these computer programs is that time can be sped up

  • This means that natural selection, which for many species would normally occur over very long time periods and many many generations, can be modelled and the effects observed in much shorter and more experimentally appropriate timescales

Computer programs and genetic drift

• When a population is significantly small, chance can affect which alleles get passed onto the next generation

• Over time some alleles can be lost or favoured purely by chance

• When there is a gradual change in allele frequencies in a small population due to chance and not natural selection then genetic drift is occurring

• Computer programs similar to those described above can be used to model genetic drift