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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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)

It’s smart to admit when you’re wrong.

An article by Business Insider recently highlighted the “five most fundamental differences between smart and stupid people,” and it doesn’t read like the success self-help book you’d expect.

“In a situation of conflict, smart people have an easier time empathizing with the other person and understanding their arguments. They are also able to integrate these arguments into their own chain of thought and to reconsider their opinions accordingly.”
-Lisa Schonhaar, Gisela Wolf: Business Insider 

My mom and I have recently been discussing the sticker (and t-shirt) she gave to me as a birthday gift, both of which include this exasperated saying: I Can Teach It To You, But I Can’t Understand It For You. She shared this article with me, which highlights empathy, cooperation, critical thinking, and honesty as some of the most telling characteristics of smart people.

How smart is your attitude?

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

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

Professors Disappear at the end of the Semester.

Well, at least I do. It’s been a very busy past 2 months, and I’ve been busy even amongst the grading and teaching too. What have I been doing? Earth Day March for Science, visiting family, cheering on spring blossoms.

Being science-y.

And being nerd-y. How? Dungeons and Dragons, of course. Can’t go wrong with the classics. My current character is a Norse skald (bard) from ~800 CE, and we somehow managed to sail from Midgard to Vanaheim – magic is much cooler there, but there are were-beasts, and two moons. I’ve been playing a lot of Dragon Age: Inquisition and Origins, especially since I turned in final grades. Solas and Blackwall are two of my favorite characters, and I’ve started writing a Solas + Inquisitor fan-fiction “A Long Hunt” to show my love for it. Later chapters of the fanfic will definitely be NSFW.

Being nerd-y

What am I up to next? I’m teaching future K-5 teachers how to “Do Science” in the course Earth and Life Science for Early Childhood Education Majors, so I’m preparing materials for starting June 5th.

Food for Thought – And Eating.

A discussion of biodiversity and the role of fungi as decomposers turned into a chat about “expired” bread today, and afterward (while making a sandwich with “expired” bread) I decided that they could probably benefit from a little bit more concrete advice to back up our discussion. One of the students asked how they [the bacteria and fungi] got to the food after you put it in the refrigerator. We talked about what preservatives are and the balance between safe consumption and preventing organisms from growing in the food, and about the fact that the fungal spores and bacteria are in the air and on the surfaces all around us. After a few incredulous looks after discussing moldy bread, I threw up my hands and gave in. “Look, I couldn’t tell you just how many products in my fridge right now are past their printed dates, and they are perfectly safe and good to eat. There are plenty of other foods that don’t have expiration dates on them either because – for example – it’s just a raw carrot.”

This is what I shared with them after class, and is generally my guide for why I continue to buy short-dated products and tear moldy bits off of bread and eat the rest.


Since I wouldn’t want to provide advice without evidence… a bit more information about so-called “expiration dates” on perishable products such as bread. 

My version: The dates are advice from the manufacturer and/or a regulation agency, and their purposes are two-fold: Sell products that you are pleased with, and reduce the chance of you from being harmed by the product. Use dates as guidelines for how fresh a product is so that you can plan to use the food within an appropriate amount of time. The dates are more likely to be indicative of food quality and how quickly it should be sold, and is not a deadline for using the product.

IMAG0007

Evidence: Bread with a March 01 “Sell-by” date, which was slightly dry but still delicious and not the slightest bit moldy. 

Learn about food safety, especially the types of foods that tend to develop harmful bacteria or fungi that are likely to be hazardous to your health. And you should always know how to handle your food safely! Safe cooking is just as essential as safe storage. Keep in mind however, that all of this information from the USDA below is based on customs and policies in the US and is general advice covering a range of foods and people, and additionally does not always reflect the rest of the world.

Use good judgement, and know your own body. I have a strong immune system from years of living in the country on a farm and I have an in-depth working knowledge of how organisms live and survive, so I’m likely to make good decisions about the safety of my food. If you don’t exercise good judgement, there will often be consequences – just as there were for our early human ancestors 2,000,000 years ago (Yes, 2 million years ago).


Info from the USDA about labeling: https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/food-labeling/food-product-dating/food-product-dating 

Are Dates for Food Safety or Quality?
Manufacturers provide dating to help consumers and retailers decide when food is of best quality. Except for infant formula, dates are not an indicator of the product’s safety and are not required by Federal law.

How do Manufacturers Determine Quality Dates?
Factors including the length of time and the temperature at which a food is held during distribution and offered for sale, the characteristics of the food, and the type of packaging will affect how long a product will be of optimum quality. Manufacturers and retailers will consider these factors when determining the date for which the product will be of best quality.

For example, sausage formulated with certain ingredients used to preserve the quality of the product or fresh beef packaged in a modified atmosphere packaging system that helps ensure that the product will stay fresh for as long as possible. These products will typically maintain product quality for a longer period of time because of how the products are formulated or packaged.

The quality of perishable products may deteriorate after the date passes, however, such products should still be safe if handled properly. Consumers must evaluate the quality of the product prior to its consumption to determine if the product shows signs of spoilage.

Food Safety Tips from the USDA: https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/safe-food-handling/basics-for-handling-food-safely/ct_index 


Featured image: Perfectly safe, delicious bread that was discounted 3 weeks ago because of the March 1st sell-by date. 

The Scientist

Scientists don’t think the same way as your average person.

What does that mean? Well, it means that we’ve trained our minds to use a particular set of skills that many people don’t understand or actively avoid using. Often those who pursue science have natural tendencies toward curiosity and information, and a quicker grasp of numerical analysis than others, but not always. Many of us are simply passionate enough about science to buckle down and learn the mindset that a scientist needs.

One skill is the ability to objectively analyze information.

We don’t just nod approvingly, our minds latch onto bits and pieces of everything that comes our way. From behavioral patterns to mathematical models, we are surrounded by information that is often raw and complex. Information alone doesn’t do anything for us, it isn’t good, or bad, or helpful – it exists, with that existence having inherent value and potential. Scientists are the ones who use that potential, those who look for the reality of what is truly there instead of just skimming the surface.

This skill comes in two flavors, and not everyone likes both equally.

First, there is the ability to dig deeper and deeper into the minute details. Taxonomists, chemists, and molecular biologists are examples of those who use this skill extensively. They need the attention to detail, the patience, and the dedication to catalog all  of the differences between two species, or to analyze thousands of samples of DNA looking for a matching sequence across taxa. Often, this is described as a reductionist analysis of the world. Application of objective analysis in this way leads us to further understanding of precisely how things work and what they are.

Second, there is the ability to analyze patterns and interactions at the scale of whole systems. Ecologists, sociologists, and climatologists are examples of those who use this skill extensively. These scientists need to integrate information from a variety of sources and find out how everything fits together, how individuals and parameters are connected, and determine the consequences of a series of changes. They are often dealing directly with the emergent properties of a system, rather than with the individual cogs in the machine. Application of objective analysis in this way results in a better comprehension of what happens and why it can happen again.

A second skill is the willingness to step back from our beliefs.

Scientists rely on evidence. We search for evidence, analyze our evidence in the form of data, build our models out of pieces of evidence, and sometimes change the world by finding evidence to support new ideas about the world. Yes, new ideas about the world. The importance of this skill is that every good scientist inherently understands that they are actively seeking to determine if they are wrong. We make the absolute best hypotheses possible, that logically could be right and are based on the most complete information at the time. And then we set out and dedicate ourselves to finding the truth.

Falsifiable hypotheses, experimental controls, and large sample sizes are all tools that we use to try to find the truth. And yet all of those tools are useless indeed if we ignore the result of their dedicated application. What happens when we are wrong? First, we determine just how much we can trust that answer. Did we collect reliable information? What might have gone wrong? This is also where statistics comes into play. Second, we accept it and determine the consequences. We know nothing – we seek everything. In reality, what this means is that we do change our minds sometimes (We thought the world was flat until evidence indicated otherwise, remember?). Additionally we end up accepting contradictions as an inherent part of reality.

Perhaps the evidence didn’t support my hypothesis because I don’t know enough to write the correct hypothesis yet.

socrates1

“I know that I am intelligent, because I know that I know nothing.” -Socrates


Why? What is it about these two skills that often sets scientists apart?

One reason, in my opinion, is that humans have a deep desire for the status that comes with being right. James Gee discusses our desire for social status and the need to support our “family” in his book The Anti-Education Era, and these are traits that do help us survive. We are inherently social animals, and being wrong can, quite frankly, sometimes have devastating consequences. Not only do we want to be right, we also want to be with others who are right because of the direct and indirect benefits we gain.

Consider this: “Do you want to rely on someone who says that they might be wrong?”

This is the kind of mental construct that exists to some degree in all social organisms, and it developed entirely outside of (and prior to) the construction of formal scientific methodology. It is a Darwinian safety mechanism that has been built over time because bad decisions have consequences – often death. The result is that most people tend to hesitate in following someone that has been wrong in the past.

Consider this: “Can you trust someone who refuses to admit that they could be wrong?”

Aye, there’s the rub. We are also aware of our own fallibility. Since we are capable of being wrong, there is always the possibility that we are at this moment, actually and truly wrong. This understanding of ourselves and others logically leads to skepticism that also benefits our survival, and someone who refuses to accept this possibility can (and should) seem insane and untrustworthy.

The Conundrum: A need to be skeptical of both those who state that they can be wrong, and of those who state that they cannot be wrong. 

Thus we see how trust in scientists is so easily lost, and how people can so easily be misled. We see why scientists rarely become celebrities, and why bad ideas that don’t kill you can spread like wildfire.

A second reason is the fear of the unknown, resulting in the construction of explanations independent of evidence. This is based in part on the concept of “mental comfort stories”discussed by Gee, as he illustrates how much our happiness and contentment about the state of our lives often relies on not challenging these comfort stories. Effectively, humans often reap benefits from ignoring evidence that contradicts their long-held beliefs.

Consider this: You (most likely) hold some beliefs for which you have no supporting evidence, besides tradition. Holding to those beliefs hasn’t killed you, and probably makes you happy and accepted by your community. 

So, what is wrong with this situation? You benefit from the mental comfort story (perhaps about god) and no one is harmed, right? Well, that is only true until you encounter a community that doesn’t hold those same beliefs. Then, those unsubstantiated claims might very well cause people in both groups to die, and will at least make people unhappy and unacceptable to the opposite community. Who is wrong? Is there any way to tell? No, because the ideas weren’t based on evidence in the first place – they were based on what comforted people, made them accepted and content with the world around them.

Consider this: You are shown evidence that contradicts your beliefs (perhaps about ethnicity/race), and you refuse to alter those long-held beliefs. Although you are happy that you’ve upheld your beliefs, the consequences can be major – losing your job, failing a class, being arrested because of your actions.

Well, you now have 2 good reasons to change this particular belief, but if you’re like most people, you won’t. The evidence indicates that your belief is wrong, and there are negative consequences to holding your belief. Perhaps you decide to split the difference – to not act on your belief in a way that causes problems such as being fired, but it will still make you unhappy. Or you decide to deal with the consequences so that you can remain happy and accepted by your chosen “family.”

The Conundrum: Some beliefs cannot always be conclusively shown to be right or wrong, and the resulting conflicts can be devastating. Other beliefs can be demonstrably wrong, and upholding them in the face of evidence can also be catastrophic.

What is the scientist’s solution (and Gee’s)? Use the skills of a scientist – objective analysis of reliable evidence & an open mind.

Evaluate your ideas with evidence whenever possible. Do not continue to hold beliefs that are conclusively false. Not only is this illogical, it will eventually have consequences for you and/or your society.

Build and use your mental comfort stories when there is no way to find the truth – but be open-minded. Other people with varying perspectives can hold ideas that are different from your own, and you should allow them that to retain right so long as it does not cause you harm. If it does, then you have the ability of any organism to make decisions that benefit your survival. You should feel free to try to convince them that you are right, but understand that typically neither of you has any evidence, and both ideas may be equally valid.


A social community for researchers, mostly scientists: ResearchGate


featured image: A grass shrimp (Palaemonetes pugio)