Process of Science
Effects of Environmental Changes on Population Professor
Institution
Date
” How Do Environmental Changes Affect a Population Lab” worksheet by taking notes from the investigation and answering the questions associated with the investigation.
How Do Environmental Changes Affect a Population?
Lab Notebook
Global Warming Data Table
Number of:
Size
Color
Large
Medium
Small
Black
Brown
Parental generation
3
22
2
22
3
10th generation
0
20
5
25
0
20th generation
0
10
15
25
0
30th generation
0
3
22
25
0
Graph your Global Warming data, using this key:
Large leafhoppers = •
Medium leafhoppers = O
Small leafhoppers = •
Black leafhoppers = X
Brown leafhoppers = X in color
Predator Change Data Table
Number of:
Size
Color
Large
Medium
Small
Black
Brown
Parental generation
1
21
2
3
22
10th generation
1
23
1
10
15
20th generation
1
23
1
15
10
30th generation
0
25
0
22
2
Graph your Predator Change data:
Vegetation Change Data Table
Number of:
Size
Color
Large
Medium
Small
Black
Brown
Parental generation
2
22
1
22
3
10th generation
1
23
1
23
2
20th generation
0
25
0
24
1
30th generation
0
25
0
25
0
Graph your Vegetation Change data:
Pesticide Application Data Table
Number of:
Size
Color
Large
Medium
Small
Black
Brown
Parental generation
02
22
1
22
3
10th generation
05
20
0
24
1
20th generation
10
15
0
25
0
30th generation
23
02
0
25
0
Graph your Pesticide Application data:
Questions
1. What role does genetics play in the variation seen in this leafhopper population?
According to Darwins theory of natural selection, the organisms and individuals which are better adapted to their environment are more likely to survive and reproduce compared to those less adopted. The favored characteristics tends to build up in the population leading to evolution. Within the leafhopper population, thy have got different colors and sizes. The difference in coloration may make the leafhopper to camouflage from the predators. Offspring with small bodies will have advantage over the big bodied ones since they require fewer resources to survive and if the environment change different traits may be of advantage.
2. Note the results from the 20th generation under global warming conditions. Before continuing with the 30th generation, predict the population composition of the 30th generation.
The small leafhoppers and black color leafhopper survive when there is alteration in global warming, while the bigger sized leafhopper and the brown in color are adversely affected and their population drastically reduces. If global warming continues, then at this rate the middle sized leafhoppers will probably be reduced and finished. Only the small leafhoppers will remain prominent unlike the parental generation where the bigger population was made up by middle sized leafhoppers.
3. What happened to the proportion of each type of leafhopper in subsequent generations under global warming conditions? Suggest a reason why the traits of the 30th generation make this population better adapted to its altered environment.
The population of the large sized, medium sized and the brown colored leafhopper drastically reduce. The change in traits helps the leafhopper to adapt well. The leafhoppers becomes smaller in order to survive from other animals and birds which can feed on them. The brown and large did not survive because their color was so noticeable compared to the rest and therefore could be spotted easily by the predators while being small made it so difficult for the predators to spot them.
4. Why would you expect a change in predators to cause a difference in the types of leafhoppers being selected?
The change of predators from birds to snakes I expect to favor the survival of the leafhoppers. This is because of the kind of locomotion depicted by the two predators. Birds as flying predators could easily spot the leafhopper from a distance and clear their population easily compared to the snakes which are scrawling predators. Having also in mind that leafhoppers are flying insects and cannot easily be spotted by a scrawling predator. The introduction of snakes therefore facilitated the increase in population of leafhopper.
5. Note the differences between the parental, 10th and 20th generations when the predator changed from a bird to a snake. What evidence supports the view that leafhopper size is not affected by a change in predators?
The population of the leafhopper is not affected by bringing a different predator in the ecosystem. This is because different predators have different skills and adaptations to catch their prey. Though the population of the brown are drastically affected and reduces steadily, this is because they are easily spotted by the predator compared to the black colored ones.
6. What happened to the proportion of each type of leafhopper in subsequent generations when the predator changed from a bird to a snake? Suggest a reason why the traits predominant in the 30th generation make this population better adapted to the change in predators.
The population of the large leafhopper increased drastically and those of the medium reduced. Also, the black are much favored compared to the brown population because they can easily camouflage the predator. The small leafhoppers are not much affected.
7. Describe some human activities around your school that could have influenced the natural vegetation in the area.
Deforestation- this is the cutting down of trees by human beings. This has been done over and over again and with the improvement of equipment there is drastically increase in tree cuttings leading to degradation of vegetation, imbalance of nutrients, flooding and migration of animals.
Pollution- this is caused by machines used by human beings which emit toxic gases, irritants and carcinogen particles which create air pollution. Humans have also dumped large amounts of toxic pesticides which ends up poisoning the ecosystem.
8. Note the differences between the parental and the 30th generations. What happened to the proportion of each type of leafhopper when the vegetation changed? Suggest a reason why the traits of the 30th generation make this population better adapted to its altered environment.
In the 30th generation, the leafhopper are much adapted to the changes in environment and the black and medium are much favored compared to the colored and the small leafhopper. This generation can easily migrate to areas with favorable environments hence maintaining their population. They can also hibernate to protect them from adverse environmental conditions.
9. Identify some major sources of pesticides in your area.
The main source of pesticides are humans. Large amount of production of synthetic materials began way back and the majority are used in agriculture. Most of the pesticides are from farms which are used to eradicate the pests which affect the growth of plants. When applied, they evaporate in the air, some enter in the soil and some are swept away by flowing water. At this moments they get into contact with the targeted pesticides and kill their population.
10. What happened to the proportions of leafhoppers in each subsequent generation when pesticides were added to the environment? Explain why all the leafhoppers were not killed by the pesticide application.
Pesticide application reduces the population of the leafhopper in all the generation but the small ones are not much affected by this because of their small size which enable them not to easily get into contact with the pesticide. After some subsequent application, all the leafhopper are not killed because they have gotten used to the pesticide and mutation has taken place within their bodies making them more resistant.
Reference
Bijlsma, R., & Loeschcke, V. (1997). Environmental stress, adaptation, and evolution. Boston, Mass: Birkhäuser Verlag
Hoffmann, A. A., & Parsons, P. A. (1997). Extreme environmental change and evolution. Cambridge: Cambridge University Press.
Miller, G. T., & Spoolman, S. (2009). Living in the environment: Concepts, connections, and solutions. Belmont, CA: Thomson Brooks/Cole
National Research Council (U. S.). (2011). A framework for K-12 science education: Practices, crosscutting concepts, and core ideas. Washington, D. C: National Academies Press
Tweed, A. (2009). Designing effective science instruction: What works in science classrooms. Arlington, Va: NSTA Press, NSTA Press, National Science Teachers Association/McREL.