Teach.Genetics has a bunch of “Print and Go” pdf lessons on their site, but also have a really neat interactive page where you can look inside an animal cell. What’s really neat about this flash app is that you can move around a little, round window as you scan through the cell membrane. You can also take the membrane away to see everything inside the cell at once, but that takes away the challenge.
When you use the little window you have to piece together what everything inside the cell looks like by memory. For a student new to the parts of a cell this might be a bit of cognitive overload, but once your somewhat familiar with the pieces, this makes for an interesting challenge.
The Teach.Genetics site and materials are free for educational use.
Dealing with genetic traits and family trees can be kind of tricky sometimes, particularly with early adolescents who are still learning about personal boundaries and have the potential for sharing too much information. One alternative to delving too deeply into personal family histories is to stress the less invasive traits. Anna Clark has had some success (and the students liked it) using the Handy Family Tree, from the University of Utah’s Teach.Genetics website.
John Wyndham's The Crysalids. (via Powell's Books).
I also discuss some of the thornier issues when we do the John Wyndham book, The Chrysalids. It can be an uncomfortable book, but has the emotional separation of fiction.
Teach.Genetics is a great resource. They have a number of “Teach and Go” exercises like this one, and some interesting interactive applications. I’ll post more as I browse more through their website.
Boiling jam will often create a froth that floats on top, much like the granitic continental crust floats on the Earth’s mantle. Also like the boiling jam, the mantle convects (even though the mantle is not liquid).
Convection in jam.
The darker red areas in the image are where the convection cells in the boiling jam reach the surface and push the froth away. It’s a bit like the bulge in the Earth’s crust that occurs beneath hot-spots and the mid-ocean ridges.
Model of convection in the Earth's mantle (image from Wikipedia)
I’m thinking that the Creating Coacervates lab, the only one on the origin of life section, might fit into my orientation cycle plans. Coacervates are small, microscopic blobs of fat (lipids) that look like, and have many of the same properties as cells, amoebas in particular. They can be produced with simple chemicals. One of the key things I’d like to start the year with, is the idea that:
complex life-like cell-like structures can be produced naturally from simple materials with simple changes. Flammer, 1999.
These abiotic blobs can be compared to the protozoans in a water droplet sample while we learn how to use the microscopes. It also ties into the Miller–Urey experiments that produced amino acids using electricity and simple compounds: water, methane, ammonia and hydrogen gas. The Miller-Urey experiments will pop up later when we read Frankenstein.
There’s a nice article in the New York Times on the fact that oil, petroleum, did not come form dead dinosaurs, but rather from the microscopic plankton that died and fell to the ocean floor.
The idea that oil came from the terrible lizards that children love to learn about endured for many decades. The Sinclair Oil Company featured a dinosaur in its logo and in its advertisements, and outfitted its gas stations with giant replicas that bore long necks and tails. The publicity gave the term “fossil fuels” new resonance. – Broad, 2010
It’s easy to forget how pervasive is the idea that oil comes from dinosaurs. Broad’s article is a nice reminder that:
Today, a principal tenet of geology is that a vast majority of the world’s oil arose not from lumbering beasts on land but tiny organisms at sea. It holds that blizzards of microscopic life fell into the sunless depths over the ages, producing thick sediments that the planet’s inner heat eventually cooked into oil. It is estimated that 95 percent or more of global oil traces its genesis to the sea. – Broad, 2010
How do we know?
[I]n the 1930s. Alfred E. Treibs, a German chemist, discovered that oil harbored the fossil remains of chlorophyll, the compound in plants that helps convert sunlight into chemical energy. The source appeared to be the tiny plants of ancient seas. – Broad, 2010
Phytoplankton bloom off the Carolina coast. (Image from NASA).
We tend to find a lot of oil in the deltas of the great rivers because the rivers provide nutrients for the microorganisms to survive and layers of sand and clay sediments that trap the oil and natural when they’re produced.
The article also ties the location of oil production to the geography of plate tectonics.
[W]hen Africa and South America slowly pulled apart in the Cretaceous period, forming the narrow beginnings of the South Atlantic. Big rivers poured in nutrients. A biological frenzy on the western shores of the narrow ocean ended up forming the vast oil fields now being discovered and developed off Brazil in deep water. – Broad, 2010
The world is ridiculously complicated. We construct models to represent what we see and think we understand. Simple models of complex phenomena, and we’re happy when our models represent the most important patterns.
We would, of course, often like to understand the details, so we add more detail to our models. And our models get closer to reality. Yet as our models represent the world in more and more detail they themselves become more and more complex. All the simple parts of the models start to interact in increasingly unexpected ways, until it becomes almost as difficult to interpret the model as it is to understand the real world.
I’ve been thinking about science fiction, like Mirable and The Chrysalids that tie into the Natural World (science) curriculum. While I’ve not read Kim Stanley Robinson’s Mars triology, Red Mars, Blue Mars and Green Mars, they’ve won a number of awards and I’ve heard good things about them.
I’m looking for books that address global ecology, so stories about terraforming Mars would seem to fit. The Mars triology books are also supposed to be fairly rigorous and consistent about the science, something I look for in good science fiction. There are also some good articles discussing the science that can be used for supporting information, like this one by Margarita Miranova (2008) about the actual feasibility of terraforming Mars.
Feature identified by students from Evergreen Middle School. Image from NASA.
Given Mars’ proximity and the fact that space agencies have orbiting satellites and ground rovers makes the idea of colonizing Mars an intriguing one for the more adventurous adolescents. In fact, the recent news that 7th graders discovered a new feature on Mars’ surface might also inspire some interest. The 7th graders’ project was part of the Mars Student Imaging Program (MSIP), which might also be of interest. MSIP actually allows students to use the camera on board the Mars Odyssey satellite, by identifying locations for detailed images.
