SCI-204-10938 Bodus Environmental Science with Lab

week 3

 

iLab 3 of 7: Threatened and Endangered Species, Alien Species 

  

Exercises

Exercise 1. Explain the Biomass Pyramid (in relation to mass and energy usage) using ONE of the following three ecosystems: Eastern Deciduous Forest, Tropical Rain Forest, or Grassland. Draw a food chain, food web, and predict a predator/prey relationship for your particular ecosystem.

Exercise 2. The eruption of Mount St. Helens is infamous for the destruction wrought on the surrounding areas; however it has also given rise to the development of a host of new ecological systems. View the following pictures and animation from NASA: http://www.nasa.gov/vision/earth/lookingatearth/mtsthelens_1001_prt.htm Search the Internet for additional information describing the Mount St. Helens recovery that has occurred since the eruption. List your references!Exercise 3. Musk Oxen are protected in Alaska. The rule of 70 states that if you divide 70 by the annual percentage increase of a population, the population will double in the resulting years. For example, a population increase of 7% per year results in a doubling in 10 years. Suppose the oxen population in Alaska is free of hunters and other predators and is increasing at a rate of 23.33% per year. (Oxen cows sometimes twin but most have single births and are known to be prolific breeders.) If you started with 100 oxen, what would the population be after three years? After six years? Suppose the carrying capacity of the ecosystem was 500 oxen — what would happen to the Musk Oxen population after the six year period? What might happen if the environment was not free of predators? WHY?