Tag: lesson

Mitosis dance

Anaphase.

One way to represent the process of mitosis is through dance. One of my students suggested they do an interpretive dance for their natural world personal project. I think they were mostly kidding, but with a fair bit of encouragement they did end up doing it.

The dance is much more literal than it probably needs to be since I helped a bit with the final product. I still think it’s pretty useful though because it’s abstract enough that you have to know the mitosis process to figure out what’s going on. So much so, I had them perform it twice at the end of our synthesis discussion. The second time through I narrated it so the steps would be clear to everyone.

I think it might make for a good “spark the imagination” lesson if one was needed.

Right now the dance needs four people, two for the chromosomes and two for the centrioles, but it would be really neat if the entire class participated by representing the cell membrane.

The diagram with the steps is: mitosis.svg. The instructions are below.

Steps

  1. The DNA (DNA 1 and DNA 2) stand facing the audience with DNA 2 hidden behind DNA 1 since the DNA have not yet duplicated.
    • The centrioles (C1 and C2) just stand there with C2 pretending not to be there.
    • DNA 1 mimes touching the nucleus walls while DNA 2 pretends not to be there.
    • DNA 1 dances the DNA helix, which probably involves lots of hand motions and spinning around taking 23 steps to represent the number of chromosomes in humans.
  2. Replicating: DNA 2 steps forward while C 2 moves around the two DNA to get to the other side
  3. The DNA join hands and spin around (because it’s fun to do, apparently)
  4. The DNA line up next to each other and lock elbows while the centrioles start extending their threads, which probably involves some type of waving hand motion.
  5. The centrioles move in, with their threads, and grab the open elbows.
  6. The centrioles pull the DNA apart.
  7. The two DNA act out the reforming of their nuclear membranes.
  8. The DNA-centriole pairs wave each other goodbye as they become separate cells. (This is where having the rest of the group as the cell membrane would be nice.)
Steps to the mitosis dance.

Timeline of life

Timeline of Life on Earth.

This year the theme is life. My central organizing structure is the timeline of life on Earth. I plan to link all of the discussions of taxonomy, phylogeny and genetics to this timeline over the course of the year.

The timeline above will be the first lesson. As with these things the trick is deciding how much detail to keep in and how much to keep out.

What I like is that it gives the general overview of when important things happen while leaving a lot of space for students to investigate. Most of what we’ll be seeing this year happened in the Cambrian and this timeline conveys that this is a very small part of the whole history of life. In fact, it’s only when we cover the biochemistry of genetics that we will be talking about the origins of life.

From the Exploring Earth's Origins website.

The website Exploring Life’s Origins has a great timeline. It also has some really neat sections, with very useful videos, on the formation of protocells and the origin of RNA on the early Earth that lead to life as we know it.

The Magnetic Field?

The one thing I left out that I’m still conflicted about is the Earth’s magnetic field. Recent research indicates it has been around since 3.2 billion years ago and its presence or absence may have had profound effects on life.

The Earth's magnetic field protects us from the solar wind. Image from NASA.

Having a magnetic field protects the Earth from the charged particles spewing out of the Sun, the solar wind. This makes life on land a lot easier since the solar wind’s particles are quite damaging to DNA. However, prior to the magnetic field forming all this damage to DNA may have also accelerated mutation and thus evolution.