Something's Fishy Lab
Independant Variable: Population size
Dependant Variable: Accuracy
Control Variable: Same proccess
Problem: How effective is population tagging at estimating population size?
Hypothesis: It is somewhat effective, but not very accurate.
Materials: Goldfish crackers ( colored and uncolored), Plate, Zip-Lock bag
Procedure:
Dependant Variable: Accuracy
Control Variable: Same proccess
Problem: How effective is population tagging at estimating population size?
Hypothesis: It is somewhat effective, but not very accurate.
Materials: Goldfish crackers ( colored and uncolored), Plate, Zip-Lock bag
Procedure:
- Obtain a bowl with your fish.
- Do NOT count the number of fish in your pond yet!
- Have one member of your group remove a large handful of fish.
- Count the number of fish you just removed and write it in the table below.
- Replace these fish with “tagged” fish (in this case, colored “fish”)
- Mix your pond well to redistribute the tagged fish among the other fish.
- One member at a time (and without looking), remove a handful of fish and record the number of total fish in the sample, the number of tagged fish, and figure out the percentage of tagged fish. (see chart)
- Return your handful to the bowl!!
- Continue with this until you have taken 20 samples.
Data Table:
QUESTIONS
1. What is the mean (average) of your percent tagged fish from your 20 samples? 36%
2. Using the following formula, determine an estimated population for your pond: 83
3. Now, actually count the number of fish in your bowl: 100 fish
4. Find your percentage error by using the following formula: -17%
5. Does this method appear to be an effective way to assess population size? Why or why not? No, because they a fish lives in is different than other fishes. Also, fishes migrate from habitat to another and changes the population size.
6. What concerns should a biologist have about a species’ habits before (s)he uses this method to approximate the size of a population? The biologist need to look at their migrating habits, their habitat, and reproduction rate
CONCLUSION
My hypothesis was correct because tagging did give me an idea of how many fishes were in my pond, which was 83, but it was not accurate because the actual count was 100 fish in the pond. So, as you can see, this method is not very accurate, though it does give you an idea of how many fish you have in your pond. This method can still be used to find, or give an idea of, a certain population in a an area of an ecosystem, such as tropical forests or deserts.
1. What is the mean (average) of your percent tagged fish from your 20 samples? 36%
2. Using the following formula, determine an estimated population for your pond: 83
3. Now, actually count the number of fish in your bowl: 100 fish
4. Find your percentage error by using the following formula: -17%
5. Does this method appear to be an effective way to assess population size? Why or why not? No, because they a fish lives in is different than other fishes. Also, fishes migrate from habitat to another and changes the population size.
6. What concerns should a biologist have about a species’ habits before (s)he uses this method to approximate the size of a population? The biologist need to look at their migrating habits, their habitat, and reproduction rate
CONCLUSION
My hypothesis was correct because tagging did give me an idea of how many fishes were in my pond, which was 83, but it was not accurate because the actual count was 100 fish in the pond. So, as you can see, this method is not very accurate, though it does give you an idea of how many fish you have in your pond. This method can still be used to find, or give an idea of, a certain population in a an area of an ecosystem, such as tropical forests or deserts.