As the chime sounds for students to come to their 90-minute Biology I class, Lyuda Shemyakina stands at the door welcoming each student. A “hello,” “good morning,” an exchange of pleasantries or information about homework, quickly passes between teacher and student. It is the morning of September 28, 2016.
These 9th graders enter a large room half of which contains lab tables in the rear and half of which has student desks facing the front whiteboards and teacher’s desk. The front whiteboard is filled with weekly homework instructions for students, the day’s agenda, the lesson’s objective, and upcoming events.
At the beginning of this period every day are the Mountain View High School* video announcements produced and directed by students. The two anchors of the five minute program say that the day is “World Day” (the teacher says that she is wearing her T-shirt from Barcelona). Anchors describe upcoming events, meetings that day, and announcements from various students. As I scan the room, 26 students’ eyes look to the screen. In other schools, announcements come into each room via a loudspeaker and students chat, surf their laptop and tablet screens, or stare into space. Not here.
After the announcements end, Shemyakina turns to the “bell ringer,” an ice-breaker or launching activity, for the hour-and-a-half lesson. On the screen is a slide:
Look back at your model on p. 18**. What were you not sure about? What were you pretty confident about? What questions do you have?
DON’T HAVE A MODEL? DRAW IT NOW
Example: I am not sure I drew the chromosome correctly because ….
In an earlier lesson, students had been asked to draw a model showing how DNA, chromosomes, and genes are related in a cell.
Shemyakina walks around the room checking that students are looking at the models they drew or working on drawing or answering questions on the “bell ringer”slide.
Students around me are at varying stages of finishing up the exercise. Shemyakina announces end of time and moves to the agenda for the day.
Moving around the room, she uses a clicker connected to her laptop, to project a series of slides asking students to review the DNA model on p. 18, determine where their model was correct and incorrect, what editing does it need, and what new information they want to add.
She then flashes on the screen a three minute animated video on “Genes, DNA, and Chromosomes.” As the video plays, I scan the room and see that about half are taking notes as they watch. I do not see any student that appears to be off-task, looking secretly at smart phone in their laps, etc.
Sensing that the video, while catchy with its animation, may have not stuck with students, she runs it again. Many students are now taking notes. Afterwards, she directs students to speak to their partner and review the models they created with one another and answer questions on slides she showed earlier.
Teacher walks up and down aisles looking at students’ work and asking questions. She asks one student: “Where is your cell?” A quick exchange ensues. After looking at students’ work and listening to back-and-forth between partners, Shemyakina explains about the 23 pairs of chromosomes human beings have and the range of genes in each numbered chromosome. She uses example of Angelina Jolie and the gene (BRCA) for breast cancer that Jolie discovered after a genetic test and then had subsequent surgery. Teacher again distinguishes between DNA, genes, and chromosomes. She asks class if there are any questions. No student responds.
Shemyakina then moves to another task that asks students to show that they understand relationship between DNA, chromosomes, and genes. Asking the students to turn around to face two students behind them and form small groups, she gives each group the task of making up an analogy that shows links between genes, DNA, and chromosomes.
Slide appears on front screen: DNA is like……. A gene is like …… a chromosome is like …. [on the slide, is a box that gives examples of possible analogies: a book, school, USB drive, knit sweater]
I look around the room and see that all of the groups are seemingly working on creating an analogy. Except the one near me. Teacher comes by and asks members of group for ideas they have to show relationship, they volunteer suggestions—Shemyakina mentions another group’s idea that a gene is like a pair of jeans—and this nearby group settles into working on task after teacher goes to another group.
Teacher signals end of analogy task and wants the class to see what various groups came up with. She asks students to take out their tablets and laptops***and puts a slide on the front screen:
Go to socrative.com
Room code: SHEMYAKINA
Name all members
Submit your analogies
A ding sounds as each group sends in their analogy. Their analogy appears on the screen. Teacher walks around classroom to see that each group sends in their answer. She asks students to read each one and then consider which best gets at the relationship between DNA, genes, and chromosomes. She asks them to vote. After a minute, she shows the top three vote-getters.
She analyzes each of the three for strengths and flaws. For example, Shemyakina elaborates one group’s analogy to a library. The chromosome is the library; the book is the DNA; the shelf is the gene. She agrees with this comparison.
At this point, the teacher segues to an explanation of DNA strands, how long they are, and that they are twisted compactly into double helices. To get at this, Shemyakina shows a brief animated video of a cell, the nucleic zone, and how DNA strands are twisted and densely tied yet can be seen under electron microscopes. She asks students at the end of the video to edit their models, adding or subtracting information that they now have. I see some students doing that; others conferring with partners.
After about five minutes, Shemyakina shifts attention to the question: “What’s bigger—a gene or chromosome?” Students listen as she explains that the average human has 23 chromosomes; the smallest chromosome has 200 genes. Each parent contributes 23 chromosomes to a baby. One student asks question about the Y chromosome and determining sex. Another student asks similar question. Teacher points out that these are fine questions and the class will take sex determination up in a later unit.
With about 35 minutes left in the 90-minute class, Shemyakina segues to the impending lab on cell size. The next half-hour is preparing students for the central lab question: Is it better for cells to be small or big? Why?
Students assigned as “material managers” pass out orange worksheets**** that will guide the lab they will prepare for now and do in the next lesson. She asks students to work with their partner in answering the first question about the size of the cells in the largest mammal—the blue whale—and the smallest mammal, the pygmy shrew. The worksheet question not only asks for an answer but also asks student to write down their reasoning behind what they answered (see below, first page of worksheet)
Name: _________________________________Period: _______Date: _______________
Cell Size Investigation:
Is it better for cells to be small or big? Why?
Introduction, part 1
The blue whale is the largest mammal in the world. The pygmy shrew is one of the smallest mammals in the world. How does the size of average cells compare between a blue whale and a pygmy shrew?
- The average cell of a blue whale is smaller than the average cell of a pygmy shrew.
- The average cell of a blue whale is larger than the average cell of a pygmy shrew.
- The average cell of a blue whale is about the same size as the average cell of a pygmy shrew.
I think answer ____is correct. My reasoning is ___________________________________________
Introduction, part 2
In this lab, you will investigate whether big or small cells are more efficient at taking in materials and removing waste. All cells need materials, like sugar and oxygen, to function properly. Similarly, all cells produce waste, like heat, carbon dioxide, and lactic acid, that must be removed from the cell.
To visualize this, imagine running at full speed. When you run that fast, your cell start to produce lactate (also known as lactic acid), and after 10-20 seconds, you start to feel burning in your arms and legs. Lactate causes this burning. Lactic acid is a waste product that cells produce when they’re burning sugar and making energy very quickly. If cells couldn’t get rid of lactic acid, they would become too acidic to function! So, we come back to these questions: is it better for (muscle) cells to be big or small? Will a big or small cell get rid of lactic acid faster? (to read more about lactic acid and sore muscles, go to tinyurl.com/Lactate123).
I think __________________ (small or large) cells can rid of lactic acid faster. My reasoning is ______
Shemyakina circulates through classroom asking partners what their answers are about cell size in blue whale and pygmy shrew. She asks about their reasoning. She tells class that if they want to revise their answer, they should do so. After about five minutes, she directs the class to the second question on whether big and small cells are more efficient in feeding and eliminating waste. The handout has an example of a person running and building up lactic acid that causes burning in muscles. She asks partners to help one another in answering question of whether small or large muscle cells can get rid of lactic acid faster. Again the handout asks students to give their reasoning.
I look around the room and see nearly all students working with partners or shifting to small groups of four to discuss their answers and reasoning. Shemyakina goes up down aisles checking what small groups and partners are writing and discussing.
After alerting students they have a minute to finish up answer, she moves to final activity in preparing for lab that will answer the question about cell size. On each of the lab tables are small potatoes, a metric ruler, string, and thermometer (see above photo).
For next 15 minutes, Shemyakina explains how measuring the size of anything is complicated. She uses slides to show that in measuring the size of humans, you can measure top of head to toes or hand to hand with outstretched arms. She gives similar examples for weight and surface area of a person. Then she shifts to potato and says: “You must have some way of measuring the size of your big and small potatoes.”
A slide shows ways of capturing measurements through mathematical equations or written words.
She asks students to begin answering the lab question on big vs. small cells on their worksheets. A few students go to the lab tables and pick up potatoes, rulers, and string to figure out how best to measure the vegetable. Partners and small groups, as I look around the room, are engaged in the task. I do see a few of the 15 year-olds off-task for a minute or two and then re-engage with small group. Shemyakina cruises through the room asking questions of students and listening to partners as they explain what they are doing. She tells one small group that they should check pages 7 and 11 in their notebook to get help on what they are doing now.
With a few minutes left, Shemyakina asks for “eyeballs up here” and goes over what is due for their next class—turning in completed worksheet–and upcoming dates for work to be turned in.
Chime sounds to end Biology I class. I stay a few minutes longer—it is 15-minute brunch time in the schedule—to ask Shemyakina a few final questions about the lesson. I thank her for inviting me into her class.
* Part of the Mountain View-Los Altos High School District, Mountain View High School has just over 1800 students (2015) and its demography is mostly minority (in percentages, Asian 26, Latino 21, African American 2, multiracial 2, and 47 white). The percentage of students eligible for free-and-reduced price lunches (the poverty indicator) is 18 percent. Eleven percent of students are learning disabled and just over 10 percent of students are English language learners.
Academically, 94 percent of the students graduate high school and nearly all enter higher education. The school offers 35 Honors and Advanced Placement (AP) courses across the curriculum. Of those students taking AP courses, 84 percent have gotten 3 or higher, the benchmark for getting college credit. The school earned the distinction of California Distinguished High School in 1994 and 2003. In 200 and 2013, MVHS received a full 6-year accreditation from the Western Association of Schools and Colleges (WASC). Newsweek ranks MVHS among the top 1% of high schools nationwide. The gap in achievement between minorities and white remains large, however, and has not shrunk in recent years. The per-pupil expenditure at the high school is just under $15,000 (2014). Statistics come from here and mvhs_sarc_15_16
** The page number refers to a notebook that each student has filled with worksheets and handouts the teacher has given students for daily lessons. So “p. 18” refers to the DNA lesson (including the lab exercise) that the class is currently working on.
***Two years ago, after teacher-led- pilot programs, the district required high schools to use a Bring-Your-Own-Device (BYOD) program where students brought from home their tablets and laptops. For students who did not have a home computer or what they had broke down, the school made chromebooks available.
****According to Shemyakina, five biology teachers designed this worksheet. After meeting face-to-face, they collaborated further by using Google Docs. They did this for all parts of the unit so teachers were using the same lab and could compare what students were doing in each lab.