Where Have All the Creatures Gone?
This ecosystem unit focuses on organisms’ needs for survival and what happens when those needs are not met. Throughout the unit, students investigate a specific population change: the decrease in the trout population in the Great Lakes from 1930 to 1990. Because the sea lamprey, as an invasive species in the Great Lakes, is such a fascinating organism, this particular case of population change engages students in learning core science ideas that they can then apply to changes in their local environments or elsewhere. Over the course of their investigation, students learn why food is important, what structures different organisms have in order to eat and reproduce, what the possible relationships are between organisms (e.g. competition, predator/prey, producer/consumer) and what abiotic factors affect ecosystems. All of these pieces help students to invest in developing an evidence-based scientific explanation and engaging in argumentation about why the trout population decreased so dramatically, employing a key scientific practice as they learn core science ideas.