6.5 Neurons and synapses

Cooperation and collaboration between groups of scientists—biologists are contributing to research into memory and learning. (4.3)

As we learn in TOK, the image of the lone scientist coming up with brilliant, individual insights is generally false; science is a discipline where collaboration and cooperation are critical to developing new scientific knowledge. This is particularly true today, as disciplines become ever more specialised.

There are innumerable examples of this taking place in memory studies, as the interaction between neurons, the brain and other aspects of physiology and biochemistry mean that researchers from many different disciplines are needed.

One recent example is a study investigating the role of hormones (specifically estrogen) on learning and cognition (Phan et al.).  Adding the hormone to female mouse brains seemed to boost short-term learning; the team concluded that it helps induce the formation of immature synapses (which occurs during development) and that this provides the foundation for developing and then storing new memories.

A look at the author affiliations shows the importance of collaboration:

• Department of Psychology, University of Guelph, ON, Canada
• Neuroscience Program, University of Guelph, Guelph, ON, Canada
• Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
• Laboratory of Neurobiology and Behavior, The Rockefeller University, New York, NY 10065

Such examples can be found with any search of the current scientific literature, highlighting that scientists must work together not just in studies of learning and memory, but in all fields.

Source

Phan, Anna et al. “Rapid Increases In Immature Synapses Parallel Estrogen-Induced Hippocampal Learning Enhancements”. Proceedings of the National Academy of Sciences (2015): 201522150. Web. 16 Dec. 2015.

University of Guelph. “Tie between estrogen, memory explored by researchers.” ScienceDaily. ScienceDaily, 15 December 2015.

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2.6 Making Models – DNA

Topic 2.6:  Using models as representation of the real world—Crick and Watson used model making to discover the structure of DNA. (IBO, 2014)

This year, while trying to locate our ball-and-stick DNA models, we found an old cardboard-puzzle DNA kit.

Piecing together the puzzle

It proved a great (and unplanned) way to introduce the structure of DNA and have the students examine the chemical features to deduce their own answers to the structural significance of DNA.  The advantage of this kit was that it had the chemical structure painted onto the puzzle pieces and the students, much like Watson and Crick in the early 1950s, were able to experiment with no guidance from me and determine which pieces needed to fit where.   There were many “Aha” moments as different students determined out where the different chemical pieces fit best.

The finished product!

We were thus able to figure out the significance of anti-parallel strands, purine + pyramidine pairing, 3′ →5′ linkages and the sugar-phosphate backbone.  Models in action!

5.3 Classification

Cooperation and collaboration between groups of scientists—scientists use the binomial system to identify a species rather than the many different local names.

This is one of my favourite topics (as a former zoologist) and one that lends itself to a number of different activities with students. To emphasise how different languages classify organisms in very different ways, I ask the students to come up to the board and write the name “elephant” (or another readily identifiable animal) in their mother tongue.  Here’s what we come up with today:

How many ways to say elephant?

Out of 11 students in the HL class, we had 8 different mother tongues represented in the picture above: Shona, English, German, Khmer, Chinese (Mandarin), Vietnamese, Urdu and Japanese.  This provides a clear indication of the need for a uniform system of classification.  It can also be augmented by a side discussion about, to continue the trend, elephant grass, elephant seal, elephant shrew, etc.

The next part of the lesson allows us to focus on the Khmer language (a good opportunity to link to our host-country). In Khmer, the word for tiger is ខ្លា (Klah)  and the word for sun-bear is ខ្លាឃ្មំ (klah kmoom). We discuss how this intimates a very close relationship between the two species.  But how close?

Binomial classification of the tiger and the sun bear.

A binomial classification then reveals that the two animals are indeed closely related to the level of the Order, but then separate into different Families, Genus and Species.  This makes it very apparent to the students that scientists can use the binomial system to improve communication and understanding of the classification and relationships between living organisms. Thus both the Nature of Science and the required content are covered in this lesson.  An additional extension could be to name a common name in English and then have students translate it into their mother tongue.  Jellyfish is a good example, as it is nonsensical when translated into many languages (not to mention it is not a fish!)

How do other IB Biology teachers teach classification?  How do others use language to frame the lesson?  I would love to hear from you.