Population of Squirrels Lab
Problem: How does the competition between native and invasive squirrels affect population size?
Hypothesis: The population of red squirrels will decrease when the invasive, more fit gray squirrels are introduced in the ecosystem over time.
Independent Variable: TIME. Control the times that you measure the squirrel populations.
Dependent Variable: The population of the red and gray squirrels
Research
Data Table / Graph: At bottom
Conclusion:
1. It was easiest for the red squirrels to find food for the first 8 years(because there was barely any competition), but after that it dipped drastically. The worst year was the 19th when the squirrels were running dry on resources
2. Organisms in the same population competed for resources when they were running dry and when they had the same niche. For example the red squirrels started competing for resources when the resources were running low and they were at their brink
3. Resources are affected by competition because the more competition that there is for the same resource, the more that the resources start running low
4. They would need to change either their shelter or their main source of food. That would make them survive against the invasive species.
C-E-R Conclusion
Claim: The population of red squirrels will decrease when the invasive, more fit gray squirrels are introduced in the ecosystem over time. This would force the red squirrels to adapt or to die out.
Evidence: The red squirrels were prospering for the first 8 years when they had 87 squirrels During that 9th year, the invasive gray squirrels started competing for resources. The red squirrel's population dipped down to 88 squirrels that year. Then during the 10th year, there were only 62 red squirrels left and the number of gray squirrels had doubled to 20 squirrels. Only 5 years later, the red squirrel's population dipped down to 31 squirrels while the gray squirrels number's had increased to 156 squirrels. During the 20th year, the red squirrels eventually died out and the gray squirrels's population was at 178 squirrels.
Reasoning: Red squirrels and gray squirrels both compete for the same resources. This forced competition among the two species and eventually killed off the red squirrels. This also increased the coyotes's numbers since they did not have to compete for the same resources as the squirrels, and the squirrels were also good sources of food. The coyotes were at their least at year 8 when the gray squirrel's had just been introduced. If the squirrels start running out of resources they will be forced to adapt or die out, therefore also reducing the coyote's population. During the 8th year the red squirrel's to gray squirrel's population ration was 98:6. Only 7 years later, the numbers had almost completely gone in the gray squirrel's favor with the ratio from red to gray squirrel's being 31:156.
Problem: How does the competition between native and invasive squirrels affect population size?
Hypothesis: The population of red squirrels will decrease when the invasive, more fit gray squirrels are introduced in the ecosystem over time.
Independent Variable: TIME. Control the times that you measure the squirrel populations.
Dependent Variable: The population of the red and gray squirrels
Research
- The red squirrel is an omnivorous rodent
- Red squirrels can live for up to 7 hours
- The gray squirrel is a scatter hoarder: it hides food underground and digs it up for later use
- Eastern Gray Squirrels build nests at the top of trees to get away from predators on the ground
- Coyotes do travel in groups, but they are known to hunt in pairs
- Coyotes hunt during the night
Data Table / Graph: At bottom
Conclusion:
1. It was easiest for the red squirrels to find food for the first 8 years(because there was barely any competition), but after that it dipped drastically. The worst year was the 19th when the squirrels were running dry on resources
2. Organisms in the same population competed for resources when they were running dry and when they had the same niche. For example the red squirrels started competing for resources when the resources were running low and they were at their brink
3. Resources are affected by competition because the more competition that there is for the same resource, the more that the resources start running low
4. They would need to change either their shelter or their main source of food. That would make them survive against the invasive species.
C-E-R Conclusion
Claim: The population of red squirrels will decrease when the invasive, more fit gray squirrels are introduced in the ecosystem over time. This would force the red squirrels to adapt or to die out.
Evidence: The red squirrels were prospering for the first 8 years when they had 87 squirrels During that 9th year, the invasive gray squirrels started competing for resources. The red squirrel's population dipped down to 88 squirrels that year. Then during the 10th year, there were only 62 red squirrels left and the number of gray squirrels had doubled to 20 squirrels. Only 5 years later, the red squirrel's population dipped down to 31 squirrels while the gray squirrels number's had increased to 156 squirrels. During the 20th year, the red squirrels eventually died out and the gray squirrels's population was at 178 squirrels.
Reasoning: Red squirrels and gray squirrels both compete for the same resources. This forced competition among the two species and eventually killed off the red squirrels. This also increased the coyotes's numbers since they did not have to compete for the same resources as the squirrels, and the squirrels were also good sources of food. The coyotes were at their least at year 8 when the gray squirrel's had just been introduced. If the squirrels start running out of resources they will be forced to adapt or die out, therefore also reducing the coyote's population. During the 8th year the red squirrel's to gray squirrel's population ration was 98:6. Only 7 years later, the numbers had almost completely gone in the gray squirrel's favor with the ratio from red to gray squirrel's being 31:156.