“Student volunteers get hands-on experience growing and harvesting food using sustainable farming technology.”
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!
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.
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.
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.
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?
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.
You should find yourself constantly returning to those earlier levels of Bloom’s Taxonomy to analyze and evaluate your own work!
featured image: a giant bee in Bosque del Apache National Wildlife Refuge, Socorro, NM (July 2016)
Interesting history here about the changes to the US Pledge of Allegiance over the years.
American Christians frequently protest about removing the phrase “Under God” from the pledge, and a variety of groups field objections (on various grounds) to students not being required to say the pledge at all. While symbolically pledging oneself to the country is certainly a show of loyalty, the addition (or removal) of this phrase is most certainly NOT one originating with the Founding Fathers’ beliefs or guidance for this country.
Flag image originally from Brandon Paxton’s post on Facebook.
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)
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.
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.
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.
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.
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.)
featured image: gold-tipped bottlebrush (Melaleuca polandii) in Armstrong’s International Garden (Feb 2017)
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?
It’s always a great moment…
…to see evidence that my students are paying attention in class.
There’s nothing really wrong with writing the “book” version, but it was nice to see that my simple version stuck with them.
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:
Comes from lipids containing oleic acid
Cheers for science & research!
The book-length answer: