Chapter+Five

= =

**Chapter Five**

Please watch the video below...then the first five of you are going to create jeopardy style answers...and the remainder of you are going to create the questions to go with them. media type="youtube" key="LBagx9Qhdx8" height="315" width="420"

Max Blazon: Freddie, Alex Q: The energy for most ecosystems comes from this main source: What is the sun? Q: This percentage of energy is lost at each level of the food chain: How much is 10%? Q: This diagram explains the ten percent rule and the transfer of energy in an ecosystem: What is an energy pyramid? Q: This animal is considered a primary consumer: What are insects? Q: At each level of the food chain, this source of life is lost: What is energy? Q: When this piece of a food chain is removed, all organisms are affected: What is any link in any food chain?

media type="youtube" key="KGal4qAQbRg" height="315" width="420" align="right"

Please watch the brief video on the left. I would like the the first five of you who get to this assignment to create a question for this video. Then the remainder of you should answer those questions.

Freddie: Q: What happens when one organism is removed from the food chain by outside variables? A bug brought from Europe for example Q: Are there ecosystems without the top level of the food chain?

Nick: Q: What kind of changes would the influence humans have over ecosystems make to the flow of energy? Kelcie: Q: If either the producer, primary consumer, or secondary consumer was taken out of the equation, do you think that the environment could eventually adapt to live without one of them? Catie: I think that this is a good question! I believe that it would be difficult to adapt to live without one of them, because when one link is taken out of an environment, it affects everything else and the equilibrium is set off balance. Just like with the Cats from Borneo, everything in the environment was impacted negatively because of one action. I think it would be impossible for an environment to adapt to live without the producers, because producers are at the very base of the food chain. The producers are the only organisms that have the ability to take energy from the sun and manipulate it so that it can be used by other organisms. Consumers cannot make their own energy through photosynthesis. They must eat the autotrophs so that they can obtain energy to survive. Without producers, an environment would not be able to survive. If a secondary consumer was taken out of the equation, there would be an exponential growth of primary consumers because they would no longer have a predator, and as a result of more primary consumers, the producers would diminish. It's difficult to adapt when an entire part of the food chain is taken out of the equation.

Catie : Q: Can you explain the ten percent rule and give an example?

Please visit the following website to see how the simple view of predator/prey relationships evolve into much more complex relationships. I would like each of you to choose one of these models to explain as best you can.

Max Blazon: The General Predator-Prey Model: The population of a predator and its prey (ie. a fox and rabbit relationship) are dependent upon one another. As the population of rabbits increases to a certain point, the population of foxes will increase as well. Yet overpopulation and the carrying capacity of an environment bring down the rabbit population as well as the fox population. Both will eventually rebound though. With less predators, the rabbits will increase and with more prey the foxes will increase. Alex: **Kermack-McKendrick Model:** This model refers to the idea of herd immunity. In this case, the prey are organisms that are susceptible to the disease, and the predators are infectives. A susceptible organism can become and infective, and the infective can eventually be rid of by death, quarantine, or cure. The population of infectives (predators) will grow as they infect susceptibles (prey). However, if they cannot infect, then they will eventually die out, reducing the predator population and allowing the prey population to grow. The model reflects the fact that the susceptible population can be reduced to a level below which infectives will not increase. Catie: ** Jacob-Monod Model: ** This model represents the interaction between predators and their prey, but it also accounts for organisms taking up nutrients (like bacteria). These organisms, have a limited uptake rate, so the the Jacob-Monod Model accounts for these rates. For example, this model is used to describe, when there is a continuous removal of nutrient and feeders, and a continuous supply of nutrient, and it helps balance the bacterial growth with wash out of feeders. This model is important because it does account for bacteria, and bacteria can be important when modeling the relationship between predators and prey because bacteria are also present in the environment and can have an effect.

Please read the attached article about ecological disturbance. Think about an ecological disturbance that you have either seen or read about and then try to describe/analyze that disturbance at a deeper level.