Why Do You See Increases And Decreases In The Invasive Species Population? What Are The Implications Associated With These Alterations To The Ecosystem As A Whole
Student Instructions
In this lab, you will determine how an invasive species—the zebra and quagga mussel—affects other species in the freshwater lake. Use the animation to help you come up with an answer to the following:
- Why do you see increases and decreases in the invasive species population?
- What are the implications associated with these alterations to the ecosystem as a whole?
The Effects of Zebra and Quagga Mussels Introduced into a Freshwater Lake
As you have learned, population dynamics are caused by the biotic potential of the population and the effects of environmental resistance. When there is minimal environmental resistance impacting a population, it will exhibit a population explosion. One reason for minimal resistance could be factors that no longer regulate a population (e.g., predator decline or resource increases). Another reason for a population explosion is the introduction of an invasive species. Invasive species are species foreign to an ecosystem and are not immediately regulated by the environmental restraints of the particular ecosystem that they invade. This in turn allows their populations to grow seemingly uncontrolled and to displace other indigenous populations. Examples of such an invasive species into North America are dreissenid mussels, commonly known as zebra and quagga mussels. Their introduction into the Great Lakes has caused economic hardship and a reorganization of the ecosystem. This has led, in part, to pollution-causing effects that can be linked to an alga known as Cladophora.
Ecosystems are webs of intricately balanced interactions, what happens when a new species is introduced that uses a disproportionate share of the ecosystem’s resources?
Using the M.U.S.E. link, review the background information and animation to complete your report.
Use the Lab 5 worksheet for assignment instructions and data collection.
Hi Everyone,
For your lab report this week, you will investigate the impact and spread of invasive species.
One of these described in your MUSE lab activity is the Zebra Mussel.
Just as you have done for the previous assignments, you will first review the background information, then collect the data. Your study will involve measurements showing how the mussels have spread and how they have impacted native species in an aquatic environment.
You will find that the number of mussels increases for 13 years and then begins to decrease. You are asked to explain this in your report.
- Why do you see increases and decreases in the invasive species population?
- What are the implications associated with these alterations to the ecosystem as a whole?
Use the notes in the animation to review the food chain in this ecosystem. It will be very important to be able to describe which species are native and which are invasive. And to describe how even a native species, such as cladophora (algae) can result in ecological damage. Next, review Chapter 4 of your eBook and refresh your memory on how the members of an ecosystem interact and the upper limit of organisms that an ecosystem can support, known as the carrying capacity. As you collect your data consider how the cladophora increases along with the mussels. This happens because the mussels filter the water making it clearer. More sunlight reaches into the water’s depths allowing for better growth of these autotrophs. At year 13 we see a peak in both populations. I expect you will find that the huge number of mussels and the high level of cladophora deplete the Great Lakes ecosystem of nutrients.
Note that after 13 years the numbers of these detrimental organisms decreases, allowing the native populations to rebound.
If you would like a little more background information on the Zebra Mussel, this site has a good description with clear pictures:
http://www.protectyourwaters.net/hitchhikers/mollusks_zebra_mussel.php
Please use this outline to help you craft your report:
Purpose
State the purpose of the lab. This will be a sentence or two about assessing the impact of zebra mussels on the native populations of species in the Great Lakes.
Introduction
Include information on zebra mussels; where they come from; how they got to the US; what effect they have on native species.
Hypothesis/Predicted Outcome
A hypothesis is an educated guess. It needs to be a single statement that can be shown to be true or false through the results gleaned from this investigation.
It could be that zebra mussels will grow out of control.
It could be that zebra mussels will grow until they reach the carrying capacity of the ecosystem and then their population will crash.
Methods
Imagine you are the investigator. You will have to go to the Great Lakes and take samples to determine the population of all the species for which data has been collected.
For zebra mussels, they actually go diving to count and collect mussels. For fish species, they would perform a catch and release survey. Microscopic organisms would be analyzed through determining concentrations spectroscopically, etc.
Results/Outcome
Include the table. No further analysis is necessary.
Discussion/Analysis
In this section,
1) Summarize your results
2) Relate your results back to your hypothesis, either accepting or rejecting your prediction with an explanation of why you did so.
3) Explain the increase and decrease in population. Present an explanation of why the zebra mussels and cladophora increased and then suddenly decreased. Be sure to answer these questions:
Why do you see increases and decreases in the invasive species population?
What are the implications associated with these alterations to the ecosystem as a whole?
Deliverable Length:
1 page
Name:
Date:
Instructor’s Name:
Assignment: SCIE211 Phase 5 Lab Report
Title: Identifying Environmental Hazards
Instructions: You will write a 1-page lab report using the scientific method to answer the following questions:
· Why do you see increases and decreases in the invasive species population?
· What are the implications associated with these alterations to the ecosystem as a whole?
When your lab report is complete, post it in Submitted Assignment files.
Part I: Using the lab animation, fill in the data table below to help you generate your hypothesis, outcomes, and analysis.
| Years | Zebra and Quagga Mussel (density/m2) | Phytoplankton (µg/ml) | Zooplankton (µg/ml) | Cladophora Biomass (g/m2) | Foraging Fish (kilotons) | Lake Trout (kilotons) |
| 0 | 100 | 3 | 2 | 10 | 150 | 15 |
| 4 | 1000 | 2.5 | 1 | 100 | 100 | 10 |
| 7 | 2500 | 2 | 0.5 | 200 | 80 | 8 |
| 10 | 7500 | 1.5 | 0.25 | 600 | 50 | 5 |
| 13 | 15,000 | 1 | 0.1 | 700 | 25 | 2.5 |
| 15 | 7500 | 1.5 | 0.2 | 243 | 40 | 4 |
| 20 | 5000 | 1.75 | 0.4 | 136 | 60 | 6 |
Part II: Write a 1-page lab report using the following scientific method sections:
- Purpose
- State the purpose of the lab.
- Introduction
- This is an investigation of what is currently known about the question being asked. Use background information from credible references to write a short summary about concepts in the lab. List and cite references in APA style.
- Hypothesis/Predicted Outcome
- A hypothesis is an educated guess. Based on what you have learned and written about in the Introduction, state what you expect to be the results of the lab procedures.
- Methods
- Summarize the procedures that you used in the lab. The Methods section should also state clearly how data (numbers) were collected during the lab; this will be reported in the Results/Outcome section.
- Results/Outcome
- Provide here any results or data that were generated while doing the lab procedure.
- Discussion/Analysis
- In this section, state clearly whether you obtained the expected results, and if the outcome was as expected.
- Note: You can use the lab data to help you discuss the results and what you learned.
Provide references in APA format. This includes a reference list and in-text citations for references used in the Introduction section.
Give your paper a title and number, and identify each section as specified above. Although the hypothesis will be a 1-sentence answer, the other sections will need to be paragraphs to adequately explain your experiment.
When your lab report is complete, post it in Submitted Assignment files.
