A-Week: Evolution

Evolution is a controversial topic among the religious-at-large, but it isn't among scientists (many of whom are religious). When I talk about Evolution to people who do not believe in it, I usually find that they don't actually understand the Theory of Evolution. So, I'd like to address a couple of misconceptions about Evolution and then talk about why I would like you to take some time to sincerely consider the case for it. There is some technical info below. If you tend to get lost in such discussions, bear with me, I'll try to make it as understandable as possible. :) 

Let me take a moment to reinforce the following idea: I am NOT trying to disprove Creationism here. I'm not looking to take anything away from you. I'm merely hoping to add something wonderful to your world. My goal here is to clear up some misunderstandings about Evolution and hopefully get you to at least consider the possibility that Evolution is true. 

Common statements I hear about evolution (these are not strawman arguments, this are real quotes from people): 

"So, you think we all just came from monkeys? Why don't we see half-monkey-half-humans walking around?"

or another common form of this ...

"So, you think we all just came from monkeys? Then why are there still monkeys?"

No, I do not think we came from monkeys and the Theory of Evolution doesn't say we do either. According to the Theory of Evolution, we have a shared ancestor which is a very different thing. We didn't evolve from monkeys. Both we and monkeys evolved from the same starting point a long, long time ago. For example, I am supposedly descended from Charlemagne (at least that's what my grandmother's cherished ancient family tree says). If you were also descended from Charlemagne, it would be ludicrous to say that I came from you... and that's why it sounds so ludicrous when you hear people say we descended from monkeys. We simply have a shared ancestor. 

We might actually be seeing some evolution (natural selection) in progress! Artic temperatures are getting warmer and some of the ice barriers that have separated species for a long time are melting away allowing those species to mingle. The coolest, and most frightening, inter-species breeding that I've heard of is Polar Bears and Grizzly Bears. I kid you not. GROLAR BEARS! Imagine the carnivorous and unrelenting nature of a polar bear and now give it the climate adaptibility to come down from the snow into your hometown! Holy crap! :) Unlike inter-breeding between horses and donkeys which create mules who are unable to produce offspring, the Grolar Bears are continuing to spawn children. We have evidence of 2nd generation Grolar Bears. We could be seeing a new species emerging right now.  

Another example has to do with African Elephants. It appears that the African Elephant population is losing its tusks. This isn't because the elephants just decided to stop growing tusks. Some elephants naturally do not grow them and those elephants aren't targetted by poachers who want to gather ivory. The dead elephants who had tusks have less and less chance to produce offspring, while the tuskless elephants have plenty of opportunity to produce offspring. This causes more and more of the elephant babies to be of the tuskless type. This is an example of an environmental pressure that causes changes over time. If we continue to hunt and kill elephants for their ivory for a long enough time, elephants without tusks might become the "normal" elephants. (I'll provide some light, humorous reading on this topic at the bottom!) 

While random chance does have an influence in evolution (natural selection) over time, these types of environmental pressures and breeding opportunities to pass on genes are really the largest driving factor. So, don't think about it as a random occurance. The changes make a lot of sense when you can see the whole situation. 

Moving on to another common statement:

"It's only a theory."

That's true, but it's misleading because of a difference of language between scientists and non-scientists. Want to know what else is only a theory? 

Gravity. 

You've no doubt heard the phrase "Law of Gravity" which is a reference to Newton's Universal Law of Gravitation (the technical name), so you might be thinking "But gravity isn't a theory, it's a law!" Well, it was until Einstein came along and showed us all it was wrong. Newton's equations about gravity work pretty darn well for most intents and purposes that you and I encounter, but they break down on very small and very large scales. All modern gravitational physics is based on Einstein's Theory of General Relativity. 

My point here is that "theory" to a scientist doesn't mean "just a guess." It is something backed up by observational evidence. It is something which is able to successfully explain a question at hand, hopefully in the simplest method possible, and is supported by observation, experimentation, and other forms of evidence. When a scientific idea reaches the status of "theory" it has been thoroughly tested. When you think about the probability that a theory is true or not, this isn't a 50%/50%... it might be true, it might not be true. Just like our Theory of Gravitation which is based on Einstein's Theory of General Relativity, the Theory of Evolution is able to explain our natural world to 99.9999% accuracy. 

"There is no evidence for evolution."

This is a difficult response to overcome, not because it is true, but because there is so much evidence for evolution it is unlikely that anyone who has already ignored all of that evidence will accept any evidence I present to them. And yet... I will continue to try. :)

I could choose from lots of things, but I'm going to talk about one that I've been reading a lot about lately. It's called the Recurrent laryngeal nerve. It's the nerve that goes from our brains to our larynx. It's a pretty short trip, obviously, since our brain stem is at the back our skulls and is pretty darn close to our throats! The weird part though is that this nerve travels all the way down the throat, travels deep into the chest, and under the heart! It doesn't attach the heart at all, just travels underneath the aorta and THEN all the way back up the chest and into the throat to the larynx. It's quite a trip! This nerve exists in pretty much all mammals. Even in giraffes! This nerve is like 15 feet long in a giraffe because of the length of their necks! This nerve exists in other types of animals as well, even fish. It attaches to the gills instead of a larynx, but it comes from the same section of the brain and branches off of the vagus nerve just like in mammals.  

Ok, but why is that important? 

Well, in fish the path of this nerve makes perfect sense. Due to the position of the fish heart in comparison to the gills and brain, this nerve takes a very direct, short path. So, why does it take such a weird path in humans and mammals? Well, consider that evolution is true for just a moment and indulge me. Imagine a fish with this short, direct little nerve. Now change that fish just the TINIEST bit by making its neck a little longer. That nerve grows a little longer. Then make it a TINY bit longer and the nerve gets a little longer. At some point, the angle of the head starts to change in the TINIEST TINIEST bit. The neck starts extending, the heart is getting a little farther away and a little farther away and this nerve keeps getting longer and longer because the path it followed originally has been stretched out and shifted around a bit. As this continues, we get to a certain point where it makes more sense for that nerve to be completely re-routed so it doesn't go under the heart as the animal is getting longer, neck is changing shape ever so slightly, etc. However, to completely change the path of that nerve requires a HUGE change! It's much, much easier to just grow another millimeter longer and continue to go under the heart than it is to completely grow in a new direction. 

So, while it doesn't make any sense that this nerve should travel SO far in mammals (15 feet for giraffes!), it does make sense if you look at those mammals as the product of tiny, tiny, TINY changes over a very long time. 

Again, it is not my goal to tell you Creationism is wrong. I'm not making that argument. I'm only making the argument that Evolution is true and explains the natural world very, very well. I'm hoping you'll take some time to sincerely think about the ideas I've presented above. See if you can find a way to accept the amazing process of Evolution into your mind. No need to make it destroy something else... maybe just find a way to hold it as true in your mind along with your religious beliefs. 

Your promised humor: 7 Animals That Are Evolving Right Before Our Eyes