Biology Models: Consider the Red Blood Cell

It was a pretty good lecture, as lectures go:  brief and to the point, with interesting subject matter– the red blood cell!  All other cells in the body depend on it to bring that life-giving substance, oxygen.  It’s tough and stream-lined to perform its function–zipping through the blood vessels with its payload, bumping into the vessel walls and other blood cells, stacking into rouleaux which reduce wear and tear.  Early on it loses its nucleus and organelles, including mitochondria, so it can transport oxygen with maximum efficiency, traveling by the bulk flow of the blood.  I described its width–8 microns–and the fact that it can fold to fit through capillaries that are only 4 microns in diameter.  A lovely little cell, admirable in every way!

And the next day the class remembered nothing!  I could almost believe we were viewing each other from alternate universes, with no sound and no meaning bridging the gap in between.  Over the summer I thought about it a lot, and finally I went shopping.  In a pet store I found a flexible rubber frisbee.  The fabric store yielded some stretchy red cotton knit and some batting to pad the edges.  Then I went home and sewed a red blood cell, a handsome bi-concave disc, flexible yet strong.

In time, I added to the one red blood cell: an ABO set plus a sickle cell.

In the new school year the day finally arrived when the lesson included blood cells.  This time I tossed the disc to a kid in the middle of the room, asking “What is this?”  They passed it around, looked at it, and came up with the answer.  “Why do you think so?”  “What characteristics do you notice?”  “How can this 8-micron-wide red blood cell fit through capillaries only 4 microns in diameter?”  “What could be the benefit of having no mitochondria?”  At this point I added five minutes worth of further information.  The next class meeting, the students could tell me a lot about red blood cells, without even checking their notes.  Over time that one red blood cell grew to a collection of four, with black and white buttons to represent blood type antigens, plus an appropriately shaped sickle cell.

My conclusion:  an object to hold in the hand, to observe, to bend, and even toss around the room, made quite a positive difference in kids’ receptiveness and retention!  Probably any teacher reading this has already reached this conclusion for her/himself, and I knew this too, even before the red blood cell epiphany.  However, after that I devised even more biology models, and I used them in a more determined and systematic way.  Using them in an introductory lecture, then having students explain key concepts using them, and finally, bringing them out for review prior to tests–this is a powerful strategy to enhance student understanding and recall.

So when and how could a teacher use manipulatives?

  1.   Introduce a topic:   Bring out your biology models to lead into a lecture.
    Question the students:  What do you observe?  What do you suppose it represents?  What is its function?  Comment on the surface area-to-volume ratio– is surface area increased by the way the object is shaped?  How would that affect its function?  How might it interact with what you studied before?
  2.  In your lecture:  Manipulate the biology model yourself as you discuss it.
  3.   Pose a mystery:  Hand out the model and have students examine it to find an answer.    Ex:  How does this red blood cell, 8 microns in diameter, pass through a capillary that’s only 4 microns wide?
  4.   Have students use the object to explain its function to the class.
  5.   For a powerful review:  Put your biology models out in stations with question cards for the students to use, answering  together as they move around the room.
  6. Comply with NGSS:  NGSS calls for use of models.  When there isn’t time for students to create their own, then bring out biology models you have made or purchased, and watch your students get engaged.

 

Six Cool Ideas to Help Teach, Learn, and Review

Are you seeking active learning strategies that will engage your students?  Do you want your students to have fun with life science?  Here are six great ideas, for teachers by teachers, for using our educational tools in teaching, learning, and review!

In Combination

Put several kits on the board at the same time and let the class figure out how they’re connected.  Different kit combinations that can be useful include:

  •  Macromolecules/Digestive and Respiratory/Enzymes (see the image below)
  •  Macromolecules/Enzymes/Protein Synthesis
  •  Cells/Cell Membrane/Photosynthesis
  •  Photosynthesis/Cellular Respiration
macromolecules_digestivesystem_enzymes
Pieces from several board kits are displayed at once to challenge the students. Change the enzyme name to lipase or amylase. Ask students to match the enzyme to its substrate and location.

Repeat to Remember

Leave a kit up for awhile so the kids can just handle the pieces and put them together over and over.  Handling and assembling the kits repeatedly can help students remember structures and understand processes in biology and life science.

Review/Use Stations to Engage Students

To review for a test, set up stations with our life science kits and have the kids work their way through the stations, assembling and explaining them to each other.  They’ll be more engaged in the review if it feels less like a lecture, and as they handle the pieces they will remember what they learned initially.  And you can also use our magnetic life science models as assessment tools in teaching life science and biology.

Emergent Properties Intro

The Levels of Organization Kit makes a particularly effective tool for student discovery and engagement.  Students will have some prior knowledge on this topic, and as they attempt to place the levels in order and match them to the pictures, those who are watching will be drawn in to help arrive at the correct sequence.  This makes a powerful introduction for a lecture on emergent properties and even for an overview of your course!

Not Enough Magnet-Receptive Board Space?

Improve your classroom setup with more board space!  Drop by a paint or hardware store and pick up magnetic paint.  This is water-based paint that is full of iron filings.  Two coats on a wall or cupboard doors will provide extra display space.  The paint can be given a top coat in a color of your choice.

The Coolest Idea of All!

Speak Easies kits save you time by helping to organize your lecture, by providing a quick review of your topic in the background information sheets (Board Kits), with suggestions for use, and with built-in activities in the Desk Kits.  Wouldn’t you like a little spare time?

 

 

Place-Based Learning: Restore a Watershed!

STRAW Student Restoring a Wetland
A smiling student hauls mulch for newly planted trees in a wetland restoration.   Photo courtesy of STRAW

When you’re looking for project-based learning that is rich and rewarding, having your class restore a creek or wetland can’t be beat!  Kids are out of doors, learning by doing, and benefiting their community and the environment.  Fresh air, physical exercise and teamwork make a powerful combination.  Plus at-risk students sometimes come alive at a restoration, experiencing the benefits of teamwork and performing real work that helps the environment.  Sometimes the unexpected happens:  the kids find a snake or lizard, tracks of a raccoon or even mountain lion scat!  One team dug up the champion of all root balls from an invasive Himalayan blackberry.  And once, working on a creek at a ranch,  the class was super excited as a calf was born in front of their eyes!

Elementary school students working together to restore a wetland
Students restoring a wetland–teams spread out to get the job done. Photo courtesy of STRAW

Many topics related to watersheds, creeks, and wetlands can be explored in the classroom, either before or after the restoration takes place.  You’ll find some suggestions at the end of this article.

But how do you get your class involved with a restoration of a creek or wetland?  Read on.

Of course, you can plan and carry out a restoration all on your own, though it’s a lot of work, and the expense for plants, tools, watering arrangements, etc. will certainly add up.  But here’s the valuable bit of information you should know:  there are many watershed groups around the country doing this kind of work.  Friends of the ___ River, Friends of the ___Bay, as well as other environmental NGO’s, local water agencies, and local departments of public works, may have restoration projects in the works or may be able to connect you with other groups that are involved.  And that could save you an enormous amount of work (and money), but still have your students restore a creek or wetland.

For the ten years since I retired from teaching biology,  I’ve worked with a watershed group north of San Francisco Bay called STRAW, Students and Teachers Restoring a Watershed, a project of Point Blue Conservation Science.  My classes— biology, physical science, and environmental studies— worked with this group before I left  the classroom, so I knew what they were all about and went to work for them eagerly.  STRAW began 23 years ago and performed its 500th restoration in 2015, having coordinated restorations involving many thousands of students, K-12, and having restored over 30 miles of creek banks and acres and acres of wetlands.  STRAW also has our team of dedicated retired educators who take related lessons into the classrooms.  Having repeatedly seen students restore creeks and wetlands and the impact on students and teachers, I can’t think of a more powerful project to benefit everyone!

So what kinds of classroom lessons make a smooth fit with restoration and have rich educational value?  Here are just a few:  water quality and testing, native plants and animals, food webs and energy flow, rain gardens, water-borne disease, population studies and estimating numbers, identification and classification, carbon sequestration, and sustainable water policy.  Plus another big one: positive ways of dealing with climate change!  Read about climate smart restoration here.

And here you can read one teacher’s comments after she had her students restore a creek with STRAW.  

Creek Restoration: Tony Plants a Tree!

deskWe know that place-based learning can make a positive difference in kids’ lives.  For example, restoring creeks can restore kids.  At-risk kids, kids with gang affiliations, kids with low self-esteem:  all of these can benefit from accomplishing the restoration of a creek.  But sometimes it doesn’t lead to a complete turnaround…

There he was—the kid who was placed in my sheltered biology class to wait out the two weeks till he could be transferred to the continuation high school. Well-groomed and fastidious, doused with aftershave, he walked in and put his head down on the desk as soon as he was assigned a seat. And there his head remained day after day. He was absolutely determined not to do a thing. The day arrived when the class went to the creek bordering the school to work on a restoration, removing some invasive plants and planting native trees, shrubs and forbs. “Tony” asked to stay in the classroom, but I refused— after all, no one else would stay behind. So he came along as we walked down to the creek. Proper planting techniques were demonstrated and tools were distributed. The work began. I brought Tony a shovel and led him to a spot that needed a tree. He balked, I insisted. His clothes would get dirty, but “Not to worry—it’s not muddy.” His hands would blister and get dirty; “You’re in luck, Pal—here’s some work gloves.” And finally Tony went to work. The class was there for an hour and a half, and Tony planted three trees, with a little help from a couple of classmates. As we walked back to class he had a little swagger in his step and was more animated than I had ever seen him.

I wish I could report that Tony turned the corner that day, but no. He kept his head on the desk the few remaining days till he transferred out. Still, he planted three trees, trees that are growing there even now. And I don’t know what that might have meant to Tony. Maybe the experience had some positive value for him. It certainly had positive value for the creek!

And it had a lot of value for the rest of the class. The students were proud of their work and supportive of their team members. They made a positive difference for the environment, their school, and their community. More to come about restoration in our next posting.

Waterborne Disease/ Poop Chronicles, Part Two

Waterborne Disease/ Poop Chronicles, Part Two

 

stopepidemicscreenshotThe cholera epidemic in London in 1854 was raging on, and Queen Victoria had called Dr. John Snow and commanded him to stop the epidemic.  But this seemed impossible, since no one at the time understood the germ theory of disease or how diseases spread.

Some strange ideas about how to avoid disease were floating around, as seen in this somewhat exaggerated newspaper cartoon.  We can all imagine how scary it must have been to be surrounded by an epidemic and not know how to protect yourself.screenshotstayinghealthy

But Dr. Snow did something unprecedented—he went into the area of the city where the epidemic was in progress, the neighborhoods around Broad Street, and he interviewed the survivors of the disease as well as the families of the deceased, to gather information about how the victims had lived, looking for clues.  [The students can be supplied with this map of London at the time.  Discuss with them the symbols on the map, being certain to discuss the pumps that were in use.  The picture at the end of this article may be helpful, since not many students have ever used such a pump, but if you show it before the class tries to figure out how to stop the epidemic, it’s a tip-off.]

screenshotbroadstreet

[At this point, the class can be supplied with information about the victims, in addition to the map, and asked to figure out how to stop the epidemic.  This activity is from Project Wet, a wonderful resource for many water-related lessons, and can be found at http://www.rivanna-stormwater.org/bacteria.pdf.  When students have figured out how to stop the disease and have discussed the additional question at the Rivanna Stormwater site, continue with the Poop Chronicles lecture.]

After figuring out that the disease was spread through the contaminated well water in the Broad Street pump, Dr. Snow told the authorities how to stop the epidemic:  “Remove the pump handle.”  Eventually the suggestion was carried out and the epidemic stopped.  It was found that “Patient 0”, the source of the disease, lived in a tenement house close to the Broad Street pump, and effluent from the tenement’s privy was leaking into the ground water and contaminating it.

Subsequently the Queen called in Sir Edwin Chadwick, who made some recommendations to improve the health of the people living in London.  He designed a house, intended for a single family to live in, which removed their pump at the greatest possible distance from their privy and also supplied more room as well as air circulation and natural light.

screenshotlondonsewersAnd eventually this plan was submitted to the Queen.  What does it show?  Sewer lines!  Even  so, when the sewers were put in, they simply drained the sewage to the river.  Sewage treatment plants did not come about till later.

 

screenshotwaterpump

[A good extension of this activity would be to investigate some other waterborne diseases (for example, polio virus, giardia, Salmonella typhus),  along with a few other contagious diseases.  Students could be given pictures of the pathogens that cause the diseases and asked to investigate the symptoms, causes and cures, in addition to prevention.  The students could also be given a picture of the body showing different organs and asked to match the pathogens to the organs they infect.  And finally, they could sort the pathogens according to which taxonomic kingdom each belongs to.

To emphasize the environmental aspects of waterborne disease, you might show students the form below, which shows a data table for a number of tests that, taken together, comprise a water quality index.  Note that one of the tests checks for the presence of coliform bacteria, a family of bacteria always found in sewage.]screenshotWQI

 

 

 

Waterborne Disease/Poop Chronicles, Part One

Students are interested in disease, especially the diseases with a high yuck factor! Waterborne diseases fill the bill. Plus, this subject encompasses lots of important topics: sanitation, hygiene, the digestive system, water treatment, microbiology, etc. You can even look at history and warfare from a perspective of disease. So here are some pictures and a mini-lecture to get started.  (I also mentioned one or two diseases that are not waterborne, just because their mode of transmission is interesting!)

In ancient history, before settlements were established, the world’s human population lived in small tribal groups that were nomadic. They hunted and gathered in one area till game ran low, then they moved on. And as they moved they left their wastes behind. A good idea, since human wastes can harbor disease!

But about 10,000 years ago people started planting seeds and domesticating livestock. This was a huge change that we call the first agricultural revolution, and it allowed humans to settle in one place.  In time farmers became successful enough that they had excess grain that could be stored, encouraging the presence of rodents, which in turn carried diseases such as smallpox that could then make the jump into humans.

poop chron screen shot ag with irrigationpoop chron screen shot mice

Isolated settlements sprang up, and they were usually located on a river or stream so people had plenty of water for drinking and for irrigation.  And rivers were also used as handy places to dispose of wastes.

Over time the settlements grew into teeming cities and wastes built up, harboring microbes that caused outbreaks of epidemics.  Merchants went from marketplace to marketplace, bringing diseases with them.

As the human population grew, settlements sprang up in the empty spaces between cities.  At the point in time when settlements began to be located about two weeks’ walk apart. Smallpox:  incubation period of fourteen days⇒epidemics!

Next:  a phenomenal change occurred in human history:   the Industrial Revolution.  Threshing machines and other inventions could do the farm work and the out-of-work farm workers moved into the cities, to become laborers in factories.

poop chron screen shot working conditions

Working conditions there were often miserable:  long hours (dawn to dark), dusty, dark factories that were unsafe and closed in, no vacation, no sick-leave.  Child labor was common, even in mines.

Living conditions for the poor were crowded and unhealthy, with several families living in one room of a tenement building.  The air of the cities was dark with smoke and soot and the streets were filled with trash and garbage.  Slaughter houses with blood, dung and flies were built in the cities, sometimes located next to schools.  Rivers carried chemicals and raw sewage floating on the surface.  Drinking water was accessed in public wells and was also taken directly from the river, bottled and sold untreated.

As shown in this fantastical newspaper cartoon of the 1800’s, people were starting to be disgusted by the appearance of the water, though they didn’t connect disease to the organisms that they could see in it with their microscopes (then popular as curiosities).

poop chron screen shot shocking water

Outdoor privies were used for human wastes which collected in storage holes called cesspools, which were sometimes lined with brick or stone, but were sometimes just bare dirt.

It is estimated that by the 1850’s the city of London had 20,000 outdoor privies.  In the home, for convenience, people used chamber pots.  In the mornings, housewives tidied up by emptying the contents out the windows of the upper stories.  Look out below!

poop chron screen shot priviespoop chron screen shot chamber pots

These were the conditions when a cholera epidemic swept through the city of London in 1854.  Cholera was, and still is, a fearsome disease.  A victim can be healthy in the morning and dead by noon!  It is characterized by nausea and vomiting, cramps, and severe diarrhea.  Cholera sometimes breaks out, even today, where people are crowded together in conditions such as are found in many refugee camps, after a war or severe flooding or other natural disasters.  Medical workers in these places often put the patients on cots such as the ones pictured, with buckets under the holes to facilitate clean-up of the diarrhea.  So much fluid is lost from the body that vital minerals, needed for the heart to function, are carried away with the fluid, and the victims die of heart failure.  In recent years it has been discovered that clean water mixed with a little sugar and table salt, given by mouth or intravenously, can spell the difference between life and death!

poop chron screen shot cholera cots

This brings us to London and the cholera epidemic of 1854.  In one area of the city hundreds of people were infected and as many as 50% of the patients died.  Queen Victoria summoned Dr. John Snow,  a famous person in epidemiology even now, and directed that he stop the epidemic.  This was a tall order since the cause of cholera and the means of transmission weren’t known then.  In fact there was little understanding of diseases and germs at that time.poop chron screen shot the queen

See The Poop Chronicles, Part Two,  for the rest of the story, and for a fascinating activity modeling London’s cholera epidemic and asking students to figure  out how to stop its spread.

 

 

No infringement of  copyright is intended with the use of these pictures.  Owners of copyrights can request removal and we will comply promptly.

 

Exciting Cell Projects for Your Students

Cells and Cell Projects
To introduce the cell or for review, you can’t beat manipulatives! Pictures of organelles that can be placed on a picture of an “empty” cell, (just the membrane or membrane and cell wall with cytoplasm and maybe ribosomes) can be a very effective strategy to engage students.
Have students try these:

  • Assemble and compare the plant cell and the animal cell.
  • Pass out the organelles.  Call out the name of an organelle and have the student who holds it bring it to the board and explain its function before adding it to the cell.
  • Have students choose the relevant organelles and use them to explain and enact an overview of protein synthesis.

Cell Projects                                                                                                                                                             Cell models made of cake, cookies, Jello, legos, styrofoam, cardboard, cloth.     One student, a dedicated skater, even made his model using bits of hardware from an old skateboard, housed inside a small metal box that originally held skateboard bearings!  The key to the organelles was pasted inside the lid.  I ran into him in a cafe 15 years later, and he told me he still remembered that model!
So it seems that these projects are time well spent. But after retiring, I wondered. If the high school students have made cell models in middle school and a brief review is sufficient to bring it all back, or if you want to present your class with more of a challenge, then maybe it’s time to up the ante.
How about going beyond the generic cell model and asking /assigning students to create a model of a specific kind of cell? Many cells are fascinating in their own right. With around 200 cell types in the human body, there’s such a rich assortment to choose from! But some students might prefer some type of plant cell or even a single-celled organism. You’ll see some ideas on the next page.

Cell Project—High School Level                                                                                                                        Make a choice from the lists below for research and a presentation. Make a poster to help as you present. Differentiated Cells These cells are specialized cell types that perform special functions. General requirements and questions to consider: Compare and contrast the specific cell(s) you chose to the generic plant or animal cell studied in class. What important function does your cell perform for the organism it is part of? How does the structure of your cell relate to its function? Are any of your cell’s organelles absent or present in extremely large numbers? To what effect? How does your cell function to help maintain homeostasis? Explain. Give special attention to any interactions between cell pairs. Do the cell pairs act together to achieve balance for the organism they are part of? What might happen if the cells’ interaction gets out of balance? Do the cells help each other in some way?                                                                                                                                           Cell Choices:

  • a cardiac muscle cell
  • a striated muscle cell
  • osteocyte/osteoblast/osteoclast
  • neuron and glial cell
  • sperm cell and Sertoli cell
  • red blood cell and platelet
  • vessel element
  • sieve tube member/companion cell

Cell & Protein Choices:

  • adipose (fat) cell and leptin
  • plasma cell and antibodies
  • chief cell and pepsin
  • red blood cell and hemoglobin
  • alpha cell of the pancreas and glucagon
  • beta cell of the pancreas and insulin

In the Age of Technology, Is Touch Obsolete?

Thoughts on Hands-on Aids in Teaching

Clearly technology is marvelous! It connects us to all knowledge all the time. Push a button, and any question is answered. Every structure is pictured; every process is animated. So perhaps tactile learning and kinesthetic learning are now outmoded! But wait. Ask a child. Ask a parent. Ask a lover. Best of all, ask a teacher!

Photo: Baby exploring tree with touch
Babies arrive at birth with an already well-developed sense of touch that continues to inform their perceptions of the world throughout their lives. Above, a 4 1/2 month-old baby, touching the bark of a spruce tree.

Teachers know classrooms are still full of diverse learners. Multiple intelligences and many varied learning modalities still exist. Kids need to move, and they need to use manipulatives. They need the teaching strategies that address these diverse learning styles.   Holding an object in your hand is an intimate act, and it gives possession to the holder. It connects us to the object itself and to the concept it represents. Teachers know how vital it is!

And of course, there is brain research. Marcia Tate and Warren Phillips, writing in their excellent “Worksheets Don’t Grow Dendrites” series, list manipulatives, experiments, labs and models, as well as movement, as essential teaching strategies that address brain-based learning. Tate’s and Phillips’ books cite and quote research rationales from experts in the field. (You can watch Marcia Tate here)

Speaking of touch, many excellent manipulatives are out there. Let students handle a model of a five-pound chunk of human body fat (Life/Form), available at eNasco.com, and they won’t forget your discussion of lipid molecules! Get students at the board, assembling a lipid (triglyceride) molecule from Speak Easies’ Macromolecules Board Kit, holding the pieces and mulling over their placement and function, and the intimacy of touch will facilitate connection, understanding and retention!