[Catalist] That's Dr Pond Scum to you !

[Michael Cameron]

Thanks Leon,
Your students are very fortunate!

From: Catalist <catalist-bounces at lists.stawa.net> on behalf of Leon Harris <leon at quoll.com>
Reply to: "leon at quoll.com" <leon at quoll.com>, WA Science Teachers Discussion List <catalist at lists.stawa.net>
Date: Sunday, 30 May 2021 at 5:03 pm
To: Catalist <catalist at lists.stawa.net>
Subject: Re: [Catalist] That's Dr Pond Scum to you !

Hi Mick,
general microscopy in Y8. Euglena are a known size, so field of view calculations work well with them (figure FOV and compare it to known sized object, how closely do they match, at the higher magnifications).
They are ok for organelles too - you will get flagella, chlopoplasts, nucleus ,cell membrane and vacuole. For this, I'd recommend a 2% methyl cellulose solution, you could try the pharmacy eye drops.

They have quite a bit of relevance to the Y7 classification component - Euglenoids drove the early shift from a plant/animal dichotomy in classification, in that they are green, auto- and heterotrophic, and are motile.

Then there is the engagement aspect - cute, zoomy beasties that zip around are very engaging to students.

The old Y9 abiotic factors lab with daphnia can be modified quite well with euglena - film the motion with a microscope camera or your phone down the eyepiece and measure how fast they travel at different temperatures (distance from fraction of FOV and time from number of frames).

Y11 biol revisits y9, so a more sophisticated experiment on abiotic (temperature, salinity, motion) becomes possible. If you want to throw some sampling methods in there, place some euglena under a coverslip, and measure the distribution of euglena over time in terms of distance from the edge of the coverslip. (Use a grid, because you may not have a haemocytometer). Do that one in dark and you will demonstrate that oxygen is an essential abiotic factor, even for things that photosynthesise, and that their behaviour changes measurably to deal with it.

I am not teaching biology these days, but there are plenty of opportunities with euglena.

Have fun now !
L.
On 30/05/2021 2:19 pm, Michael Cameron wrote:

Hi Leon,
Wow sounds interesting. I'm a new biology teacher and have no experience growing anything smaller than a tadpole. I live in Albany so it's not practical to meet up. But I'm just curious what are the main educational benefits for using these in upper school biology?
Mick Cameron

On 30/5/21, 2:06 pm, "Catalist on behalf of Leon Harris" <catalist-bounces at lists.stawa.net on behalf of leon at quoll.com><mailto:catalist-bounces at lists.stawa.netonbehalfofleon@quoll.com> wrote:

     Greetings Catalistians,

     I have cultured up a really great little Euglena gracillis. It is thick,
     matted and green, kind of like Shreks armpits.

     Does anybody want some? Maybe we can organise a bit of an underground
     railway to deliver.

     I am working on Daphnia magna at this time, but they aren't ready yet.


     Cheers,

     Leon

     (Dr Pond Scum)




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