Transcript
Please read carefully!
In case study #1 you are examining food webs and how parasites fit into food webs. You are provided with a couple different documents to read. BUT you are not required to read the entirety of either of these documents, nor are you required to answer all of the questions. Below you will find the requirements for this activity.
1. ?Open, download, and save both PDF files in this folder.
2. Download the Word Document entitled LastnameFirstinitial-Case1. Save this document by replacing the name with your name. (example: CielochaJ-Case1??????????)
3. In the document entitled Case Study, read Part I-Research Dilemma.
4. Answer the questions 1-3 to Part I by typing your responses in the Word Document (see page 2).
5. Read Part II-The New Question in the Case study.
6. Read pages 534-537 ("Introduction" through "How do we add parasites to food webs")
7. Answer questions 1-2 to Part II. Type these responses into your Word Document.
8. Answer the following question as well: How can Connie and Arthur incorporate parasites into their food web during their summer research project?
9. Read Part III-Building Food Webs in the Case Study.
10. Using the free-living organisms discussed in Part III reading, construct a food web. You may want to print page 6 and cut out the organisms or you can generate a web using boxes and arrows in your Word document. If you do it by hand, snap a picture and insert it into your Word document.
11. Add the life cycle of the parasite Ribeiroia ondatrae to your food web. Upload this picture as well.
[Note: Additional reading about this complex parasitic life cycles may be found at the following website—https://mathbio.colorado.edu/index.php/MBW:Modelling_the_dynamics_of_a_complex_life-cycle_parasite]
12. Answer the following questions:
How does the number of interactions compare when just observing free-living species vs. including parasitic species.
Which species is the most highly connected in the food web that includes parasites? Is this highly connect species free-living or parasitic?
What might happen to this food web if that species is removed?
13. Save your document and upload it to the Assignment on Blackboard.
Benjamin Crnkovich
Part I-Research Dilemma
Question 1. Figure 1 represents the drawing Dr. Olson sketched for Connie and Arthur. What are the different components of a food web diagram and what do they represent? What classification (e.g., primary producer, etc.) is given to the different species based on their connections to one another?
The arrows in a food web depicts the consumption of individuals as well as the transfer of energy between the two species. Written in the boxes are taxa names/names of the species. The species that has the arrow pointing to it would be considered a predator/consumer, and the box with the arrow pointing away would either be considered a producer or prey.
Question 2. Dr. Olson mentioned a list of organisms that have been the subject of previous research studies at Clear Lake. What additional information about these organisms is needed in order to determine their trophic level?
In order to determine a trophic level, you need to know the relationship between predator and prey, and where each species gets their energy. For example, some bacteria get their energy from the sun which makes them a primary producer, and some get their energy from consuming other species. Tertiary consumers often don’t have any predators above them, so that is how you would determine where along the food chain each species would fall.
Question 3. What types of methods do ecological researchers use to gain the information needed to build food webs?
They start by finding which species live in an ecosystem, and then turn them into “nodes”, and study the interactions between the two species (consumption, or lack there of) . Those interactions are represented by arrows between each species.
Part II-The New Question
1. What are some reasons that parasites have not previously been incorporated into food webs?
Generally, when making a food web one wouldn’t think to include something small as a parasite. Also, parasites aren’t considered “predators” because they don’t necessarily consume that which they are harming or inhabiting, hence, it is very easy to forget to include parasites.
2. Where in the food web do parasites fit? How are their interactions with other species represented?
Parasites could be put anywhere in the food web. They can be detrimental or critical to the survival of organisms, which could make them a producer or a “predator” of sorts, since they could harm their host. A food web represents how energy is transferred and who/what is consumed and in some cases, parasites give and/or take energy.
[Unnumbered Question 1] How can Connie and Arthur incorporate parasites into their food web during their summer research project?
They would need to figure out the interactions of the parasites and the species that are currently on their food web, and then decide whether they are harmful or helpful to the species.
Part III-Building Food Webs
Food web (free-living only)—computer generated or uploaded image
-1634760-762059804302119273-159025082200Food web (free-living + parasite)—computer generated or uploaded image
Final Questions:
[Unnumbered Question 2] How does the number of interactions compare when just observing free-living species vs. including parasitic species.
The number of interactions greatly increases.
[Unnumbered Question 3] Which species is the most highly connected in the food web that includes parasites? Is this highly connect species free-living or parasitic?
R ondetrae, it is parasitic.
[Unnumbered Question 4] What might happen to this food web if that species is removed?
Given the parasite causes an increase for predation on the infected individual, it may cause a shift in the consumption of individuals in the ecosystem, which may throw the ecosystem off balance. It would remove many arrows and interactions within the food web.
