Microcosm biology download#

Take some time to familiarize yourself with the model before beginning the exercise. The volume and light level of the microcosm can be adjusted in the simulation. When ‘Go’ is clicked on the individuals reproduce, feed or die. You can add a specified amount of each microbe, and watch them move about the dish.

Microcosm Model is used to simulate the population growth in Escherichia coli (bacteria), Paramecium aurelia (protists), Paramecium bursaria (protists) and Didinium nasutum (protists) Procedure: The model opens to a virtual petri dish, which is initially filled with sterile nutrient broth.INVESTIGATION: POPULATION DYNAMICS Materials Needed: Remember, the goal of this exercise is to understand how different species interact within a microcosm and how these interactions affect their population dynamics. If a population shows logistic growth, it means the population is growing rapidly but then slows down as it approaches its carrying capacity. For example, if a population shows exponential growth, it means the population is growing at a rate proportional to its current size. Use these results to estimate the growth rates for each population. Qualitative results: These are non-numerical data, such as the type of population growth (exponential or logistic) and any observable patterns or trends. Quantitative results: These are numerical data, such as the population size at different time points and the average population growth. To interpret and explain the different growth rates for each of the populations, you will need to analyze both quantitative and qualitative results. Repeat for bacteria and the two protist populations: Repeat step 3 for the bacteria and the two protist populations you chose. Repeat for the bacteria and second protist population: Repeat step 3 for the bacteria and the second protist population you chose. Record your observations and calculate the average population growth as before. Add the bacteria and the first two protist populations into the petri dish, keeping all other variables the same, including initial population numbers. Reset the simulation and choose two protist populations: Reset the simulation and choose two of the three protist populations for further study. Repeat for each protist species: Repeat the same procedure for each protist species (Paramecium aurelia, Paramecium bursaria, and Didinium nasutum), each with an initial population of 20. To calculate the average population growth, add up the total population size at each time point and divide by the number of time points.Īverage Population Growth = Total Population Size / Number of Time Points Note down the time it takes for the population to grow, the change in population size, and the type of population growth. Add 200 bacteria into the petri dish: After adding the bacteria, click 'Go' to start the simulation.Interpretation & Analysis: Use quantitative and qualitative results to interpret and explain the different growth rates for each of the populations answer the following question using estimation Repeat step 3 for bacteria together with the two protist populations you chose. Repeat step 3 for the bacteria and second protist population you chose. Record observations about the time the population grows, the change in population size, and type of population growth. Keep all other variables the same, including initial population numbers. Add the bacteria with the first two of the populations you chose into the petri dish. Choose two of the three protist populations to study further. Repeat three more times, once for each protist species and each with an initial population of 20. Select ‘Go’ to observe the population grow over time. Add the default amount of 200 bacteria into the petri dish.

Microcosm biology download#

You can download your graph using the buttons in the top right corner above the graph. Clicking on ‘Go’ a second time stops the simulation, and clicking on ‘Setup’ resets the simulation.