Sunday, July 1, 2012

Evolution is Just a Theory - Theory vs. Law

The focus should not be between whether or not evolution is a theory or a law, as in, "I'll take evolution seriously when to goes from a theory to a law." Instead the debate should be between the theory of evolution going from a theory to a disproven theory. The distinction is important and I'd like to briefly outline why.

The usage of the word 'theory' in science is quite distinct from our normal, vernacular usage. In science, the term means 'model' or 'explanation' that incorporates a vast body of knowledge.

Other 'theories' that demonstrate the usage of the word 'theory' in science: cell theory (that tissue is made up of cells), germ theory (diseases and colds are caused by microscopic bacteria, protists and viruses), atomic theory (matter is composed of atoms), theory of gravity (the force of gravity is the explanation for the orbit of stars, planets, galaxies and objects to the Earth), theory of heliocentrism (the Sun is the center of the solar system).

This confusion is the source of some fun internet memes:



A scientific 'law' is not an explanation or model, like a theory, it's a simple statement of this does that. Newton's laws are a go to example--"A body in motion will stay in motion unless acted upon by an outside force". It offers no explanation like a 'theory' would, only a relationship--this does that. If we were to write that law as a theory we'd have to offer some explanation as to *why* it happened that way--something about mass, inertia, Higgs-Bosons, etc.

So in conclusion, the Theory of Evolution could *never* become a law because it could never stop being an explanation as to why biology looks the way it does today. That said, it could become something else--a disproven theory. All it would take for the theory of evolution to be disproven is one fossil, one organism, one anatomical structure, one DNA sequence, one piece of evidence that could definitely disprove common ancestry of life. It shouldn't be shocking that the Theory of Evolution has never become a law, but it should be unbelievably shocking that the theory has never been disproven. The Theory of Evolution has been under constant fire from day one 150 years ago and it has never once shown a sign of weakening. It has only gotten stronger as more evidence has been produced.

Sunday, June 24, 2012

Questions to Ask Yourself When Making Difficult Decisions

Below are a list of questions that I have found helpful when making difficult decisions. The contrast in my mind is between this, what I believe to be, helpful list and that of the unhelpful but more common list of questions that we ask our selves such as: "What will make me the happiest?", "What's the right thing to do?", "What does God want me to do?". Here's my list of helpful questions to ask yourself when making a tough decision:


What choice will I regret more not doing?

Over the years, this question has been the most helpful.  The source of its power is that it accomplishes several things. First, it gets you out the moment and into a hypothetical future scenario where you're looking back at your life from a much more objective position than you are in the present, decision-tense moment.  Secondly, it attunes you to your conscience and in a way that is much more in line with how our brain actually works.  Studies have shown that people regret losses and not doing things far more than they regret mistake decisions or things they've done.  In a clinical setting you can set up scenarios where you give people ten bucks or you can give them forty and then take away twenty.  Which do you think people would be more grateful for?  A small gain or a big gain accompanied by a loss?  People hate loss.  We hate missed opportunities, almost successes, relationships that could have been, jobs that nearly were ours.  

I read an article once written by a hospice worker that stated that when death bed patients look back on  their lives they hardly ever regret things that they've done at the end of their life.  They regret the things left undone.  They regret not loving their family more, not smelling the roses, not taking risks, not going out on a limb, not trying new things, not giving more. So, the next time you're making a tough decision, what choice will you regret more not doing?  A day may come when you're thankful you answered that question.

What choice is more adventuresome?

Life's an adventure.  Your either living an exciting adventure or a boring adventure.  Get off the damn couch.

What makes me feel most alive?

Howard Thurman once said,

“Don’t ask what the world needs. Ask what makes you come alive, and go do it. Because what the world needs is people who have come alive.”

What will I be most proud of doing?

I'm a firm believer that there is good pride (and certainly bad, too).  Good pride says, "I deserve better than to compromise.  I'm worth more than that."  Good pride isn't about comparing yourself with other people.  It's about comparing yourself with 'sin' and saying that you deserve better.


What fits with the narrative/story I want to write with my life?

This question, as the first did, gets you to take a healthy future reverse perspective, but it also gets you to think from an other's perspective.  If a hypothetical other were to read/watch my life, would it make a good story?  What would they think of my character?  Did I live according to my values?  Did I try and try and try and try?  Did I love well?  Think backwards, think outside of yourself.



What is the most fulfilling?

First off, I love the world 'fulfilling'.  I love its imagery--fill so full that your life is brimming over and spilling its abundance and wealth.  And I love how much better it is at capturing that than other synonyms--it's such a better word than happy (sounds like a painted on smile for a photograph) or joy (a little to saccharin for me).  Fulfillment is about feeling good way, way, way, way deeper than superficial happiness can ever reach.  It's about living according your conscience.  It's about making a difference.  It's about giving and loving well.  Fulfillment sleeps easy at night.

In my mind it's entirely possible to live a fulfilling life and not be happy.  I think of a single parent I know.  She works a ridiculous amount of hours at minimum wage; takes care of two kids and an ailing elderly mother; and pours her heart out for students at a church I used to go to.  I can tell by the way she loves people, talks about her job and the way she worships her God that she finds fulfillment in what she does even though her life is often very painful and difficult.  Life is tough, happiness is distant, but she is living life damn well and it's because she's living for fulfillment.

What will bring the most balance to my life? 

It's all about balance.  Between work, social, romance, pastimes, being tough, being soft, working, resting, breathing in, breathing out.  Answer this question and you'll be living rightly.

To which side do I err?

Instead of thinking in terms of actions (Do I do this, or do that?), think in terms of values (Which is more important?).  Recent examples in my life: Question: Should I go out with friends or study more?  To which direction should I err? Answer: err on the side of relationships. Question: Should I donate to this organization even though my budget is tight?  Which choice is better to err on the side of caution with?  Answer: err on the side of generosity and helping others.Question: Should I reach out to this estranged friend or not? Answer: err on the side of building potential relationships.  Values clarify and this question can help suss them out.



I recently realized that I should do a blog on this when it struck me how often I revisit this list of questions I had put together on a Google doc.  I hope they help you as much as they have helped me.  Best of luck with your next difficult decision.  :)

Sunday, May 27, 2012

Limiting Factors - Can There Be More Than One?

Limiting factor: a resource or component that constrains a population's size.

Examples: food, water, nesting sites, predators, parasites, reproduction rates, finite chemicals (iron, phosphorous, nitrogen, potassium, etc.)

Considering all those examples, doesn't it seem like there's more than one limiting factor at a time?  Don't they all affect the population at once?

Can there be more than one limiting factor at a time?

The answer, counter-intuitively, is no.  Liebig's Law of the Minimum states that there can only be one limiting factor and uses an analogy of a barrel:


The lowest slat prevents the water (which represents the population) from increasing any higher.  If that resource were to become much more abundant then the population could rise again to create a new limiting factor.  

Video illustrating this: 

I hear you objecting: Yes, but aren't all those factors acting at once on the organism's population?  Say, aren't predators and limited food both keeping the population low?  Both are acting on the organism's population, but the strongest force is the one keeping the population at the suppressed rate that it currently is.  If you were to change that one most limiting factor the population would rise.  Change anything else and it would stay stationary (in theory).

The below illustration is something I played with to also add time into the equation showing how that limiting factors can change and how there are secondary effects of either too much or too little of a factor.  For example, too little sunlight and a plant can't photosynthesize well, too much and the plant becomes scorched; too little water and the plant desiccates, too much and it drowns.  

To use a plant as the example again (because their needs are simple), an understory plant's population is limited by a lack of sunlight.  Say a tree dies, falls over and opens up the canopy.  The aforementioned plant's population will now rise to a new level.  That level will soon be constrained by a new factor, such as limited water.  If rain came, then the population would be constrained by limited space or a chemical necessary for photosynethesis such as nitrogen.  The assumption is that a species will always produce more offspring than survive and that it is in a constant battle of increasing its population and then having it constrained.

There are some scientists that would like to play around with introducing iron into strategic locations in the ocean to boost marine productivity (since it's a limiting factor for phytoplankton) and possibly offset global warming by absorbing an abundance of CO2. More here. 

This idea of the weakest link breaks the chain also has been used in many other systems scenarios, such as management, economics, health, government, et cetera.


Pix and vid:


Sunday, May 20, 2012

Why Women are Chimeras and Sex Determination

Genetically speaking, what makes a male a male and a female a female?  There is no uniform answer in nature:

Mammals (and some insects), as you well know, use a XX and XY system.  Essentially, if you have a Y chromosome you become a male...right?...

Reptiles/amphibians/some insects, on the other hand, use a system where if you have a different chromosome than the 'normal' you become a female.  In the lingo, you're male if you have WW chromosome and you're female if you have ZW.  *Note, the letter has zip to do with the shape.  I was told growing up that the mammal Y chromosome gets its name from the fact that it was shaped like a Y.  Not true.  It's a tiny 'x' and behaves the same as every other chromsome does, by crossing over during meiosis.  The 'x' terminology began because in early genetics they needed to give it a name and 'x' sounds cool.  ha

Some other insects have no sex chromosome, but instead the lack of an 'X' determines the sex.  They're either X or XX.

Plants, fungi, protozoans and inverts don't even use sex chromosomes altogether.

Exceptions within humans:

47 XXX - female
48 XXXX - female
47 XYY -- so called supermales
48 XXXY - Extreme Klinefelters males (a male with partial female development, like breasts, etc.)
48 XXYY - Extreme Klinefelters males

Then there's even more exceptions!  You can have XX males and XY females!  How's that?  Well, I kind of lied earlier when I said that it was the Y chromosome that make a male.  It's actually a few genes on the Y and those genes can get mutated or moved over to the X chromosome.  The most important controls testes development.  As embryos we're all females.  Then, if you have the right genes, the sex gonads get told to turn into testes.  If you don't have  that gene, then you develop as a female.

It gets even more awesome!

So, how do mammals deal with the problem of females having too many X chromosomes? If they displayed both of the chromosomes there could be some pretty dangerous developmental differences between males and females.  Well, they turn one off!  In fact, they don't just turn it off, they glom it into a blob on the side of the nucleus wrapped up in RNA and proteins in tombed so that it doesn't express.  What makes this awesome is that which X is randomly chosen.  It could be the one from the father or it could be the one from the mother.  

Translation: female mammals are mosaics!  Some of their cells use one X chromosome and some cells use the other!  Mammal males are roughly all the same genetically across their cells, but females aren't!  Their cells use different DNA!  In fact, you can have whole patches that use one X and other patches using the other.  This is called mosaicism, for obvious reasons.  In kitty cats this produces some fun fur patterns that are -only- in the females.  Basically, the dad had one color X and the mother another X and the baby displays both at once, but in different patches!  (Why patches?  Why not a blend of different cells?...Dunno.)


Barr Body in nucleus: 



Mosaicism in kitties:


This one could have happened other ways, but most likely was due to mosaicism.  One hint could come from if this cat is female.



Humans still have this.  For us the patches don't usually manifest as a calico/tortoiseshell appearance, but instead can have effects like ectodermal displaysia, which is the patching of working and nonfunctional sweat glands: 


There are other kinds of mosaicism, like that of so called chimeras, which are the result of fraternal embryos fusing together.  What makes this particularly wild is that this has been an issue with welfare genetic testing and for organ transplants.  One mother was accused of being a surrogate mother for someone and committing welfare fraud when a DNA test showed her as not being the mother of her kids (another article).  Another instance showed that a kidney transplant couldn't go through since the relatives weren't close enough genetically.

Chimerism





Pix:

Saturday, May 5, 2012

What Makes Something Sticky?

Bare bones answer: electrons being attracted to protons.

Molecules are collections of atoms.  Within that molecule the distribution of protons (positively charged) and electrons (negatively charge) is not even.  Often, but not always, there are more negative charges on one side and more positive on another.  The negative side wants to stick to another positive sided molecule and vice versa.  Broadly speaking these are called van der Waals forces or intermolecular forces  if the attraction does not share electrons (well, for the most part...).


Chemists and physicists further break those broad categories into dipole-dipole forces (between molecules of differing charge distribution), hydrogen bonding (also a dipole molecule, but with a higher contrast between positive/negative), and ionic interactions (between ions), London dispersion forces (temporary redistribution of electrons resulting in charge asymmetry) and others shown below.


You can see these forces in action with tape.  Stick some tape on a substance and then pull it up and some of whatever it was stuck to will invisibly now be on the tape in the form of stolen electrons (this shows there was at least some electron sharing, but not to the level of covalent or ionic bonds).

These two pieces were stuck together so that they now have the same charge and therefore repel each other

One piece was stuck to something and then removed taking some electrons with it.  It's attracting to the tape that wasn't stuck to anything and because of that didn't pick up any extra electrons and therefore has more of a positive charge.
Cool animation of all this: http://web.mst.edu/~gbert/INTERACT/intermolecular.HTM
Pic from: http://www.science.uwaterloo.ca/~cchieh/cact/applychem/hydration.html
Pic from: http://en.wikipedia.org/wiki/Static_electricity
*http://www.dummies.com/how-to/content/sticky-chemistry-intermolecular-forces.html
http://www.ccmr.cornell.edu/education/ask/index.html?quid=1118
http://www.npr.org/templates/story/story.php?storyId=12507754