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Humans, we’re totally bananas (part 1)

May 3

Posted by E Leegstra in Science explained | No Comments

Or so that is what the results of many studies, fossil finds and genetic research might make us believe. We are genetic brothers and share an ancestor with the chimps.

But how did we come to this conclusion, why do scientists accept this explanation of humanities history?
Many reasons actually, there’s a lot of evidence coming in from genetics, paleontology, virology, geology and more. I’m going to focus and explain two of these evidences, namely:

Virology: How the existence of viruses in different species, is evidence for their shared ancestry.

Genetics: Many different species have different genetic setups. The basic building blocks are the same but there are usually a lot of difference beyond that. Chimps and humans share a genetic make up that is suspiciously alike though.

After some though, I’m going to release this in two parts one. Part one for the virology part of things, and part two for the genetics side (which is a lot more information, and doing it all in one article is a bit much)
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Let’s start of with virology, the study of viruses. We’re talking about endogenous viruses in this case specifically. And these are viruses that plant themselves in someone’s reproductive cells, the so called germ line cells.

For those of you who don’t know how viruses work (basically), a short introduction.

All living things have cells, you are living, so you have them as well. These cells are basically your body, billions and trillions of them together, groups of them with different functions (muscles, bone, intestines, brain, etc) form your body and its functions.

Within these cells is the core, of course there’s more in a cell then just a core, but the core is important right now, because the core contains the cells DNA, the so called building blocks of life as we know it.

Bacteria’s, fungi, yeast form all kinds of infections that work their magic outside of your cells, they infect your blood stream and use various methods to hurt your cells from the outside. Viruses on the other hand, work differently.

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A retrovirus is basically like a package, a package, which in this case, contains a string of RNA. The virus package finds a cell and literally injects the RNA into it. This RNA then triggers the production of a DNA copy of itself (RNA and DNA are closely related) which then inserts itself into the DNA of the host cell. This, in most cases triggers the cell to make RNA clones of the original Retrovirus, allowing the virus to multiply and eventually infect new cells through the same method.

Some though, don’t activate, and you could say they simply piggy back ride in the cell. They latch onto the DNA of the cell, insert themselves and then just sit there. The cell resumes its normal functions and when it goes through the process of Mitosis, reproducing itself in the process, it makes a copy with the added DNA from the virus.

Imagine this in a cell that is used for reproduction, you could get this virus spreading through the offspring, and then their offspring, and so on, so on. You’d have a whole generation that would contain this virus DNA in their own DNA.

And this is where it gets interesting. Imagine you find someone you don’t know, but when you genetically test him and yourself, you find that you have an ERV (Endogenous Retro Virus) at point C in your DNA. And this person, happens to have the same ERV also at point C in his DNA. You could then say that there is a very very high chance of him and you being related and having a common ancestor. This ancestor, at some point got this ERV infection and passed it on to his/her children. The below diagram shows how this works, where you have an Ancestor and various generations of offspring.

Diagram virus mitoseSounds pretty logical, right? Well, we can take this a step further. What if we didn’t just find ERVs in people, but we find ERVs in chimps as well, and those ERV’s are at the exact same point in their DNA (point E this time) as they are in humans (also point E), wouldn’t it then be logical to say that this is pretty strong evidence for them sharing a common ancestor?

The other option, that the “same” retrovirus attached itself at the “same” exact point in the DNA of two different hosts (one chimp ancestor and one human ancestor) is so small, it nears impossible. Viruses often have a specific host range, cells they can and can’t infect. But the insertion into the DNA doesn’t have a specific range. Making it near impossible that two separate injections end up injecting the same virus at the same point in the DNA.

And that is how the existence of viruses in different species can provide evidence for a common ancestor. Next up, genetics!

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Evolution. A theory and a fact?

Feb 10

Posted by E Leegstra in Science explained | No Comments

 Questionmark

In a previous post HERE, the principles behind a scientific theory rae explained and the differences between a scientific and personal theory were pointed out.

Many sources say that Evolution is both a theory, and a fact, and this might be confusing. How can something be a fact and not a fact and a theory at the same time?

It should be pointed out that the theory of evolution and the fact of evolution are actually two separate understandings that simply carry the same name. They are separate, but one (the theory) describes how the other (the fact) works.

It works like this:

Facts are found all over the world. In a way, you could call these facts the observations we find in our search for knowledge. A simple way to look at it, is to look outside and say “grass grows, it’s a fact” and in normal circumstances you would be right, grass does grow. But how and why does it grow?

This is where a theory comes in handy, it tries to explain the fact, the observations. In our grass analogy, it could explain the inner workings off the grass, making the conclusion (it grows) a fact supported by a theory.
In a way, you could call it grass growing theory.

Same with evolutionary theory and fact. There is a series of facts, facts which were first put together by Darwin, he than explained these facts. At some point the facts were called evolution. And the theory of evolution, explains how it works.
One understands of course, that as more and more observations are made on the topic of evolution. The theory adapts, because it has to explain it all as accurately as possible.

An example to clear this up. If we just made a  theory on how grass works. But we never knew grass had roots. Then finding grass roots, would give us new observations, a new fact that hasn’t been explained by our “grass theory”. In other words, we have to change our theory so that it explains grass, including the grass roots, and we have to do so, in a way that both get explained.

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What is a theory?

Feb 1

Posted by E Leegstra in Science explained | No Comments

QuestionmarkA theory is basically the ability to explain a phenomenon. There are  two uses of the word theory. One is a personal use of the word, something you find in every day life. The second is the scientific use, which is a bit different and less known outside of the scientific circles.

When we think up ideas to explain some phenomenon we encounter, we will make up a theory that can explain it. Usually, this means, guessing a bit, sometimes by using some of the surrounding evidence to support our guess.
For example. If we find a tree that had fallen on the road, we could guess that it might have been cut down. Or perhaps it was broken by a storm. We could use what we know and see, to make a guess (or multiple) to the reasons of the tree being on the road. This means we’re basically making theories on that specific phenomenon.

This is a personal use of the word theory. Any one of the theories could be right or wrong.

In science, the word theory is something different. In science, a theory has little to do with guesses, and more with accumulated evidence.
A scientific theory is still an explanation for a phenomenon. But it’s an explanation that has accumulated so much evidence supporting it, that the chance of that explanation being wrong, is really small.
On top of that, the evidence that is gathered, is repeatable, consists of experiments or data that can be repeated and rechecked as needed, thus building a solid base of support for the explanation.

If one were to do a lab test, and would repeat that same test 1000 times. One would get 1000 results of that specific lab tests. If 980 out of those 1000 results point to the same result. One can say that this result is very solid. One can say that doing the test another time is probably going to end up with the same result, with a very low chance of the result being different.

This is, in simple words, how theories function. You have a lot of data, from many different fields of science (biology, paleontology, etc) that all support the scientific theory of evolution.

Thus, the chance of a new piece of data, a new result, a new piece of information, coming along and being different, is nearly zero.
There’s more to it than that of course. Because even though the whole theory is a sturdy mass of evidence, it doesn’t mean that small parts of it aren’t revised if more accurate information comes along.
A way to look at it. Is like looking at a really complicated tree. It has branches all the way up, that we still haven’t discovered, that tell us things about the tree. But whatever we find, the tree is still a tree. It won’t change the tree. It’ll only change our understanding of those branches and how the fit with the tree.

There’s one more factor that makes a scientific theory different from a personal one. And that is the power to make predictions.

Based on information that has been gathered before. Predictions can be made about more information that is found.

Predictions are a powerful tool, because they help validate the theory in two ways:

1. If information is found that doesn’t follow the prediction, than the prediction and the explanation it is based on, obviously has errors and the explanation can be changed and edited to make it more accurate.

2. If the prediction does hold ground, it’s a validation of the strength of the theory.

And that is the difference between a scientific theory and a personal theory.Keep in mind, that this means that when a scientist (or anyone) uses the word theory. It doesn’t automatically make it a scientific topic

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