Summary
This lesson focused on the understanding of alternation of generations in plants, and began by examining non-vascular plants, including mosses and liverworts. It is intended for a botany or a phylogenic science class, and is not intended for introductory biology classes.
Essential Question(s)
How does the relationship between organisms create generational change?
Snapshot
Engage
Teacher takes students outside to gather mosses and liverworts from a nearby source, such as the school campus.
Explore
Students will observe the samples in a lab setting.
Explain
The students will watch an animation over the life cycle of mosses and learn the academic language.
Extend
Students will examine slides of mosses in specific life stages.
Evaluate
Students will write a word splash using the vocabulary words.
Materials
outdoor supply of mosses and liverworts
collection tools (plastic spoons/knives) and collection dish/plate/box (pencil box or ziplock sandwich bag works)
microscopes, dissecting scopes, and hand lenses
glass slides
cover slips
water
pipette
prepared slides of moss and liverwort life stages
pre-lab/moss stations/lab sheets/instructions
Smartboard or other projector
Engage
Teachers will take students outside to collect moss and liverwort samples. Some sort of tool (plastic knife, spoon) is used to collect the plants and the soil to which they are attached, in order to keep the plant intact. Teacher should point out the conditions favorable to moss and liverwort growth (the dark, moist areas). Hornworts could also be collected, if there are any available. Assign groups of two so that one person is collecting a moss or liverwort sample, while the other person holds the plate, watch glass, or other collection device. At this time, many students may attempt to collect other types of plants, and this serves as an opportunity to identify misconceptions. Once back at the lab, the students investigate the properties of nonvascular plants.
Explore
In the lab, students will use tools in order to investigate the characteristics of the nonvascular plants. Either pass out an I Notice/I Wonder worksheet, or have students draw a two-column table in their notes. As the students observe their collected specimens, have them document their observations and wonderings. Students should hopefully have access to dissecting scopes and/or hand lenses to view in greater magnification the gametophytes and sporophytes. Also, let students have access to rulers or any other lab supply they think they need to complete their observations. At some point, either encourage or answer the question (if it comes up) that drawings are very beneficial, and should be included in their observations.
Explain
Show the link to the moss alternation of generation. The animation shows the phases of gametophytes and sporophytes, and the alternation of generations in nonvascular plants. Then, pass out the lab handout. There is extensive background information on the handout, so have students do a Stop and Jot as they read through the background information. Instruct the students to read each paragraph at a time, then jot down thoughts and main ideas for each paragraph before moving on to the next one.
Extend
One of the attachments is the lab handout, each student should get one. Using the drawing from the Explain portion, have students answer the pre-lab questions (this can be done as homework, if that fits the classroom climate more). When they think they've finished those, have the groups start walking from station to station, observing the slides in the microscopes.
What should be included at each station is in the attachments, and the set up of the stations should be completed before the students show up, so they can get right into the lab.
Evaluate
Post the following words on the board:
Gametophyte
Sporophytes
Meiosis
Mitosis
Alternation of Generations
Gametes
Haploid
Diploid
Have students construct a Word Splash, where they construct a paragraph using all eight words in the correct context. If time allows, have some students share their responses aloud. Have students turn in their paragraph as an exit ticket as they leave.
Resources
Animation: http://www.sumanasinc.com/webcontent/animations/content/moss.html
Example of liverworts for sale: http://www.carolina.com/catalog/detail.jsp?prodId=156500&s_cid=ppc_products&gclid=CjwKEAjwltC9BRDRvMfD2N66nlISJACq8591DhjehS5wQUvK4L4UlwZLrCAXlrFD_ZG4gjB-LTnz1BoCRmfw_wcB
I Notice/I Wonder (Explore): https://learn.k20center.ou.edu/strategy/d9908066f654727934df7bf4f507d1a7
Moss microscope slides (Extend): http://www.carolina.com/plant-microscope-slides/beginners-moss-life-cycle-microscope-slide-set/292434.pr?question=moss+microscope+slide
Stop and Jot (Explain): https://learn.k20center.ou.edu/strategy/d9908066f654727934df7bf4f5077921
Word Splash (Evaluate): https://learn.k20center.ou.edu/strategy/fe96d3de46cfdc1f385aab7e7500a888