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.
Procedures:
1. Get a bowl with your "species" (in this case, it if "fish" crackers)
2. Do not count the number of fish yet.
3. Have one member remove a handful of fish. Write the number here: 12
4. Count the number of fish you remove, and replace it with tagged fish (colored fish).
5. Mix the pond to distribute the fish.
6. 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.
7. Return to the bowl and repeat the process 20 times
2. Do not count the number of fish yet.
3. Have one member remove a handful of fish. Write the number here: 12
4. Count the number of fish you remove, and replace it with tagged fish (colored fish).
5. Mix the pond to distribute the fish.
6. 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.
7. Return to the bowl and repeat the process 20 times
Data:
Question:
1. What is the mean (average) of your percent tagged fish from your 20 samples?
2. Using the following formula, determine an estimated population for your pond:
Population Size = total number captured x number marked / total number captured with mark
40
3. Now, actually count the number of fish in your bowl: fish
65
4. Find your percentage error by using the following formula: %
100 x (Your estimate of population - Actual size of population) / (Actual size of population)
38%
5. What concerns should a biologist have about a species’ habits before (s)he uses this method to approximate the size of a population?
They should know:
- Do the species live in clusters or separated?
- Do they stay in a small area or a large area?
- Are they nocturnal or diurnal?
- Life span?
2. Using the following formula, determine an estimated population for your pond:
Population Size = total number captured x number marked / total number captured with mark
40
3. Now, actually count the number of fish in your bowl: fish
65
4. Find your percentage error by using the following formula: %
100 x (Your estimate of population - Actual size of population) / (Actual size of population)
38%
5. What concerns should a biologist have about a species’ habits before (s)he uses this method to approximate the size of a population?
They should know:
- Do the species live in clusters or separated?
- Do they stay in a small area or a large area?
- Are they nocturnal or diurnal?
- Life span?
Conclusion:
How did you fulfill the purpose? What did you learn?
I applied the technique that biologist use to approximate the population size, by capturing and tracking a handful of Goldfish. Errors in my experiment could have from not shuffling the fish around enough, grabbing too many or not grabbing enough. I learned that counting population size is incredibly difficult. My data was completely inaccurate, which makes me question if this happens in real life and do they repeat the process again to grantee their numbers are as close to correct as possible.
I applied the technique that biologist use to approximate the population size, by capturing and tracking a handful of Goldfish. Errors in my experiment could have from not shuffling the fish around enough, grabbing too many or not grabbing enough. I learned that counting population size is incredibly difficult. My data was completely inaccurate, which makes me question if this happens in real life and do they repeat the process again to grantee their numbers are as close to correct as possible.