Purpose:The purpose of this lab to mimic the mark-recapture technique, that is performed when estimating population.

Background:Sampling is a technique used to estimate population size, where organisms in few small areas are counted and are projected to the entire area. Another way to determine populations is tagging. The purpose is to track migration patterns, health and range. It is also a way to help determine population numbers. After taking random samples and finding the percent tagged, biologists can hypothesize the population in the area.

Procedure:

Background:Sampling is a technique used to estimate population size, where organisms in few small areas are counted and are projected to the entire area. Another way to determine populations is tagging. The purpose is to track migration patterns, health and range. It is also a way to help determine population numbers. After taking random samples and finding the percent tagged, biologists can hypothesize the population in the area.

Procedure:

- Get a bowl with your "species" (in this case, it if "fish" crackers)
- Do NOT count the number of fish yet.
- Have one member remove a handful of fish. Write the number here: 27
- Count the number of fish you remove, and replace it with tagged fish (colored fish).
- Mix the pond to distribute the fish.
- One member at a time, without looking will remove a handful. Record the number of total fish, number of tagged fish and find the percentage of tagged fish.
- Return to the bowl and repeat the process 20 times

1. What is the mean (average) of your percent tagged fish from your 20 samples?

26%

2. Using the following formula, determine an estimated population for your pond: Population Size= [Total # captured*number marked (line#3 above)]/total number captured with mark

40

3. Now actually count the number of fish in your bowl

65

4. Find your percentage error by using the following formula: 100(Estimate population- actual population)/actual population

18% percent error.

5. What concerns should a biologist have about a species' habits before (s)he uses this method to approximate the size of a population?

The species might have migrated to a different area, therefore the biologists are unable get the information they need.

Conclusion: How did you fulfill the purpose? What did you learn?

I learned how to estimate populations with different methods, like sampling, tagging and mark-recapturing.

26%

2. Using the following formula, determine an estimated population for your pond: Population Size= [Total # captured*number marked (line#3 above)]/total number captured with mark

40

3. Now actually count the number of fish in your bowl

65

4. Find your percentage error by using the following formula: 100(Estimate population- actual population)/actual population

18% percent error.

5. What concerns should a biologist have about a species' habits before (s)he uses this method to approximate the size of a population?

The species might have migrated to a different area, therefore the biologists are unable get the information they need.

Conclusion: How did you fulfill the purpose? What did you learn?

I learned how to estimate populations with different methods, like sampling, tagging and mark-recapturing.