Reflections from examining 2018

This season I marked 140 IB DP Biology HL Paper 2 Timezone 1 papers. It was unusual for a couple of reasons: 1) I managed to pass the qualification marking on the first attempt for the first time in six years! 2) I managed to complete my marking target within seven working days and nine days before the deadline – the first time I have managed to complete the work so quickly.

I felt that this years timezone 1 exam was very straightforward to mark. This was particularly evident in the data analysis responses where the mark scheme was much easier to interpret than I recall previous years being.

Qualification

To qualify for marking, normally there are practice scripts and qualifying scripts to mark. The practice scripts are a chance for you to view comments from the senior examining team, so when undertaking these it pays to go very slowly, really thinking about how the mark scheme applies in each question and when you have marked each question, checking your own marking against the comments by toggling on the annotations. Using this method you may become quickly aware of any small details in the comments that you have missed.

In the past when I have undertaken the qualifying scripts I have opted to mark them in bulk and then submit them in bulk, so I would only submit the scripts once I had marked all of the papers. This year, instead, I submitted each script after I had marked it. This gave me the advantage of being able to read the annotations on each of the qualifying scripts, check my tolerance and adjust my marking of each of the subsequent qualifying scripts. I think this may have been a primary reason why I qualified first time.

Student misconceptions on the paper

I marked 140 scripts and when you mark that many certain themes begin to emerge. This year worryingly a large proportion of candidates were conflating the mechanisms of global warming with holes in the ozone layer. This is not a new thing and it is a problem that I have noticed in previous years but this year the sheer number of candidates writing a confused response to the question on the mechanisms of global warming was staggeringly impressive.

In 2018, 18-year-old students are still writing that carbon dioxide creates holes in the ozone layer and this is what heats up the planet – or something similar. This needs to be addressed. A teacher or teachers somewhere must be teaching kids about the ozone layer.

Now I struggle to believe that this is the result of their biology teachers (who most likely will have studied this subject to sime depth and understand the science) and I am wondering if this is the result of colleagues in other subjects unrelated to science. We know that there is a lot of confusion about climate change in the media and that the scienitific debate is often misconstrued in the popular press. We also know that this is an issue of global importance and for that reason, other subject teachers may well address it. IB student could meet it in TOK, studies in language as well as geography and other teachers. I am wondering if there are some miseducated teachers out there who are confused on the issues of climate science and are confusing their kids. This would be a great area for practitioner research and opens up the question about the professional responsibilities of teachers who have a particular subject specialism: should teachers who are well educated on a particular topic be responsible for sharing that knowledge with colleagues who may also approach this topic in the own teaching?

(on a side note a colleague previously told me that XX and XY chromosomes were “a lie” in a discussion on LGBTQ+ issues in school).

Other misconceptions that became apparent were:

  • Candidates thought that water was an organic molecule
  • Candidates didn’t understand that DNA transcription/translation = protein synthesis = gene expression = expression in the phenotype.
  • Not understanding that linked loci are genes on the same chromosome not in the same place.

Common factual errors were:

  • Few candidates knew that glutamic acid is replaced by valine.

What I learned about teaching biology this year 17-18

In 2016 I wrote this blog post. My answer to that question is now decidedly, yes. Content is King.

In this post, I want to explore why this is the case and outline what my ideas are now in relation to teaching biology.

The importance of content?

First, I should point out that a re-reading of my 2016 article makes me realise that I never concluded by suggesting content wasn’t king. Like all good questions, the article title helps to stimulate thought and a discussion about where we are at in our beliefs and in defending those beliefs. Really, the argument I was making was that teaching is not all about teaching content, but about teaching content AND encouraging critical thought with that content matter.

Content underpins everything. It underpins thinking. You can’t think without something to think about. It underpins understanding. You can’t understand something that is not represented as a propositional claim at a basic level. You can’t develop “skills” that aren’t grounded in some form of understanding.

When I am talking about content, I am referring to facts or propositional knowledge, statements that are thought to be true and are about the way the biological world is.

Propositional knowledge then must have primacy in teaching biology. To my mind, currently, propositional knowledge can be broken up into facts and concepts. Facts cannot be understood, they can only be known. Whereas concepts can be known and understood.

I think that to achieve deep, flexible, biological knowledge (flexible in the sense that it can be thought about in the abstract and applied in new situations) students need to achieve a conceptual understanding of the major themes in biology.

To do this they must first meet domain-specific examples. From those examples, they can then begin to pull out the commonalities to allow the mind to achieve an understanding of an abstract concept. My post here outlines how I went about this when teaching natural selection this year.

Learning domain-specific facts cumulatively builds to domain-specific conceptual understanding which accumulates in the learner being able to think in terms of these concepts and apply them elsewhere.

The importance of presenting content in the “right” sequence

Related to the idea of sequencing teaching so that we build up to conceptual understanding from specific examples, is the idea that we need to sequence teaching to avoid cognitive overload. To do this we need to think about which areas of the curriculum provide just enough challenge to engage students but not so much so they are overwhelmed.

In teaching biology, I think this is best achieved by teaching those areas with the least new propositional knowledge for the learner. Once the learner achieves mastery of this new knowledge then we can begin to add more.

In this sense, when trying to teach the understanding of the relationship of structure and function we may wish to look at studying the function first of any new example, before looking at the structures that support that function. Developing knowledge of the function of something might contain less instances of “facts” than the discrete structures that build up that function.

Once we have looked at lots of examples of, say, the relationship between surface area and diffusion, students will build up to the understanding of the relationship generally, and hopefully be able to apply this in new and novel ways.

Retrieval practice embedding content for the long-term

Drill and kill, right? Apparently not. My reading this year has convinced me that giving students the chance to practice retrieving information, not only builds their confidence that they can perform, and therefore reduces stress but also improves their ability to retrieve that information and therefore improves its storage in long term memory.

The same goes for learning the language of the subject and so now I try to begin my lessons with a fun low stakes retrieval practice activity. Low stakes in the sense that I do not record results and store them; students are not graded. For this I have prepared a deck of quizlet terms for the DP biology course and I alternate between using these or simply giving students a series of MCQ’s from last lesson, last week, last month and last term.

Interleaving & spaced practice – what might this look like in biology?

A year ago, on the Facebook AP/IB Biology teachers group, I first asked the question of what interleaving might look like in a biology course. I had been hearing a lot about interleaving during meetings and inset training from our DP Coordinator who is a Maths teacher. It seems that interleaving has been studied quite a bit in mathematics education.

When I asked the question, hardly anyone was aware of this concept amongst the biology teachers and I was stumped. I now have some ideas.

Interleaving or spaced practice is the idea that instead of learning all the content for a particular topic at once or in a set of continuous lessons, you space out the learning over time, revisiting topics over time.

In my experience, I have always taught a topic like cell structure and then moved onto the next topic, maybe membrane structure followed by membrane function – and I think that this is true of most biology courses.

In an interleaved curriculum these topics would be spaced out in time. Let’s imagine you have a 60min lesson every day with the same class, so five lessons a week. In an interleaved curriculum you may devote Mondays to cell structure, Tuesday to metabolism, Wednesday to plant physiology, Thursday to animal physiology and Friday to retrieval practice.

You would then teach the content of these units side by side over a number of weeks. It sounds a bit crazy but it has been demonstrated to improve long-term retention of learning and I am also excited by the possibility for the conceptual links you can make by teaching in this way.

 

Sequencing facts before concepts: natural selection

I have spent a fair amount of time this year reflecting on the application of cognitive science principles in my own biology teaching. There has been plenty written about concepts like interleaving and sequencing in sciences and maths but very little that I have found about how these concepts may apply in biology teaching.

Specifically, I have written up some of my thoughts on sequencing my DP biology curriculum based  on these discussions here.

Some of what I have learned suggests that solid conceptual/abstract understanding can only be developed when novice learners have embedded factual or propositional knowledge in their own mental schemas. In addition, I have tried to think about how principles from cognitive load theory may apply in terms of biology teaching and the sequencing of content.

One example of this has been how I approached the teaching of the concept of natural selection this year for my Y12/G11 mixed SL/HL IB biology class. In the IBDP biology syllabus, this is topic 5.2 and I sequence it after 5.1 “Evidence for evolution” and before 1.5 “The origin of cells”.

I finish the evidence for evolution section by looking at the peppered moth and the changes within the populations studied by Dr Ketterwell, through this online simulation.

In the past, I have taught natural selection by going over the concept of natural selection and then looking at specific examples of it that are mentioned in the syllabus which are antibiotic resistance in bacteria and changes in the beaks of the finches of the Galapagos island of Daphne Major.

This year I sequenced the topic into three lessons (which unintentionally appear to have been interleaved as we are also doing the internal assessment at this point in time and one lesson a week is given over to just the HL students anyway) and taught specific examples of natural selection before finally generalising from these examples to the abstract concept of natural selection.

Lesson 1 – Antibiotic-resistant bacteria

We started with retrieval practice of previous material using a google slide presentation which contained four questions: one using material from the last lesson; another from last week; another from last month and another from the last term. I then asked the students to draw and label a prokaryotic cell. Something that they covered six months ago.

Once completed we moved on to watch some news reports about antibiotic-resistant infections and I asked students to discuss and articulate back to the class what they thought the key message of each of the videos were. These prompted discussion about the general nature of antibiotic resistant bacteria and I used questioning to continue this discussion amongst the class. We also discussed what antibiotics were and why they were used to treat bacterial infections as this was a concept we met when studying the immune system two weeks prior. I highlighted the possible area of confusion for students between the words antibiotic and antibody which I had picked up from examining the previous May session of exams, before going on to explain how bacteria have become resistant to antibiotics.

I then gave the class a past paper question to complete the topic and we reviewed the key points of this question from the mark scheme.

Lesson 2- Finch beak changes on Daphne Major

Again we started with retrieval practice in the same format as in lesson 1. We then conducted a physical simulation as outlined in this practical, where students mimic being finches and collecting food. This was followed by a discussion of the trends we found in the simulation and what this might tell us about birds collecting food in the wild.

We then moved onto exercise 3 from this page and when students had finished the video and quiz I asked them to summarise what happened to the finches in the film.

Lesson 3 – the concept of natural selection

After retrieval practice, we reviewed the definition of evolution we had covered in 5.1 “evidence for evolution” and I highlighted that natural selection was a mechanism by which evolution could occur. I then asked students to think back and name the three examples of natural selection that we had considered in the last few lessons. Once they had written their answers down, I went through those examples and placed them on the board. I then asked students to discuss in pairs the details of each of these examples, before snowballing into a class discussion of the details of each of the three examples: peppered moths, antibiotic-resistant bacteria and changes in finch beaks. While we discussed these I wrote down the key points from each one on a second board with each example in a column so that similar elements from each example ended up in the same row. I then discussed with the students what these key features of each of the examples were and related this to the concept of natural selection. We finished with an example question asking students to describe the process of natural selection using examples.

Biology EAL Resources

General Bio EAL teaching resources

Quizlet deck of 100+ suffixes and prefixes

Suffixes and Prefix list supplied from comments in this post

Suffixes and Prefix list supplied by Gretel vB

IBDP Bio Reources

 

 

This much I know about EAL teaching

In my view, biology is a subject that is largely about language instruction. Of course, this doesn’t mean, to the exclusion of all other considerations. Yes, of course, there are facts and concepts that need to be learned and understood but, at its heart, it is a subject concerned with language acquisition.

And just like French, it is full of irregular verbs.

Personally, I remember the challenge of all the new vocabulary of the subject at A level, as being something that attracted me to it; I had the impression that by learning all these new words I would be entering another higher plane of existence.

So just imagine what this vocabulary is like for a new student, stepping into this level of biology and operating in their second or third language and perhaps with a very limited exposure to schooling in English. I am always surprised by the number of other adults, parents and administrators, who don’t seem to see this.

Parents, particularly, seem surprised when I bring up the issues of academic language acquisition

I have had some amount of experience teaching students who have started the subject with no English or very little English and this post will outline what I understand about teaching them today I fully recognise that  I am no expert.

James Cummins: BICS & CALP

My first foray into the realm of EAL teaching brought the work of James Cummins to my attention. To summarise, Cummins’ work postulates differences between basic interpersonal communication skills (BICS) and cognitive academic language proficiency (CALP).

Essentially, the former can be developed over a relatively short period of time (1-3 years) and is the language of peer culture. Children who have developed BICS may well sound fluent and indeed can communicate on a level using common everyday terms and phrases with their family and peers. The latter can take much longer, 5-7 years, and once developed allows the individual to think, manipulate and utilise complex academic concepts mentally. They can think with the language and they can think in very abstract terms.

It seems to me that the work of Cummins suggests that schools should resist simply placing older EAL students into secondary subject-specific classes and hoping that they will catch up. This may work with students going into grade 6 and 7 classrooms but could actually retard students progress in grades 9 and up.

Obviously, in the international context, students may well keep joining older classes (I once had a student who joined grade 10 directly from school in Israel. She has never been taught in English and yet was expected to just catch up in grade 10 biology) and so we can’t reasonably say don’t come to school. But the approach of some managers seems to be that students will just pick up the language.

These students need intensive English instruction first (if that is the language of instruction of their academic subjects) using methods that have been shown to have the largest effect size. Strategies in this category have the best hope of bringing the students learning forward faster and thus the best hope of bringing the time for students to acquire CALP down.

Isabel Beck: Tiered Model of Vocabulary Aquisition

More recently I have come across the work of Isabel Beck whose model of vocabulary acquisition places words into three categories:

 

  • Tier 1: These are the common, everyday words that most children enter school knowing already. Since we don’t need to teach these, this is a tier without tears!

  • Tier 2: This tier consists of words that are used across the content areas and are important for students to know and understand. Included here are process words like analyze and evaluate that students will run into on many standardized tests and that are also used at the university level, in many careers, and in everyday life. We really want to get these words into students’ long-term memory.

  • Tier 3: This tier consists of content-specific vocabulary—the words that are often defined in textbooks or glossaries. These words are important for imparting ideas during lessons and helping to build students’ background knowledge.

 

In biology instruction, it is the tier 3 words that all students are going to struggle with initially, but EAL students may also be lacking a good number of tier 2 words, which will make their comprehension the tier 3 words that much limited as these words often provide the context for the tier 3 words.

For example this year I can think of the words “coolant” and “yield” that came up as not being known by my grade 11 students. Many of these are students raised in English speaking families but have been attending Swiss public schools up until the start of grade 10 or 11. These aren’t words that come up in everyday conversation but are used across academic domains.

I am relatively new to the idea of Tiered vocabulary but it does seem, on first impressions, a useful way to think about words that EAL students may or may not have and to plan to help students bridge that gap.

Perhaps, one wider school aim could be to map out the tier 2 words that are common across subjects. Once a working list is compiled then students can be assessed for their knowledge of these words and interventions put in place.

Strategies

  • Identify and pre-teach complex vocab (tier 3 words) before starting the unit (I use Quizlet “learn” for this)
  • Get to know your suffixes and prefixes so that you can explicitly model your understanding of the terminology to students.
  • Keep new words on the board, clearly visible to students to use in their thinking, speaking and writing.
  • Encourage more reading and writing in your classroom. Encourage students to constantly use the new terms that they are being exposed to.
  • Use a reading age analysis to examine the tests and exams that students in your class are likely to sit – what is the level? What is the English reading level of your EAL students?
  • At the start of the course give students lots of opportunity for guided reading, ask students to identify words that they don’t know and keep a running list. Provide explanations for these words.
  • In line with the above, continue to identify Tier 2 word gaps in your student’s knowledge through reading exercises.
  • Perhaps try to list out common tier 2 words in your subject (this would take time) and compare with other departments. Check students understanding for these.