Evolution is a SCIENTIFIC FACT. Though regular non-scientific people throw around the word "theory" like "it's just an unproven idea", that's not the scientific meaning of "theory". When scientists use the word "theory" they are referring to a thorough collection of solid evidence-based facts carefully collected over time, united by the common thread that connects them.
In the case of Evolution… it has almost nothing to do with “monkeys”. Forget about monkeys.
The essence of Evolution is just this: Offspring tend to look like their parents… but not exactly like them. This is something everyone knows. It’s obvious. Offspring tend to look like their parents… but not exactly like them. And Evolution simply extends that obvious observation over time: A certain tiger's great-great-great-great-great grandchildren will probably tend to have similar features, like the same number of eyes, legs, toes, etc. You wouldn’t expect them to grow wings or scales or a trunk, or be 20 feet tall.
But sometimes that sort of thing does happen. Animals can be born with birth defects, i.e. mutations. And if they should happen to pair up with someone who shares that mutation, there’s a high percentage that their children, grandchildren, etc will carry on that mutation as well.
Added up over many thousands of years, those little series’ of mutations can create a line of tigers that is significantly different enough that you pretty much have to call it a different species of tiger.
That’s all Evolution says -- it says something that’s really obvious and undisputable. Your kids look similar to you but slightly different. After many generations, it’s perfectly sensible to imagine that certain lines of descendants could look quite different. But you still expect them to be basically the same. That’s all it says. Likewise, if you go backwards through your history, you expect to find the same thing — that your great-great grandparents had the same number of limbs, 5 fingers on each of two hands, a similar looking skull, same number of teeth, same number of bones. But if you go back far enough, you’d expect to eventually find a generation where everything was exactly the same, but ONE thing was different. And if you dig a little deeper you’d find another ancestor that was exactly the same as the previous, but ONE thing was different. You don’t expect them to have 8 limbs like a spider or crab or to find evidence that your ancestory lived in a shell, like a snail. You expect them to have exactly the same features with only slight variations, precisely because science is all about reasonable conservative expectations.
And it turns out, as you would reasonably expect, that those reasonable conservative expectations based on common-sense observation and simple logic have been verified over and over, millions of times. Geologists are able to determine the age of layers of the earth, paleontologists are able to determine the age of fossilized bones, and biologists are now able to map recovered DNA and detect exactly how many mutations have occurred between a certain generation and our current one. And with all of their factual evidence — factual in the sense that “this fossil is from 180 thousand years ago, this DNA sample is different in 350 places from current DNA” — the goal is to reconstruct the puzzle of ancestry in the most conservatively sensible way possible. (And scientists will debate until the accepted reconstruction is as conservative as possible without leaving out any pieces.)
And that’s all it's about. Reasonable conservative expectations. Of course the most conservative expectation possible would be that your kids look exactly like you, and their kids look exactly like you, and that when you reproduce, you’re passing along a clone of yourself. Obviously that’s not the case. Your kids look different. But in terms of overall human features, they look pretty much the same, and the DNA confirms that — the differences are superficial. But you expect that somewhere along the line, there will be “birth defects” (mutations) and some of those will get passed along. And after many thousands of generations, quite a few of those mutations will have been passed down the family tree in many different directions. Some of those great-great-times-a-thousand-grand-children may decide not to have kids. Many have a small number of kids. But then you get that one line of families who has so many kids generation after generation that they outnumber every other descendant… and pass along a HUGE number of those mutated genes. And suddenly your “family tree” begins looking a lot different.
That’s evolution. That’s all it is.
In the case of Evolution… it has almost nothing to do with “monkeys”. Forget about monkeys.
The essence of Evolution is just this: Offspring tend to look like their parents… but not exactly like them. This is something everyone knows. It’s obvious. Offspring tend to look like their parents… but not exactly like them. And Evolution simply extends that obvious observation over time: A certain tiger's great-great-great-great-great grandchildren will probably tend to have similar features, like the same number of eyes, legs, toes, etc. You wouldn’t expect them to grow wings or scales or a trunk, or be 20 feet tall.
But sometimes that sort of thing does happen. Animals can be born with birth defects, i.e. mutations. And if they should happen to pair up with someone who shares that mutation, there’s a high percentage that their children, grandchildren, etc will carry on that mutation as well.
Added up over many thousands of years, those little series’ of mutations can create a line of tigers that is significantly different enough that you pretty much have to call it a different species of tiger.
That’s all Evolution says -- it says something that’s really obvious and undisputable. Your kids look similar to you but slightly different. After many generations, it’s perfectly sensible to imagine that certain lines of descendants could look quite different. But you still expect them to be basically the same. That’s all it says. Likewise, if you go backwards through your history, you expect to find the same thing — that your great-great grandparents had the same number of limbs, 5 fingers on each of two hands, a similar looking skull, same number of teeth, same number of bones. But if you go back far enough, you’d expect to eventually find a generation where everything was exactly the same, but ONE thing was different. And if you dig a little deeper you’d find another ancestor that was exactly the same as the previous, but ONE thing was different. You don’t expect them to have 8 limbs like a spider or crab or to find evidence that your ancestory lived in a shell, like a snail. You expect them to have exactly the same features with only slight variations, precisely because science is all about reasonable conservative expectations.
And it turns out, as you would reasonably expect, that those reasonable conservative expectations based on common-sense observation and simple logic have been verified over and over, millions of times. Geologists are able to determine the age of layers of the earth, paleontologists are able to determine the age of fossilized bones, and biologists are now able to map recovered DNA and detect exactly how many mutations have occurred between a certain generation and our current one. And with all of their factual evidence — factual in the sense that “this fossil is from 180 thousand years ago, this DNA sample is different in 350 places from current DNA” — the goal is to reconstruct the puzzle of ancestry in the most conservatively sensible way possible. (And scientists will debate until the accepted reconstruction is as conservative as possible without leaving out any pieces.)
And that’s all it's about. Reasonable conservative expectations. Of course the most conservative expectation possible would be that your kids look exactly like you, and their kids look exactly like you, and that when you reproduce, you’re passing along a clone of yourself. Obviously that’s not the case. Your kids look different. But in terms of overall human features, they look pretty much the same, and the DNA confirms that — the differences are superficial. But you expect that somewhere along the line, there will be “birth defects” (mutations) and some of those will get passed along. And after many thousands of generations, quite a few of those mutations will have been passed down the family tree in many different directions. Some of those great-great-times-a-thousand-grand-children may decide not to have kids. Many have a small number of kids. But then you get that one line of families who has so many kids generation after generation that they outnumber every other descendant… and pass along a HUGE number of those mutated genes. And suddenly your “family tree” begins looking a lot different.
That’s evolution. That’s all it is.
(Originally posted to my Facebook wall)
