Population Explosion (Yeast Lab) (Day #2 of 3)

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Students will plan and conduct a laboratory investigation that tests the effect of an abiotic or biotic factor on the size of a population of yeast cells.

Big Idea

Populations are able to produce populations of infinite size, but the environment (and its resources) is finite.

Learner Goals

Note: I recommend that you first check out this resource in order to get the most out of this lesson!

In high school I took several drafting classes and, for a while, I had hoped to become an architect. With respect to planning instruction and teaching, I feel that I can still live out the detailed approach to building something intricate and complex even though the product is a lesson rather than a certain "built environment."

This lesson-planning template is a comprehensive overview of how I approach lesson planning. It includes the "Big Three" aspects of the NGSS standards: Disciplinary Core Ideas, Crosscutting Concepts, and Science Practices. Of course, there are many other worthy learning goals, skills, instructional strategies, and assessments that can be integrated into a class session. I don't feel compelled to check every box but, rather, use it as a guide to consider various options and tailor the lesson in light of these.

With regard to this particular lesson, students will investigate the effect of a chosen environmental factor (e.g. temperature, percent glucose solution, etc.) on the population size of yeast. In doing so, students will begin to understand the relationship between organisms and their environment and ways to create a simple model of a complex system and devise a method for measuring population changes therein.

I hope you get some value from my work!

Anticipatory Set ("Hook")

5 minutes

 This begins the second of three days of lab investigation. As such, I generally allow for a few minutes at the start of class to entertain questions that students might have about the lab procedure, the background concepts of the lab that they may still not understand, or a quick survey of each team to determine their chosen manipulated (independent) variable and the reason(s) that they chose it. Then, its off to count bubbles!

Instructional Input/Student Activities

40 minutes

Teacher note: Use this PPT as a guideline to lead students through these phases of the lab: background context, experimental design, and execution. As you discuss each slide of the PPT, have the students complete their lab handout.

1. DAY #2 Activities: This class period is designated as a set-up day with student teams implementing the plan that was made (and approved by the instructor) the previous day. The activities in this class period are very fluid. I will not let student teams proceed to the set-up phase until I have checked their entire design (see Lab Writeup Guidelines and student template).

It is quite common for student teams to have to revise some aspect (whether minor or major) before they proceed to setting up the experiment. This achieves three things:

1) It alerts them that I have exacting standards that are clearly outlined in the support document and they must follow those guidelines

2) it helps me to identify common areas of misunderstanding and, where appropriate, I can use this information to re-teach content or process details to the class as a whole

3) it reinforces that revision of student work (based on specific feedback that is linked to given standards) is a hallmark feature of the spirit my class and learning in general

Closure: What did we learn? Where do we go from here?

10 minutes

Now that the implementation of the lab is underway I use this closing segment to ensure several things:

1. Labels have been properly applied to all test tubes with the following information: lab team number, period number, the variable that is being tested (AKA MV) and date.

2. Have all lab supplies and student work areas been put away and properly cleaned? It is important to reinforce that as citizens of the learning community, all members have a duty to take care of their responsibilities. Their mother does not live in my class nor is it her duty anyway! ;)