I wanted to do something a bit fun with this. I thought if I made it online, I could make it a whole class collaborative project. I listed the different events in the history of life on Earth and gave my students a brief run down of what the different events were. Then asked them to create a very short summary answering the following questions:
- When is this event occurring (provide the best estimates of time period)?
- Describe the event that you are researching. Outline key features of the event. Provide references for your research.
- What evidence (such as fossils where possible) do scientists use to describe this event? Include images/video.
- How does this event contribute to the diversity in the evolution of life on Earth? I.e. what implications does this event have on future life on Earth?
I then asked my students to peer assess another groups summaries against the same above criteria and fix up any suggestions that the other group made on their own summaries. Finally this edited version was to be uploaded onto a class timeline generated on Timeglider. I’m not sure this was the best Web2.0 tool to use for this purpose. It didn’t allow collobration between members so basically we all used the same login and password to create this timeline. In future I would like to look for another tool that allows each pair of students to create an account and then they upload their work from this source. It would aid in me keeping track of who’s submitted their work and who hasn’t. My class’ timeline can be found here.
While teaching Year 12 students I noticed from their questions that many of them had not yet grasped the concept of DNA structure and organisation clearly. This was very surprising for me, mostly because (1) they were at a selective school so I naively thought that that must mean they would miraculously grasp concepts (2) we were in our 3rd term in the HSC, they should know it by now! To me, huge red flags started signalling and I approached my supervising teacher asking if she would allow me to deviate from the plan and take a lesson to revise key issues. Thankfully she agreed, although I know a little reluctantly, there is a lot of pressure to “get through” content. I couldn’t have these kids get to their final exams and not understand what a chromosome really is. After all, they were doing the core topic in biology – blueprint of life and they were also doing the genetics option. Effectively they could’ve been tested on this content twice. It was a huge gamble if I didn’t go through it.
So I prepared a series of questions aimed at pinpointing their issues. I projected these on the board and handed out laminated sheets of white paper – that I call mini-whiteboards – to each of the students and some markers and we had a quizzing and intervention session. I’d ask a question they’d respond and if it was clear that a few of them (I think I revised concepts if even 3 of them were unsure) weren’t clear we’d go through it.
From their questions it was clear that the concepts of DNA organisation was completely lost on them. They still weren’t clear on what an allele was, what a gene is and how chromosomes organise DNA or what their functions were.
It’s an abstract concept so I totally understand this confusion. If you’re teaching students about DNA, the following analogy I used might help.
All the DNA that we have in each somatic cell is a complete set called a genome. Let’s pretend this is the Encyclopaedia Britannica. You know how we have A-Z and each book has one section of the Encyclopaedia, well our DNA is organised into a similar mechanism. Each large of DNA is called a chromosome. Our chromosomes are different, just like an Encyclopaedia. The A entries are totally different form the G entries. But we need a complete set of A-Z for a complete encyclopaedia. Similarly, we need a complete set of chromosomes 1-23 for a complete genome. To add a little complexity to it, we don’t just have one set of DNA we have two. One from our mother and one from our father. So if we continue with the Encyclopaedia example this is like if we have a whole set of Britannica and another set of the World Book Encyclopaedia. We find the same entries in there, like you’ll find a definition for apple in each but they might be slightly different.
So let’s take it a step further. Each entry in the encyclopaedia is like a gene – it has a meaning and in cells that meaning is a protein. Each gene is made up of DNA in a combination of a series four bases (ATCG) these letters are what make up DNA. Similarly, definitions are made up of words.
So let’s recap.
|Broken up into books, A-Z
||Broken up into chromosomes 1-23
|Come in different brands
||Come in different alleles. We have one of each of mum’s alleles and one of dad’s.
|Each book has different entries
||Each chromosome has different genes
|Entries are made up of words
||Genes are made up of nucleotides
|Words are made up of letters
||Nucleotides are made of sugar, phosphate and bases. Each base is made of either an A, T, C or G.
What do you think? My kids loved this analogy and their relief was the most satisfying aspect of my first practicum. I want to know if you think it will work for you!
If I had a gun to my head and absolutely HAD to pick a favourite topic in biology, I would probably choose mitosis and meiosis. I can’t imagine that this would ever be the case, but you know, it paints a pretty picture. After 7 years of studying meiosis I still have to think about how to spell it – I don’t know what it is, I just find it so tricky. Anyway, mitosis. I taught this for my very first time on my first teaching practicum and the students absolutely ate it up.
Let me explain why.
So you know how when you’re really excited about something you become very animated about it and you can’t help but infect everyone with your excitement. Yeah that’s pretty much what happened. You can see the powerpoint I used to help in my presentation and you can pretty much feel the excitement leaping out at you.
stole borrowed a lot of ideas from the one and only Hank Green of the VlogBrothers. They have an amazing YouTube series called Crash Course. Here, go watch it and come back.
Oh hai there. Welcome back!
So what I basically did was tell my students (half of whom were on an excursion anyway) put your books away. This is the most exciting story you will ever be told and I don’t want you to write anything I just want you to listen. In retrospect I
probably should’ve “Checked for Understanding” but I was a novice. I might do it slightly different in future. I told them about how at a cellular level our bodies are incredible. We make over 300 billion cells per day. Just try to wrap your head around that for a second. There are 7 billion people on the planet. Gosh I love science.
So even on your laziest day where you watch 2 whole seasons of Orphan Black because your student may have told you that it’s a really good show to watch and you totally agree cause it’s about cloning. Even on those days you are freaking incredible. Then I said to them: When do we even need mitosis? What is it?
You cut your finger and your skin needs to repair itself.
You’re a newborn and you want to grow bigger and taller.
Your immune system wants to fight off disease.
Your stomach lining is eaten away by the cells they produce.
Are you noticing a pattern here? And half the class said BAM MITOSIS. It was a good moment.
Have I sold you? Wanna see my PowerPoint?