Sunday, August 2, 2015

Tuesday, July 14, 2015


New Horizons came closest to Pluto today, releasing some amazing images!  So sad Pluto was demoted from planet status before we got there, but this is still really exciting, and more pictures will be out tomorrow.
Click here to read more on NASA's website.

I couldn't resist making this meme, since so far it looks like no one else has (which surprised me). What else do you do when you have a planet with what looks like a giant heart on it? hah

I love you to Pluto and back

Stay curious!
~Bio Geo Nerd

Sunday, May 17, 2015

Marie Tharp - Geologist

Marie Tharp was responsible for verifying Alfred Wegener's theory of Continental Drift, a key Theory in Geology.  Read all about her in this amazing article on mentalfloss "How One Woman's Discovery Shook the Foundations of Geology".

Wegener's was a theory the scientific community only laughed at when presented in 1912 until all the evidence came pouring in and staring them in the face many years after Wegener's death.  The theory was laughed at, and according to Marie Tharp's recollection, you could even be fired from geologic work for believing his theory.

As an aside, here's a fun video on Wegener

Even when Marie Tharp first showed the evidence - a map she had made from radar data of the sea floor which clearly showed the mid-ocean ridge where sea floor spreading takes place and allows for continental drift - to her colleague in the 1950's, he made her redo all her hard work mapping the seafloor because he couldn't believe it backed up Wegener's Theory and pegged it as only "girl talk".  She started from scratch and came up with the same thing, which also was corroborated by this colleague's own data of undersea earthquakes.

This laid the way for Harry Hess to peg Seafloor Spreading as the mechanism for Continental Drift.  Wegener and Hess are recognized as the fathers of Plate Tectonics in modern Geology.

I'm going to go out on a limb and consider Tharp as a mother of Plate Tectonics!  The only reason she wasn't out on research ships collecting radar data herself for this work was because they wouldn't allow women on ships- it was considered bad luck.  In fact the only way she even got to study geology was because after Pearl Harbor, universities finally opened up their programs to women.  Marie Tharp is not well known, but she managed to triumph over the sexism of the time and is now one of my heroes.

This post was spurred by this amazing article, which goes into detail about what Marie Tharp did.  Do yourself a favor and read it!  (Picture also from there)

Wednesday, March 4, 2015

The Teen Brain

Can I just tell you how much I love teenagers?  I am student teaching at a high school and I thoroughly enjoy being around these young people, with their varied personalities, interests, challenges, goals, etc..  I obviously adore science, but these kids make my job so great I'd probably still like it even if I didn't get to teach about my favorite thing ever. I just wish they all knew how awesome they are and can be.

Adolescence is a really interesting conundrum in the development of a human being.  It's an exciting time that leads up to so many big life changes- getting through school, choosing a career, starting a family, making a place for oneself in the world.  So many physical changes are happening, not the least of which are the changes in the brain.  These changes make it both easier and more difficult for people to become responsible adults, which is one reason it is so incredibly fascinating, and makes me truly appreciate and empathize with teenagers that much more.

An explosion of brain development
It is well-known that humans go through an explosion of brain development during the first 3 years of life.  Infants and toddlers are actively exploring their worlds and making many connections in their brains.  But did you know this explosion also happens in adolescence?  And interestingly, an important part of this development is cutting away parts that are no longer needed.  This process is called "synaptic pruning".

Synaptic Pruning
This term refers to the "synapses" which are the connections between brain cells.  Cutting those away may seem counter-intuitive, but it is actually a wonderful part of developing a faster, more efficient brain.  It's a very exciting time for learning.
Here are some photographs taken through a microscope of brain cells at various ages.  Notice how there is an explosion of growth as the baby develops, and then as they become school-aged, things are pruned away while what's left becomes strengthened.

I have put in a couple of great video clips to explain this process.

Short, student-friendly explanation:

More detailed (fascinating!) info on synaptic pruning - TED talk by Sarah-Jayne Blakemore:

Prefrontal Cortex Development
If you watched that second video above, you heard a lot about how the adolescent prefrontal cortex is developing.  This area of the brain is very important for higher-order or "executive" functioning skills.  That includes things like planning, predicting consequences, impulse control, and personality.

So the interesting thing is.... this area of the brain is not fully developed in humans until around age 25!  Does the sometimes irrational behavior of teenagers make more sense given that information?  Teens are very prone to risk-taking, which makes sense given the fact that they are still learning how to control impulses, predict consequences, and make good decisions.  This lower impulse control can also be an amazingly good thing!  So many people have made amazing discoveries, inventions, etc. while in this stage of brain development, because they had all the drive to go for their goal, without their brains putting the brakes on.  So while impulse control is super important, sometimes it can be overdone and stifle creativity.  Without that fully in place, teens can do some amazing things - amazingly stupid or amazingly creative and exceptional!

Societal influences
So the conundrum I mentioned is that a teenager has this amazing brain with abilities and creativity, but heightened propensity toward risk taking and foolishness and less ability to control those impulses.  And yet this is a time period when people are expected to make really important decisions that will shape the rest of their lives.

It is also a time when many young people are filling those moldable brains of theirs with garbage!  Not just garbage that will prove pretty useless in the future, like Angry Birds and Candy Crush.  But garbage that is going to forever stunt their progress and could even ruin their lives. Alcohol, pornography, and drugs can wreak havoc on a developing brain and the person whose head it's in.  But those are the things that are exciting and new, and the teen hasn't yet developed full ability to put the brakes on.

That, however is NOT an excuse.  It is important for teenagers to realize the limitations of being a teenager and rely on advice of parents, guardians, teachers, and other trusted adults to help keep them safe.  It makes perfect sense that we strive to educate young people about staying away from risky things like drugs before they even get to be teenagers.  If a young person can decide while they are a child that they will say no to drugs, no questions asked...that choice has already been made and they won't have to grapple as hard with it later on.  They will also be helped by the added protection of choosing good friends who have also made similar choices for themselves.

So to wrap this up.... teenagers are awesome creatures.  They have a LOT of brain work to do, while working with a less developed instrument than those of adults.  They need good adults who will support and guide them.  Do what you can to help educate them, but above all, love them and cut them a little slack.

Thursday, January 1, 2015

Your Metabolism Doesn't Know It's The New Year

This is a more scientific, detailed continuation of a discussion started on my other blog.  Fat Fun Fit: Why I'm Not Making Resolutions: A Case Against Dieting.  From that post (in blue):

How will your body react if your norm is to eat around 2,500 calories per day, and only a little walking as your physical activity, and you suddenly cut your food intake by HALF and jump up to a "perfect" workout regimen?  My body reacted like this, as would most:  "Holy crud!!  What the hell is going on?!!  We must be starving, and running to try to find food! What apocalypse is going on out there?  Oh man, this is it, this is the end.  Emergency!  Emergency!  Going to code red- crisis management mode!"  My body senses a sudden catastrophic world event on many January 1st's.

Now time for the science nerd in me to come out.  What happens physiologically while on a low-calorie diet that your body is not used to, is that all food coming in as much as possible will be stored as fat for later in case the emergency gets even worse, and muscle gets broken down to be used for quick energy.  Cause if you're in a crisis, keeping your brain well-fed, and planning for the worst is top priority.  Your brain is not able to use energy from fat, and if you are starving your brain by eating a severely low-calorie diet, muscle is the quickest way to get energy to your brain.  Your body doesn't really have a way to tell how much fat it already has stored so that it can "cap" it at a certain amount, which is why you can get very morbidly obese people.  Your body will just keep making more fat when it is in these crises even though you already have a lot, or when there is a plain old excess of energy coming in.  Losing that muscle lowers my energy and makes sustaining this plan much more difficult.

Continuing on....

Your brain needs glucose.  Your body does too.  It's the energy that gets broken down into usable energy for your body, known as ATP.  You can also use other simple sugars like fructose, but those actually just get converted to glucose before being used to make energy.

Glucose can be stored in a number of ways.  The easiest way is as glycogen.  That is a ginormous molecule of glucoses linked together in a network.  Your liver and muscles store glycogen so that your body and brain have enough energy between meals.  They can only store enough to last for a few hours (between meals).  When there is no glucose in your blood from a recent meal and there is a need for energy, the glycogen gets broken down to glucose.

In the muscle glycogen, the glucose is used right there in the muscles so you can still walk around, type at your computer, chase your kids, etc. between meals.  The liver is the bank account for your brain.  The glycogen in the liver is broken down to send glucose into the blood for the brain to use.  Brain always has priority.  If the brain doesn't get enough, the body must supply.

When glycogen is gone, the body will go to the next source.  Muscle.  There are a lot of Amino Acids - building blocks of proteins - in your muscles, cause that's what muscles are made of- loads and loads of proteins.  Those proteins can then be made back into glucose to send to the brain so it has energy.  This process is called gluconeogenesis  (gluco=glucose, neo= new, genesis= make;  make new glucose).

When you are on a very low-calorie diet or starvation, your body will break down some muscle to feed your brain.  In the absence of readily useable glucose in the diet, the same happens.  This is why people on Atkins/ low carb diets lose a lot of weight quickly at the beginning.  They are starving their brains of glucose, so the muscle gets broken down.  Well, muscle weighs A LOT.  It is much more dense and heavy than fat.  It also takes a lot more water to metabolize muscle, so the majority of those pounds you are dropping on those diets are muscle and water.  Great if all you care about is the number on the scale.  Terrible if you care about your body composition, shape/ size, and actual health.

The other way for glucose to be stored is for PARTS of it to be put into fat. Glucose has 6 Carbons in it, but a bunch of 2-carbon subunits (Acetyl-CoA) can be put together into a long chain: a fatty acid.  Then 3 of these chains can be attached to a glycerol and stuck in adipocytes- fat cells.  A lot of energy can be tucked away this way.  You get loads and loads of energy out of fat.  You are probably familiar with this if you pay attention to nutrition labels.  There are 9 Calories per gram of fat, but only 4 Calories per gram of carbohydrate or protein.  That's equalizing the weight.  Fat takes up a lot more space, so all that extra energy stored in your body also makes your body bigger than the same amount of energy stored in muscles or glycogen.

So, how and when does this fat energy get used?  That's the tricky thing.  Your brain lacks the proper gateways and enzymes to metabolize the subunits from fatty acids (acetyl CoA) directly.  It can only take in glucose or ketone bodies.  The glycerol from the triglyceride can be made into glucose, so those get sent off to the liver to do that.  But the fatty acids are better used by the cells of the body cause they have the right enzymes and gates to allow that to happen.

But since fat is long-term storage, just like a trust fund, the body is not going to break into it at the first sign of trouble.  It waits to see if it can get by with the cash on hand, the checking and savings account.  (Glucose in blood from your meal, then glycogen, then muscle as explained already.)  Then if it's dire enough it will go for those fatty acids IF the body is in need of it.  So, from what I have heard from a Physiology professor about some research (but haven't located the research myself yet so I have no link, sorry), is that the mark for the fat getting mobilized is about 45 minutes of exercise.  After that point you would start to break down the fat for your body to use.  So the recommendation of 30 minutes of exercise most days doesn't even touch that.  If I want to reduce body fat, the best thing is to go on hours-long hikes as much as possible.  (The regular aerobic exercise IS crucial to your health in other ways though, and should still be maintained for your cardiovascular, respiratory, muscle and mental health.  Benefits of regular exercise are nearly endless.)

I mentioned the brain can use ketone bodies.  In severe starvation, the fatty acids can be made into ketone bodies, which can get into the brain and used for energy.  But they are very dangerous because they turn the blood acidic and it is detrimental to your body.  This is the last ditch effort during severe starvation, to keep your brain alive, cause without your brain, the show is over.
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