Pasta dry lab using Mark-Recapture

Materials

• uncooked pasta
• markers
• ziploc bag

Procedure

1. A sample population was taken  (figure 1)
2. The sample population was marked (figure 2)
3. The sample population was placed back into the bag and the bag was shaken (figure 3)
4. A handful of pasta was taken out of the bag randomly and the number of previously marked pasta was recorded (figure 4)
5. calculations were performed to estimate size of general population (figure 5) 
6. 2 more trials were performed

Trials

	Trial 1	Trial 2	Trial 3
M	27	27	27
n	27	29	45
m	2	2	3
N	365	392	405

1. After 3 trials of the mark and recapture sampling technique our group came up with 3 estimates. 367, 392 and 405 averaging 387. But when we individually counted the pasta we established with confidence that the true size was 479. Our group was off by 92 pasta and had error rate of 19%.

2. a) Our group only marked 27 pastas which is only 5.6% of the total population. Because only 5.6% were marked it led to our group having estimates way under the actual population size. Also, the pastas we used were previously already marked by similar markers which made it difficult to tell which were marked for this experiment.



    b) Some problems ecologists might encounter are that once the animal is caught, it might become wary of the traps and not get caught again, or maybe other members of the population don't want to associate themselves with the marked individuals because they are different. ecologists may also have to consider the risk of human intervention such factors like hunting, disease or predators may lead to modified population estimates. In the real world ecologists also have to face the very real risk of the population migrating or maybe other animals migrate into the population and disrupt food chains.

3. In order to improve our sampling design and the overall success rate of this experiment, instead of grabbing a handful of pasta we should randomly select each individual pasta. This gives us a more spread out reflection on the population. Also the amount of pasta selected should stay the same giving us a more standardized perspective on the overall population.

Figure 1

Figure 2

figure 5

figure 4

figure 3