Collaborative Timeline on the Evolution of Life on Earth

timeline

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:

  1. When is this event occurring (provide the best estimates of time period)?
  2. Describe the event that you are researching. Outline key features of the event. Provide references for your research.
  3. What evidence (such as fossils where possible) do scientists use to describe this event? Include images/video.
  4. 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.

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Modelling the Inheritance of Linked and Unlinked Genes

To model the difference between linked and unlinked genes I used an activity I created that you should view here.

How it works:

By keeping some “alleles” linked and some “unlinked” we observe a difference in the inheritance pattern.

My initial instructions for this worksheet weren’t very clear but I think they are much better now. Ideally it will be printed so that the maternal genes are printed in one colour (let’s say pink, even though it’s a socially constructed convention. Let’s talk about that another time) and the paternal genes are a different colour. If I were to teach this again I would create a class set of laminated linked genes and laminated unlinked genes. The students spent far too long cutting them out themselves and I don’t think the actual process of cutting them adds anything to the learning experience.

Why is linkage important? The linkage of genes has huge implications for the inheritance of alleles. Genes which are on the same chromosome do not randomly segregated in meiosis. They physically cannot because they are on the same chromosome and so are inherited together.

Oh if only biology were so simple. NOT. That would be boooooooring! Evolution is way more sophisticated than that.

In fact, we have a process called crossing over that swaps a little bit of DNA between homologous chromosomes so your maternal and paternal DNA can be rearranged into each of your gametes. So if you can imagine, genes which are closer together are more likely to stay together. It would be very unlikely for a crossing over event to happen right at the exact spot where one gene ends and the other starts and so genes which are closer together tend to stay together.

Difficulties in defining Health and Disease

This is quite a controversial and murky topic when it comes to science (which is something scientists are not always comfortable with let me assure you!). This is because, as you will see for yourself, it is really difficult to define health and disease. I tried to come up with a list of different conditions that might be difficult to classify as “healthy” or “not healthy” if we are to use the World Health Organization definition of health. That is a “complete state of physical, mental and social wellbeing and not merely the absence of disease or infirmity”.

Complete the poll to see what you think. Also, I’d love to make this list even longer, comment with suggestions as to other conditions, which may be difficult to classify. This form of assessment for learning allowed my students to engage critically with the syllabus requirements and is an integral part of my teaching practice (Quality teaching in NSW Public Schools, 2003). Scroll to the bottom if you want to download the lesson in Word format.

Difficulties in Defining Heath Word Document

Quality teaching in NSW public schools. (2003). Retrieved from https://www.det.nsw.edu.au/proflearn/docs/pdf/qt_EPSColor.pdf