Something Fishy
Title: How to estimate a population by using sampling and tagging method?
Purpose: The purpose of this lab is to estimate the size of a sample population using the mark-recapture technique.
Background: Sampling is a method used to estimate a population size, it takes place by counting organisms in a few small areas and the result is used to estimate the population to the entire area. The other method is tagging which is frequently used in area with butterflies and fish. In this method you have to track migration patterns, health and range to determine population numbers. You are suppose to take random samples and tag them, then you let them redistribute themselves after you determine the percent tagged and hypothesize the whole population of the area.
Procedure:
1.obtain a bowl with your "species" in it. ("fish crackers")
2. Do Not count the number of fish in the pond yet.
3. Have on remember of your group remove a large handful of fish.
4. Count the number of fish you just removed and replace these fish with "tagged" fish (colored fish)
5. Mix your pond well to redistribute the tagged fish among the other fish
6. One member at a time(randomly/without looking), remove a handful fish and record the number of total fish in the sample, the number of tagged fish, and figure out the percentage of tagged fish (chart below)
7. Return your handful to the bowl. continue with this until you have taken 20 samples.
Purpose: The purpose of this lab is to estimate the size of a sample population using the mark-recapture technique.
Background: Sampling is a method used to estimate a population size, it takes place by counting organisms in a few small areas and the result is used to estimate the population to the entire area. The other method is tagging which is frequently used in area with butterflies and fish. In this method you have to track migration patterns, health and range to determine population numbers. You are suppose to take random samples and tag them, then you let them redistribute themselves after you determine the percent tagged and hypothesize the whole population of the area.
Procedure:
1.obtain a bowl with your "species" in it. ("fish crackers")
2. Do Not count the number of fish in the pond yet.
3. Have on remember of your group remove a large handful of fish.
4. Count the number of fish you just removed and replace these fish with "tagged" fish (colored fish)
5. Mix your pond well to redistribute the tagged fish among the other fish
6. One member at a time(randomly/without looking), remove a handful fish and record the number of total fish in the sample, the number of tagged fish, and figure out the percentage of tagged fish (chart below)
7. Return your handful to the bowl. continue with this until you have taken 20 samples.
1. What is the mean(average) of your percent tagged fish from your 20 samples?
4
2.Using the following formula, determine an estimated population for your pond:
20*19/4=95
3.Now, actually count the number of fish in your bowl
74
4. Find your percentage error by using the following formula
100*(95-74)/74=28%
5.What concerns should a biologist have about species' habits before he uses this method to approximate the size of a population?
Biologists should be concerned about the species migration patterns, health and range to get better results
Conclusion:
My results showed that I had 28% error which is not that close to the actual numbers so the possibilities for my errors may be me counting the fish wrong, or something similar to that. The lesson I learned from this lab is in order to get the estimated population of an area you don't have to count all of the organisms but instead you can use sampling or tagging method to figure out the estimated population.
4
2.Using the following formula, determine an estimated population for your pond:
20*19/4=95
3.Now, actually count the number of fish in your bowl
74
4. Find your percentage error by using the following formula
100*(95-74)/74=28%
5.What concerns should a biologist have about species' habits before he uses this method to approximate the size of a population?
Biologists should be concerned about the species migration patterns, health and range to get better results
Conclusion:
My results showed that I had 28% error which is not that close to the actual numbers so the possibilities for my errors may be me counting the fish wrong, or something similar to that. The lesson I learned from this lab is in order to get the estimated population of an area you don't have to count all of the organisms but instead you can use sampling or tagging method to figure out the estimated population.