Understanding Ecosystem Dynamics: Producers and Herbivores
School
Argonaut High**We aren't endorsed by this school
Course
BS 100
Subject
Biology
Date
Dec 12, 2024
Pages
8
Uploaded by KidFog12936
Directions:On the main page, you will see two Interactive Ecology Labs listed including the name of the Lesson, a Challenge, two Steps and For your consideration. Click on the Challenge for the first lesson: The Producers. Open the Simulator in another tab, and following the directions in the two steps. Use the data tables below to fill in your results. Finally, answer the questions posed by each lesson. Next, do the same for the Food Web Interactive Lab. Make sure you do the producer lab before the food web lab.DATA TABLE: ECOLOGYLESSON 1: The ProducersLesson 1: Step 1Plant APlant BPrediction: starting population5,0005,000Prediction: ending population7,000 or 8,0003,000Starting population5,0005,000Ending population10,0000Lesson 1:Step 2Plant APlant BHerbivore APrediction: starting population5,0005,000500Prediction: ending population3,0006,0002,000Starting population5,0005,0001,000Ending population3,3354,9982,055Step One Questions:1.What assumptions does this model make about co-dominance as well as the general terrain of the ecosystem?
The model made the same assumption that I made, that both plants can coexist and compete equally, with no immediate advantages. However, the result started off well but plant A outcompeted the other over time. Which indicates that coexist long-term is highly unlikely in this system. 2.Do you find one producer to be dominant? Why might one producer be dominant over another?Yes, plant A ending at 10,000 is the dominant, while plant B dropped all the way to 0 being completely outcompeted. Plant A may have had some traits that gave it a competitive advantage, such as faster growth or better absorption of resources. Another thing could that plant A just monopolized critical resources better then plant B. Step Two Questions:1.Does adding the herbivore establish a more equal field? Is one producer still dominant over the other? Why might one producer be dominant over another?Adding an herbivore did help establish a more equal field. Neither plant A nor plant B completely dominated over one other. However, plant B is slightly more dominant, with an ending population of 4,998
compared to plant A’s 3,335. Well, since the herbivores preferred to each plant A, it reduced its population more significantly. 2.If the simulation included decomposers, how would your current results change?If decomposers were included in the simulation, they would recycle nutrients from plant and herbivore waste back into the soil. This would likely lead to a more stable and balanced ecosystem, as nutrient availability would support both Plant A and Plant B populations.3.How do producer population numbers with the presence of an herbivore compare to the primary colonizer model?In the primary colonizer model, one producer plant A completely dominated, reaching 10,000, while the other plant B went extinct. Withthe herbivore present, both plants survive, and their populations remain closer in number, although plant B is still slightly dominant. This shows that introducing an herbivore prevents one producer frommonopolizing resources, leading to greater diversity and balance in the ecosystem.Final Questions:
From what you have learned in this module and in the video, how are humans contributing to the creation of a vastly rapid form of succession? In other words, how are we speeding up the effects of the competitive exclusion principle and thereby altering the outcome of that ecosystem's natural successionWe are speeding up succession by disrupting ecosystems in various ways.This including deforestation, pollution, and introducing invasive species allalter natural habitats, allowing fast-growing or hardy species to take over and push out native ones. We also contribute to climate change, which creates conditions that favor certain species, like those that thrive in warmer or more disturbed environments. These actions force ecosystems to change more rapidly than they would naturally, speeding up the effects of the competitive exclusion principle, where one species outcompetes another for resources, and preventing ecosystems from developing in theirnatural, slower succession process. In the end, we’re slowly destroying theEarth little by little, all because of our impact on the environment.DATA TABLE: ECOLOGYLESSON 2: Food WebLesson 2:Step 1(X, , or )Plant AHerbivore AOmnivore ATop PredatorPredictionSurvive Survive andSurvive Survive and
but numbers will decrease increase in numbersand increase innumbersincrease in numbersSimulation 1Simulation 2Lesson 2:Step 2(X, , or )Plant APlant BPlant CHerbivoreAHerbivoreBHerbivoreCOmnivoreAOmnivoreBTopPredatorPredictionDecreaseDecreaseIncreaseIncreaseIncreaseIncreaseDecreaseDecreaseIncreaseSimulation 1XXSimulation 2XXModificationsmadeHerbivore A & C eat plant AHerbivore A & B eat plant BHerbivore B & C eat plant cOnly eatsplants A & B Only eatsplants A & BOnly eatsplants A & BEats Herbivore A & B Eats Herbivore B & CEats omnivore AStep One Questions:1.Was your prediction correct? How did you arrive at your prediction? What differences were there between your predictionand the simulation?The prediction was mostly correct, with Herbivore A and Omnivore A both increasing, as expected. However, the Top Predator population decreased, which wasn’t anticipated. I thought all species would survive since there was enough prey, but something limited the predator population, possibly due to increased competition, lack of sufficient prey, or other environmental pressures. Plant A decreased, as expected,due to herbivory, but overall, the Top Predator didn’t behave as predicted.2.What would happen to this imaginary ecosystem if the producerswere to die out?If the producers died out, the entire ecosystem would likely collapse. Producers form the foundation of the foodweb, and without them, herbivores would have no food source. This would lead to a domino effect where herbivores, omnivores, and top predators would also die off due to the loss of food.
3.Did any of the species increase in number? What could account for this increase? Which species decreased in number and what might account for this decrease?Yes, Herbivore A and Omnivore A both increased in number due to the availability of food sources from the producers and each other. These species had enough resources to survive and reproduce. The Top Predator decreased in number, possibly due to insufficient food or predation pressure, which limited its population growth. Plant A also decreased, because it was consumed by herbivores faster than it could regenerate, leading to a population decline.4.Which populations would benefit the most from the presence of decomposers?Both Herbivore A and Omnivore A would benefit the most from decomposers.Step Two Questions:1.Was your prediction correct? How did you arrive at your prediction? What differences were there between your predictionand the simulation?My prediction was somewhat correct in terms of how plant populations would decrease (other than plant c) and herbivore populations would increase. I predicted that Plant A and Plant B would decrease due to herbivory,and that Plant C would increase just because why not. The herbivores were expected to increase in number. However, in the simulation, all plant species decreased, and Herbivore A, Herbivore B, and Herbivore C all did the opposite of what I predicted and decreased. Also, insteadof my omnivores decreasing, they simply died out due to a lack of sufficient food sources.
2.Were you able to modify the parameters so that each species survived? Explain how you decided what changes to make.Yes, I was able to modify the parameters to ensure the survival of all species. It took several tries, but I made sure that each herbivore ate at least two plants, so every plant had two herbivores feeding on it. I also ensured that my omnivores ate two herbivores, with Herbivore 1 and Herbivore 3 thriving, and both omnivores sharing Herbivore 2. The tricky part came when I realized that Omnivore 2 kept dying out when the Top Predator was eating it. I fixed this by limiting the Top Predator’s diet toonly Omnivore 1, which decreased its chances of survival but still allowed it to last. It’s funny, though, that Omnivore 2 almost didn’t survive, even with these changes.3.Which way does energy flow and how does eating an organism result in energy transfer?Energy flows from the plants to herbivores, then to omnivores, and finally to top predators. When an organism is eaten, the energy stored in its body is transferred to the consumer thanks to the first law of thermodynamics. For example, Herbivore A eats Plant A, absorbing the plant’s energy. Then, Omnivore A eats Herbivore A, gaining the energy the herbivore had from the plant. This continues up the food chain, with each level transferring energy to the next. The Top Predator consumes Omnivore A, gaining the energy stored in the omnivore. Energy moves through the food web in this way, with each organism passing on the energy it has consumed to the next level.Final Questions:1.How does a natural ecosystem offer suggestions toward a more economical and eco-friendly human model?
Natural ecosystems operate efficiently by recycling resources, minimizing waste, and using renewable energy. Plants capture solar energy, and decomposers break down organic matter, returning nutrients to the soil. Many of these processes suggest that our systems could be more sustainable by focusing on recycling, reducing waste, and relying on renewable resources, like solar or wind energy. By us mimicking nature's closed-loop processes, humans could create more eco-friendly models in agriculture, energy production, and waste management, reducing environmental impact.2.How do humans affect the greater food web? In this model, how could humans who do not live in the ecosystem still manage to alter the flow of energy within the web? We have a SIGNIFICANT impact on the food web by altering habitats, hunting, farming, and polluting. Even if we aren't directly part of an ecosystem, activities like urbanization, overfishing, or releasing pollutants can disrupt the flow of energy in the web. For example, cutting down forests not only removes trees that act as producers but also displaces animals that rely on those habitats. Hunting and overfishing remove key species, particularly top predators or important herbivores, which can create imbalances in the ecosystem. When predators are removed, prey species may overpopulate and overconsume vegetation, damaging plant life and affecting the entire food web. Additionally, some of our activities like polluting water and air with chemicals, plastics, and waste can poison both plant and animal populations, disrupting their ability to thrive and reproduce. We don’t have to be directly involved in an ecosystem to have an impact, these actions still affect energy flow by changing the species composition, limitingthe availability of resources, and disrupting predator-prey relationships.