Determining an Animal Population
Problem: How can you determine the size of an animal population?
Hypothesis: If you use a measuring technique or a sampling technique, then you can determine the size of the population.
Data:
Trial Total caught Number caught Number caught
with marks without marks
1 30 2 28
2 30 4 26
3 30 2 28
4 30 3 27
5 30 3 27
Averages 30 2.8 27.2
M= number initially marked CwM=average number caught during the trials with marks
Cw/oM= average number caught during trials without marks
Calculated Population Size = M x (CwM+ Cw/oM) = 20 x (2.8 + 27.2)
CwM 2.8
= 20 x 30 = 600 = 214.2857 = 214
2.8 2.8
Analysis:
1. Thinking Critically This experiment is a simulation. Explain why this type of activity is best done as a simulation.
This activity is best done as a simulation because it would be too difficult going into the wild to count the multiple moving animals which would also be difficult to mark or tag so to be tracked or even to get the correct amount into a pen.
2. Applying Concepts Give an example of how this technique could actually be used by a scientist.
Scientist could use this technique of predicting animal populations when trying to estimate the amount of an endangered species in a certain area.
3. Analyzing Data Compare the calculated to the actual population size. Explain why they may not agree exactly. What changes to the procedure would improve the accuracy of the activity?
The difference between the calculated population size and the actual population size was 13. The population sizes did not match up exactly because the probability of pulling out the amount of marked beans to match the results in every experiment would be highly doubtful. In order to make the results of the experiment more accurate we should repeat the experiment multiple times for a more plausible answer.
4. Explain why this technique is used more often with animals than with plants when calculating population size.
This technique is used more often with animals rather than with plants because when calculating population size animals move around rapidly so and accurate number is near impossible while plants do not move meaning the results can be calculated one by one.
5. Making Predictions Assume you were doing this experiment with living animals. What would you be doing in step 2? Step 3? Step 5?
Instead of step 2 the scientist would round up 20 animals and put them in an in closed place so not to escape. Instead of Step 3 the scientist would tag the animals using GPS or simply putting some kind of visual marker such as a bracelet. Instead of step 5 the scientist would release the animals back into the area then wait for the animals to scatter and run then round up 30 more animals from the surroundings.
Conclusion:
How can you determine the size of an animal population? Out of a small paper bag twenty beans were removed and marked with a sharpie. After that the beans were put back into the bag then shaken up then thirty of the beans were removed the observed to count how many were marked. Then putting all the beans back and recording to the data then repeated to find an average number of beans marked so later to be calculated to find the calculated population size. In trials 1 and 3 only two beans removed from the bag were marked while 4 and 5 had three and 2 had four beans marked out of thirty. The average number of beans caught marked was 2.8, this was calculated to a calculated population size of 214. The number calculated was 12 below the actual number of beans which was 226. The ability to calculate a reasonable close number to the actual number of beans total proved my hypothesis correct.
During this experiment I learned that scientists are able to estimate the population size from a series of trials and use simulations to approximate the size also. This experiment relates to what we are currently learning because it is showing the different factors that affect the populations growth such as crowding, waste, food, and water.
Hypothesis: If you use a measuring technique or a sampling technique, then you can determine the size of the population.
Data:
Trial Total caught Number caught Number caught
with marks without marks
1 30 2 28
2 30 4 26
3 30 2 28
4 30 3 27
5 30 3 27
Averages 30 2.8 27.2
M= number initially marked CwM=average number caught during the trials with marks
Cw/oM= average number caught during trials without marks
Calculated Population Size = M x (CwM+ Cw/oM) = 20 x (2.8 + 27.2)
CwM 2.8
= 20 x 30 = 600 = 214.2857 = 214
2.8 2.8
Analysis:
1. Thinking Critically This experiment is a simulation. Explain why this type of activity is best done as a simulation.
This activity is best done as a simulation because it would be too difficult going into the wild to count the multiple moving animals which would also be difficult to mark or tag so to be tracked or even to get the correct amount into a pen.
2. Applying Concepts Give an example of how this technique could actually be used by a scientist.
Scientist could use this technique of predicting animal populations when trying to estimate the amount of an endangered species in a certain area.
3. Analyzing Data Compare the calculated to the actual population size. Explain why they may not agree exactly. What changes to the procedure would improve the accuracy of the activity?
The difference between the calculated population size and the actual population size was 13. The population sizes did not match up exactly because the probability of pulling out the amount of marked beans to match the results in every experiment would be highly doubtful. In order to make the results of the experiment more accurate we should repeat the experiment multiple times for a more plausible answer.
4. Explain why this technique is used more often with animals than with plants when calculating population size.
This technique is used more often with animals rather than with plants because when calculating population size animals move around rapidly so and accurate number is near impossible while plants do not move meaning the results can be calculated one by one.
5. Making Predictions Assume you were doing this experiment with living animals. What would you be doing in step 2? Step 3? Step 5?
Instead of step 2 the scientist would round up 20 animals and put them in an in closed place so not to escape. Instead of Step 3 the scientist would tag the animals using GPS or simply putting some kind of visual marker such as a bracelet. Instead of step 5 the scientist would release the animals back into the area then wait for the animals to scatter and run then round up 30 more animals from the surroundings.
Conclusion:
How can you determine the size of an animal population? Out of a small paper bag twenty beans were removed and marked with a sharpie. After that the beans were put back into the bag then shaken up then thirty of the beans were removed the observed to count how many were marked. Then putting all the beans back and recording to the data then repeated to find an average number of beans marked so later to be calculated to find the calculated population size. In trials 1 and 3 only two beans removed from the bag were marked while 4 and 5 had three and 2 had four beans marked out of thirty. The average number of beans caught marked was 2.8, this was calculated to a calculated population size of 214. The number calculated was 12 below the actual number of beans which was 226. The ability to calculate a reasonable close number to the actual number of beans total proved my hypothesis correct.
During this experiment I learned that scientists are able to estimate the population size from a series of trials and use simulations to approximate the size also. This experiment relates to what we are currently learning because it is showing the different factors that affect the populations growth such as crowding, waste, food, and water.