What is Evolution? - A Primer

There is a LOT of misinformation and misunderstanding over exactly what Evolution is. Partly due to general misconceptions and misunderstanding, mostly due to blatant misinformation. This will be my shot at clearing all of this up, in the most direct method I can.

What is evolution?[/b]

Evolution, put simply, is natural selection, coupled with variation and time within a limited area.

Natural selection states that that the organism best suited for the environment will thrive. Survival of the fittest. The early bird catches the worm, the fastest organism escapes, the best hunter gets fed at the end of the day.

Competition at it's best.

Natural selection is fact.

Variation is simply that... diversity in a group of life. Everybody looks different, you've got birds with huge wingspans, birds that cannot fly, dogs and cats of all different sizes and colors.

This variation can be brought on by many things. The inheritance of DNA from the parent organisms is the primary means. This opens the door for random mutation. Genetics is not perfect by any means. When an organism reproduces, it's DNA is passed on, and many times is flawed slightly. Some of these are detrimental (Down Syndrome, Fragile X), some of these are either pointless or annoying (ACHOO*, etc), and some are beneficial (a color change which is similar to the environment).

Variation in a species is fact.

Our world has limited room and limited resources. This is a fact.

Combine these.

1. A diverse population
2. Limited resources
3. Competition

You have an environment where life will favor those organisms which are best suited for survival. Those that do pass on their DNA. Those that do not will die. If you cannot chase down prey, you will not survive. If you cannot hide from predators, you will not survive. If you do not survive, you do not reproduce, your line ends.

Factor number four: Time.

Remember random mutation? This comes to the forefront REAL fast. Random mutation is exactly that. Random. It does not play favorites, it does not choose to work and not to work, it does not give a lifeform what it needs at any given time. Mutations can add, remove and/or modify genetic data.

The randomness is filtered by our friend Natural Selection. If you've got a bad mutation, sucks to be you. A good one? You're sitting pretty. Neutral? Well, no cigar, but you can throw the bones again. Although mutation does not play favorites, Natural Selection most certainly does.

Time puts this mechanism into motion. The environment dictates a situation. Life survives, changes and competes according to this situation. Over time, certain variations will prove to be the best for the situation given. The ecosystem will favor changes towards being the best for the situation.

Here's an example that many of you can catch onto: Yao Ming.

Environment: Basketball court
Species Variation: Players
Situation which brings about Natural Selection: The game

Favorable Mutation: Height

Yao is favored in the game because he's damn near seven and a half feet tall. This gives him a HUGE advantage versus his opponents. The environment favors his height.

Now, throw ol' Yao in a bobsled and you've got a problem. That environment does not favor his height. As such, you don't find any strangely tall bobsledders**

Put this into a more... natural situation. Why is Yao's height favored? He towers over all of his opponents, and he's much closer to that basket. Now, replace that basket with something like food hanging from a tree. If he can reach that easier than his opponents (competitors), then he will have more access to a source of nourishment versus everyone else. The shorter guys either need to find food elsewhere, get the food from the tree, or die.

This is again, an environment where height is favored.

Throw another log onto the fire. Take the short guys. What if, instead of finding food elsewhere and faced with the threat of dying of starvation, they find that the best way to get the food from that tree is to wait for the tall guys to snag it, then attack them?

Competition is cruel, but effective.

At first, it seemed like the short guys were doomed. Now they have a chance at survival. They just need to open up a 55 gallon drum of whoopass.

Guess what? The genetics that make them short will not go away because they're still reproducing. However, in their case, the environment will favor the ones capable of taking down the taller guys. The focus for change has shifted. Those that are faster and stronger will survive and reproduce, passing down THAT information.

Back to the tallies. They're now having to deal with aggressors. Competition from another angle. They either need to be able to fight, or get away. If they don't, they die. Let's suppose they choose the pick and run option. In these guys' case, speed along with height are favored.

One initial population.
One group survives based on height and speed.
One group survives based on speed and strength.

Species divergence. Speciation. We've observed this directly.

This is evolution. Changes in a population given competition, mutation and time.

Now, as I get into part two of this, let me put out two clear scientific definitions.

A fact in science is an observation.

A theory in science is an explanation of the observations.

This is why I said Natural Selection, our limited resources and genetic variation and mutation are all facts.

These changes have been observed. Models and predictions can be made. These changes can be reproduced in the laboratories. This makes them fact.

This also makes Evolution itself a fact.

"But Mister Sabz, I thought Evolution was just a theory!"

Ah, again a common misunderstanding. Evolution, which I have described, are the observed changes in life across generations over time. This is scientific fact.

The Theory of Evolution deals with the scientific explanation of how and why these changes occurred. "The Origin of Species" is an explanation of how evolution got us where we are now, all two legged and hairy.

Two different things.

The same can be said about gravity. Gravity's existence is fact. Nobody denies this. Great pain comes to the ones that try.

The Theory of Gravity explains how the force of gravity works. What exactly is gravity? How does it work? That we still aren't entirely sure of.

However, scientists do not debate gravity's existence. They do not debate evolution's existence for the very same reason. The debates that exist are in where all this ancient life we've found fit into evolution.

Again, a theory is an explanation of observed facts. A framework built by factual evidence and observations, used to explain the data we have found.

"What does Evolution have to say about the origins of life, Mister Sabz?"

Absolutely nothing.

That is, and never will be, a goal of Evolution. The origins of life have their own theories, and Evolution needs none of them to work. It merely needs life to exist, nothing more.

"What in the world are these 'transitional' things?"

Transitional fossils, or just transitionals, are fossils that clearly show a split in the evolutionary tree. Archaeopteryx is one good example. This shows a clear split from reptiles towards birds. Another is Tiktaalik. This clearly shows a split from fish towards tetrapods. Now, are these THE split? Probably not. However that's not the point. The point is that these fossils show a change that leads to these splits.

"You science guys say Cocelanth is a transitional. It's still alive!!!"

Evolution never says something has to be dead to be a transitional. Just because genetic divergence creates a new species, that doesn't automatically mean that the old one must die out.

Let's go back to our tallies and shorties. Suppose a group decide to take that "find food elsewhere" route, letting the tall ones and the other shorties duke it out. They migrate and find better grounds. They won't favor the changes the groups that stayed behind did. Any similar changes are favored for different reasons. So they've biologically got no need to march to the beat of that particular drum.

They, in this case, are transitional. They are also still alive, and will possibly split for whatever reason the environment dictates. Other things, including population isolation via geographic changes could bring about these effects.

Again, the fact that the changes occurred are not debatable. What IS debatable are how and why. That's the "theory" part of Evolution.


--------

I haven't covered every last one of the bases. I'll add as I go along, as the questions arise (and I know they will).




* I have ACHOO. Annoying as hell.
** Bobsledders, please correct me if I am in error.