The ABO+- Question

How does blood type work? Is mine common? Do I have to worry about a transfusion?

There are many different antigens, or structures, that can be present on the exterior surface of your red blood cells. They’re an important part of your immune system, and antigens generally allow your body to both recognize and respond to cells that are “other”. Not your blood? Trigger immune defenses! Dangerous non-human cells? Trigger immune defenses! 

ABO

One common set of antigens studied are A & B, carbohydrates encoded for by the A and B versions of this allele, which are co-dominant. The O allele encodes for neither of these antigens, and is a recessive trait. It takes OO to result in an O blood type. A combination of A/B and O alleles results in Type A or Type B blood, respectively. Matching A and B alleles in the same individual is the only way to have type AB blood.

+ –

Another common antigen is the Rhesus factor (named after Rhesus monkeys, where this was first discovered). This is a protein antigen, and is either present + or absent – in addition to the other antigens. Remember, these are just two of many antigens that can be present on your red blood cells, and the possibilities when you extend this concept to all cells in all species with innate immune systems is practically endless.

Hazards

When you compare blood types, this is where the transfusion/transplant question comes into play. Blood type compatibility can also be a potential problem during pregnancy. If an organism’s system is encountering blood (via medical treatment or via the placenta) that contains antigens that aren’t recognizable as belonging to you, it triggers the immune system. Organizations like the Red Cross consider type AB+ to be a universal receiver because those cells already contain (and recognize as safe) all three of the major antigens (A, B, and Rh). Type O- is considered the universal donor because it contains none of those three antigens.

For example, if a person with type A+ blood needs a transfusion because of an injury, it would be relatively easy to find a matching donor. Why? The injured person has the A and Rh antigens, so they can receive any type A blood or any type O blood, + or -, without it being rejected by their immune system.

Frequency

On the whole, O is most common, followed by A, B, and AB. For the Rh factor, + is more common than – is. Combined, this means that most people have only the Rh antigen on their red blood cells. Answer: The approximate distribution of blood types in the U.S. population is as follows, and this pattern also varies globally based on your ancestry.

  • O-positive: 38 percent
  • O-negative: 7 percent
  • A-positive: 34 percent
  • A-negative: 6 percent
  • B-positive: 9 percent
  • B-negative: 2 percent
  • AB-positive: 3 percent
  • AB-negative: 1 percent

Inheritance

Basic blood type is a great playground for mentally studying dominant and co-dominant inheritance patterns using Punnet squares. If a mother has type A blood, what would be her possible genotype(s)? If a father has type O blood, what would be his possible genotype(s)? Is it possible for their child to have type O blood? Type AB blood?

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Bloom’s and Blooms

How to teach about flowers… or anything else.

I’m currently enrolled in the online course Online Teaching Certificate, which is about (you guessed it) how to teach… online courses. Ironically relevant repetition aside, it’s being superbly useful to me as an instructor with only ~4 years of formal teaching experience under my belt, because it’s serving as a thorough introduction to the principles underlying good teaching and effective course design.

My day consisted of 1-2 hours of grading before a scheduled phone interview this morning, 5 hours of teaching, at least 3 more hours of grading and prepwork for the remaining 1.5 weeks in the summer semester, and then ~2 hours of work for the online course. In the midst of all of this we’re trying to close on a house by the beginning of July. Oh, and I wrote this blog entry. 🙂

The focus of this week’s lesson was course design, with most of the discussion centered around the use of Bloom’s Taxonomy of Learning to design, teach, and evaluate successfully. It’s useful for students to think about these concepts as well, as it’s a helpful way to structure your studying.

IMG_20180620_191227381

Bloom’s Taxonomy

  • The first level of learning is simply to remember the relevant information (e.g. vocabulary words).
  • Then, you should be able to understand the information in context and apply it to scenarios (e.g. use it in an example).
  • Analysis adds your ability to compare and contrast related topics, and how they are organized so that you can troubleshoot (e.g. look for flaws or connections).
  • In truth, evaluation will require an even more thorough explanation of that analysis, with your added judgement and interpretation (e.g. choose the best of several methods).
  • Once you’ve those levels under your philosophical belt, you understand a topic well enough that you should be able to effectively create new content (e.g. a study guide).

What next?
You should find yourself constantly returning to those earlier levels of Bloom’s Taxonomy to analyze and evaluate your own work!

  • Are there errors?
  • Does it logically make sense?
  • Do you still remember the details?
  • Does the new material integrate ideas from each of the various parts of the issue?
  • Can you distill the topic to its core elements so that a 5th grader would understand you?

featured image: a giant bee in Bosque del Apache National Wildlife Refuge, Socorro, NM (July 2016)

Worried about time? Analysis? So is your neighbor.

You made it to Biology II, and you’ve realized it’s a completely different course than Biology I. Uh oh.

I asked all of my Principles of Biology II students this semester to share “Any concerns that you have about the class” after the first day. Here’s a peek at what y’all said, and some help! (I’ll update this later this week after lab students finish the orientation)

General worries…

  • Staying organized / Managing my time / Due dates – Find someone to help you be accountable. Meet, text, or email each other when you’re supposed to be reading the book/your notes. “This chapter’s killing me… are you doing any better?” Do you need music in the background while you study?
  • A lot of information / Multiple chapters per week – Review vocabulary terms & section headings first. Skim the chapter, looking for unfamiliar ideas. Mark those sections for extra time, and take notes about what you don’t understand. Don’t highlight everything.
  • Keeping up with notes during lecture – Focus on added explanations that I mention in class. Don’t try to write down every word – outline & use short notes – especially if it’s already on the slide (I post them on the course website). Many students print them or add typed notes on the digital pdf itself. This is definitely how I went through organic chemistry!
  • I’m not a science major / Missed the first week / Took biology I elsewhere / Struggled with biology I – Ask questions, and don’t panic. Use the course website to keep an eye on your grades. Ask for help early: Office hours (free…), STEM tutoring (free), making friends (okay, you might buy them lunch sometimes). I also post extra videos and activities that will give you another run through of many of the crucial topics, both for Biology I and II.
  • Study skills – Focus on understanding the concept, then fit the terminology into the broader story. Use active studying techniques – quiz yourself, write out answers to end-of-chapter questions, explain things to study partners out loud. Don’t make the mistake of thinking that re-reading your notes / chapter / flash cards is going to be the most effective use of your time.

Information worries…

  • Making the best grade that I can / Making an A – Shoot for the stars, and at least you’ll land on the moon. Read the study guides along with the textbook chapter when possible, so that you know what the most important topics will be. Find out why/how you answered wrong when it happens. Always aim for that A, and back up that ambition with solid, productive work.
  • The comprehensive final exam – Study Guides will be posted on D2L throughout the semester. Come to office hours and review exams I-IV after they are graded so that you understand why/how/when you chose the incorrect answers.
  • This class will be challenging – Certainly, but there is a bit less memorization than Biology I. The broader topics (evolution) are more intuitive to understand, though the taxonomy will require you to do the most memorization. Focus on understanding the concept, then fit the terminology into the broader story.  This class is designed to prepare you for amazing upper level courses – such as parasitology, ecology, & macroevolution. I also post extra videos and activities that will give you another run through of many of the crucial topics, both for Biology I and II.
  • I need to apply the information and think critically / How does this connect to everyday life – This is true in all of your courses, honestly. Stop and reflect on the WHY, HOW, and WHAT of the topic. You already use many of the concepts as part of how you adapt your decisions on a daily basis. Natural selection? Ecology? It’s all costs vs. benefits in a world of limited resources. You can often start by putting yourself “in the organism’s shoes,” but don’t take it too far. Many species do not have the same level of memory and self-awareness that humans do, and respond on a much more instinctual level.
    • Use logic to think through the possibilities.
    • Avoid falling into the teleological trap of thinking about what an organism “wants” based on your own ideas as a human.
    • Set aside belief. This is not a course on religion, opinion, or anthropology. Science is the search for truth about how the world works.

It helps to remember that you’re all in this boat together, even if your seats (your lives/backgrounds) are different!


Featured image: Science scarf and epic purple shirt – cool things from my mother-in-law and mom, both of whom love that I’m a college professor.

Since you asked… Mammals!

Sugar gliders vs. Flying squirrels

Sugar glider = marsupial, endemic to Australia & New Guinea
Flying squirrels = placental mammal, several genera distributed around the world

We briefly discussed these two organisms in class as an example of analogous traits: both have extended flaps of skin between their fore and hind limbs & use this skin to glide between trees. However, this is not a trait shared by all species in the most recent taxon they share in common (Class Mammalia), indicating that the characteristic is analogous instead of homologous. This is also an example of convergent evolution: The same type of trait developed independently multiple times, because of similar selective pressures on different species.

To see why these two types of organisms are only distantly related, let’s take a look at their taxonomic classification.

  1. Both are in class Mammalia: have hair & mammary glands, among other characteristics distinguishing them from reptiles.
  2. There are two large subclassifications of mammals: Those that have live birth (Metatheria & Eutheria) and those that have shelled eggs (Monotremes)
  3. Within those that have live birth: Eutheria (young protected and supplied with nutrition internally by a placenta, may also be nursed externally), Metatheria (no placenta forms to maintain the young, typically nursed in externally a pouch for an extended period)
    1. Sugar gliders are in the clade Metatheria, and are marsupials (infraclass Marsupialia) currently native to Australia (superorder Australidelphia): Their young are born very vulnerable and without fur. They have an external pouch, in which they nurse these young for ~110 days. Video
      • Not all marsupials have pouches either, though all nurse non-placental young outside their bodies.
      • Incidentally, females also have two uteri (uterus x 2) and males have a bifurcated penis, both of which are common in marsupials.
    2. Flying squirrels are in the clade Eutheria, and are rodents (order Rodentia): there are two main taxa of flying squirrels, one found in the Americas, the second found in northern Eurasia. All are placental, though their young are still born hairless and need a great deal of protection. They are still nursed (typically for at least a month), though not in a pouch. Video

For all practical purposes they both function similarly, but their physiological differences & the comparative immaturity of their young at birth are key differences between these two taxa.

The Story: Some time long after the evolutionary divergence between eutherian and metatherian mammals, natural selection in different locations favored the physical and behavioural characteristics that permit both sugar gliders and flying squirrels to glide.

The Value of “I don’t know.”

Can you ever answer an unasked question?

Allow yourself to admit that you need more time to answer, instead of stopping questions in their tracks.

Although it might seem most valuable (and good for your ego) to have a ready answer to every question, it’s basically impossible to know everything. By giving an answer that isn’t well-grounded in reality or is blatantly wrong, you actually risk others losing more confidence in your ability to teach, learn, lead, or follow, than if you simply admitted your ignorance. Same principle follows regarding admitting when you’re wrong.

MoreIKnow

Consider this: What do you risk by assuming you know?

  • Does a bad decision have potentially harmful consequences?
  • Are you excluding better options?
  • How do your actions affect others’ perception of you?
  • Is someone else relying on your statement’s accuracy?

Ignorance is a much simpler trait to alter than arrogance. 

We live in a golden age of information, with thousands – nay, millions – of free resources at our literal fingertips. As a professor, I would rather you learn the skills to find reliable answers than have you blindly follow the swift and volatile statements of the masses. Consider these questions below, along with applying basic principles of information literacy and pseudoscience analysis. (‘Cause I’m a student, that’s why.)

  • Is the answer you hear one that makes logical sense?
  • Does your source have an ulterior motive for providing the information?
  • Would this answer be likely to change if one aspect of it were actually false?
  • Are there many widely varying versions of this “correct answer?”

featured image: gold-tipped bottlebrush (Melaleuca polandii) in Armstrong’s International Garden (Feb 2017)

Mini “Huzzah!” Moment

It’s always a great moment…
…to see evidence that my students are paying attention in class.

  • The general Beer’s Law equation in the lab manual: Molecule Concentration = Absorbance(at a specific wavelength) * Constant
  • The general Beer’s Law equation I wrote on the board: [molecule]=A??? x constant
  • What several of my students put on the postlab: [molecule]=A??? x constant

There’s nothing really wrong with writing the “book” version, but it was nice to see that my simple version stuck with them.

Since you asked… Soap!

A student in Principles of Biology asked a question today that I didn’t know the answer to – are phospholipids the molecules in soap that facilitate its ability to dissolve both polar (carbohydrates, nucleic acids, and some proteins) and nonpolar (lipids and some proteins) materials?

The short answer: Nope! Soaps aren’t using any of the 3 major types of lipids, it’s a modified single fatty acid chain.

The longer answer: Sodium salt and potassium salt versions of fatty acids are the main active component of soaps. In fact the process of saponification serves primarily to separate the glycerol backbone from the fatty acid chains. This process results ionized chains in the solution, which then form ionic bonds with Na+ or K+ ions when salts are added to the mixture.

E.g. Sodium oleate: 

Salt form, found in soap

Comes from lipids containing oleic acid

1200px-oleic-acid-based-on-xtal-1997-2d-skeletal

Fatty acid form, found in phospholipids or triglycerides

Cheers for science & research!

 

The book-length answer: 
https://en.wikibooks.org/wiki/Structural_Biochemistry/Lipids/Soap

Nervous? Excited? So is your neighbor.

From freshman to returning grandmother, everyone has to go through that first day of a new class.

I asked my Principles of Biology I students this semester to share “Any concerns that you have about the class” after the first day. Here’s a peek at what y’all said, and some help!

General worries…

  • Finding the textbook – Armstrong bookstore, the textbook broker across from campus, Amazon.com, Chegg.com, Half.ebay.com … Just remember, you’ll need this book again for Biology II. Renting might not actually be the best option.
  • Staying organized / Managing my time – Find someone to help you be accountable. Meet, text, or email each other when you’re supposed to be reading the book/your notes. “This chapter’s killing me… are you doing any better?”
  • Keeping up with notes during lecture – Focus on added explanations that I mention in class. Don’t try to write down every word – outline & use short notes – especially if it’s already on the slide (I post them on the course website for you!).
  • Not sure what/how to read effectively – Don’t highlight everything. Skim the chapter first, looking for unfamiliar ideas. Mark those sections for extra time, and take notes about what you don’t understand.
  • It is a really big class – Well, you have the option to either stand out or blend in, but anyone is welcome to ask questions. There are also more options for who to study with! Also, my office is 50% less intimidating than most professors’ offices. Come by during office hours and ask for help.
  • Memorization – Know the story, memorize the details. Biology is always integrated, so make sure you can put the pieces together. Example: Facts – electrons are negatively charged. The valence shell is involved with bonding. Story – sharing & stealing electrons is the basis for constructing molecules, and the valence structure tells you how an element will bond.
  • This is my first college class / I have first year jitters… / It’s been 10 years since I was in school – Ask questions, and don’t panic. Use D2L/E-classroom to keep an eye on your grades. Ask for help early: Office hours (free…), STEM tutoring (free), Supplemental Instructors (free), making friends (okay, you might buy them lunch sometimes).

Information worries…

  • Making the best grade that I can / Making an A – Shoot for the stars, and at least you’ll land on the moon. Read the study guides along with the textbook chapter, so that you know what the most important topics will be. Always aim for that A, and back up that ambition with solid, productive work.
  • I might not catch on as fast as other students – Positive thinking + Positive action = Positive results. Reality check might be that you need to ask for help: Office hours (free…), STEM tutoring (free), Supplemental Instructors (free), making friends (okay, you might buy them lunch sometimes).
  • Not learning as quickly as I did in high school – Find out how you learn. Does it help if you draw everything? Do you need music in the background while you study? Take notes in class. Answer the questions at the end of the chapter – I’m not going to assign them like your teacher used to, but it will help you learn if you do them.
  • Have I forgotten my high school biology? – Maybe so, but don’t panic. Khan academy might be helpful, or CrashCourse. I post extra videos and activities that will give you another run through of many of the crucial topics. Send me an email or stop by during office hours.
  • Worried about the topics that I struggled with last time – Don’t psych yourself out, psych yourself up! You are going to knock them out of the park this time, because you are planning ahead, asking for help, and working hard. Remember to still study for the topics that you understood well, as it’s easy to forget the basics. What’s the mitochondrion do again?
  • This class will be a lot of work / will be difficult – Maybe so, but you can plan ahead. Do the assignments, be prepared, and find out why/how you answered wrong when it happens. This class is designed to prepare you for amazing upper level courses – such as parasitology, applied microbiology, environmental chemistry…
  • The comprehensive final exam – Study Guides on D2L are already posted! Come to office hours and review exams I-IV after they are graded so that you understand why/how/when you chose the incorrect answers.

It helps to remember that you’re all in this boat together, even if your seats (your lives/backgrounds) are different!


Featured image: Science scarf and epic purple shirt – cool things from my mother-in-law and mom, both of whom love that I’m a college professor.

New Semester, New Technique?

Humans love stories, but get bogged down by information.

“Shrimp wisely divide their time between eating, hiding from predators, and finding mates.”

“Shrimp respond to variable changes in their environment in order to optimize their caloric intake while minimizing predation risk and maximizing reproduction.”

Let’s be honest – it’s much simpler to understand the first sentence, but as scientists we’re expected to write the second sentence. The content is basically the same, although the details are variable.

Why do readers relate to the first version?
1 – less jargon (technical language)
2 – intuitive phrasing that connects the main ideas

Why is the first version problematic?
1 – less information, fewer details
2 – teleological (the shrimp has goals)

In teaching, can we reconcile the two? Can we use stories to help our students build mental models of the topics?

In an attempt to utilize one of the ideas that we discussed in our faculty reading round-table last semester, I am incorporating the idea of narrative sensemaking, or storied truths, into my biology lectures. The idea is to use sensible, intuitive stories to understand realistic, complex, patterns in the real world.

Good stories don’t just have to come from fantastical imaginings, rooted in the mythos of our ancestors. Scientific facts don’t have to be clinical and hyper-accurate in order to be useful. Just like a good teaching model, we can incorporate the best parts of both.

Why am I doing this?

Students are often frustrated by exam questions that require critical thinking skills, and say they are “too hard” or “not based on the lecture.” I am hypothesizing (Yep, I’m a scientist – I do this all the time.) that part of this problem is a mental disconnect from the material.  Many of the extra study materials that I direct my students to use are youtube videos (Hello, CrashCourse) or activities that have a clear, succinct, and entertaining story – they are more likely to mentally interact with the information more intuitively than if I were to simply remind them to “review section 7.3 in the textbook”.

Understanding connections is key to successfully studying increasingly complex topics in science, not simply rote memorization. Without the ability to think on their feet, analyze available information, and reach sound conclusions, they also are not productive, scientifically literate citizens. They can’t make connections if they don’t understand how the story works in the first place.

How am I going to do this?

I’m adding “What’s the story?” pieces to my existing lectures, in an effort to regularly remind students of the larger picture. My goal is to create 1-2 sentence story bits that aren’t just summary, but illustrate the narrative thread running through the past few topics for the section of material that we’ve just discussed.

For example, Chapter 1 of our Campbell Biology textbook discusses overall themes in biology. The first topic is the basic properties of life vs. non-life, moving on to where it is found. What’s the story? Life has adapted to deal with a wide variety of conditions.

What are the results?

I’ll let you know!


Featured image: Stalactites and stalagmites at Carlsbad Caverns (July 2016)

Healthy Eating Plate

Sometimes simpler is better.

Eat real foods, avoid hidden calories (such as sugary drinks), and exercise so that your body actually uses the calories that you consumed.

HealthyEatingPlate