Science Draak

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Humans, we’re totally bananas (part 2)

May 10

Posted by E Leegstra in Evolution | No Comments

In the last part, I explained how virology can provide evidence for the common ancestry between chimps and humans.

ATCGDNA is interesting, and there’s a lot of it as well. An average human cell contains a bunch of chromosomes which in turn contain our genes. And those genes are made up of four base-pairs. A, T, C and G. And genes are cool, they can define a lot of things, from our eye color, to the size of a toenail and the length of your fingers. They basically define our body and the function of the cells within it.

It is then, not hard to understand that scientists are looking at genes for a lot of the humans traits and also a lot of problems and diseases. A mutated gene could be the cause for a problematic sickness, but also an interesting change, a new trait or a possible removal of an old one.

Genes can say a lot about an organism, and it can be used to explain the differences (or similarities) between two different organisms.
Even if you don’t know much of how genes function or work, you can already play a small mind game to get an idea of it.

 

flower Let’s say we compare a human to a flower. You will notice (obviously), that we don’t have a lot in common with flowers, a flower has no ears and no eyes for instance. Even without knowing what genes a flower has, we can guess that there are probably no genes for ears and no eyes, and if there somehow are, there’s a very high chance that they won’t be close to our own genes.

 

large_BIG CAT FOUND Lets take it a step closer to home. Think of a cat for instance. It does have ears and eyes, and it also has a long tail, and it has claws, something we don’t have like that, but we do have nails.
If we think about it, can we assume that there are more similarities between a cat and a human, than between a human and a flower?

chimp Another step closer, and we can start focusing on Chimps and Humans. We can find differences between chimps and humans. One of those (obviously) is that they don’t have as much intelligence as us. Another few differences would be the long hair, their slightly smaller size, different posture and amount of body hair. You can safely say that there are differences. But there are similarities as well. Chimps have different eye colors, they have facial expression. They have nimble fingers and thumbs. They can use tools and walk up straight.

Would you say that a Human has more in common with a chimp than with a cat? Or with a flower? I’d say yes, but of course this could all be a coincidence. This might all mean nothing, it might actually be that chimps simply evolved “similar” attributes but are different genetically. We wouldn’t know for sure unless we actually dig into the genetic details.

 

So let’s do that. Of course it’ll be impossible to look into all of the chimps DNA as compared to our own, but we can take in some of the broader details and zoom in on a few specifics.
For those who like to look for extra information, know that there are different methods of comparing DNA of one species to another, and these different methods also get slightly different results. So if you look for chimps compared to humans, you’ll find that the range of (similarity) usually lays between 95 and 99% depending on the method used to compare. I’ll explain a little bit more about the details of why these results are different, at the end of the article.

Human vs chimp chromosomesOne of the main points brought up and used “against” the notion that humans and chimps share a common ancestor, is actually one of it’s main strengths , as it shows the process of evolutionary change beautifully.
At first it was thought that humans and chimps didn’t share a common ancestor, partially because of the differences in chromosomes. Humans have only 23 pairs. Chimps have 24 pairs. The situation was obvious, if chimps have 24 pairs, then they obviously are very different from humans, the chromosome count is different.
Imagine the shock when scientists discovered that one of the humans chromosomes is actually the same as two of the chimps chromosomes, but fused.

Scientists then started looking deeper in on the situation, comparing the fused chromosome to the two human non fused chromosomes, and what they found, was that the fused chromosome nearly exactly matched the human’s, when combined.human vs chimp chromosome

The picture to the right shows a comparison of a human and chimp chromosome comparison. The lines in between point out the similarities.

You can click on both pictures to show an enlarged version of them.

You can easily see the similarities and the differences, evidence for the common ancestry of chimps and humans. There are of course more pieces of evidence in the puzzle, these are just two (but strong ones) in the big puzzle of life and the history of the world.

As a final note, I’d like to shed some light on some of the confusing details about the different percentages of similarity between humans and chimps which I hinted at earlier. I’ll explain it by example.
 
Let’s say you have a gene for eye color, and this gene has 100 base pairs. Look at a chimp. A chimp has eyes, but how do they compare to a humans eyes?. This chimp might have a gene that works in the same way as the human one does, but 7 of the 100 base pairs are either in a different position, or are different in general (missing, added, deleted, etc through evolution). This would mean that even though the overall function of the gene is the same and we can say it is comparable to that of humans. There is still a 7% difference in the actual base pairs.

On a larger scale, this would mean that if you look at genes, you would find a lot of similarities, and you need to build up a comparison based on those function similarities in combination with the base pair similarities. An octopus for instance, also has eyes, but it is a lot more different genetically, even in those functions that look a lot like our own.

I’ll finish this article with two articles on chimps and behavior, drawing another link that is definitely interesting.

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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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Why have I been so slow with the updates?

Apr 23

Posted by E Leegstra in News | No Comments

Before, I had promised myself and whoever reads this site, that I was going to update frequently. Giving small and large bits of information on various topics. A couple of people have requested specific information on various topics.

And the only thing I can answer to those, is that they’re in the works. I have multiple posts that I’m working on and filling up with information to explain them.

But about a month ago, my life has gotten a few changes. I got a nice irregular timed job, which still has me trying to adapt to it a bit. On top of that, I became a scout leader and it has taken a bit of getting used to as well.

All in all, I faced off against less time to write and when I did have some free time, I found that I was either not motivated enough, or simply too tired to really do much writing.
I’m trying to change this, and I hope that with my (hopefully) soon to arrive Open Pandora, I will have a means of writing while I’m away from my home computer.

Sure sure, it’s a laptop, but it’s still a heavy one, and it’s not the easiest thing to carry around. The Pandora would be an ideal solution for me in this case.

 

On a whole different note, I’m thinking about changing the whole look of the site. I like it as it is, but I feel I can do more with it. Same with the structure of links and topics (which are both kind of nonexistent at this point). I’m thinking about setting up a main news page, and set up a sort of hierarchy with the topics I write about, setting them up in levels. 1 being the easiest level, with basic information that everyone should understand. 2 a little harder and three the hardest. I plan on making level three the kind of explanations that would require at least the basic knowledge found in level 1 and slightly more advanced knowledge found in level 2.

But that’s just an idea still, I haven’t decided upon anything yet. What do you guys think?

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Degeneration, the end of evolutionary theory.

Feb 11

Posted by E Leegstra in Book Reviews | 2 Comments

And a scientific alternative.

A scan of the book

I found this book in the library by chance, I was looking for some books on geology but instead stumbled upon this little gem. It is written by Peter M. Scheele and it advertises itself as the end of evolutionary theory.

This however, is far from accurate, and the books promotes a lot of misconceptions and false information in order to get its point across. It’s main alternative for instance, is based on two falsehoods.

In this review, I’m going to take a closer look at the two main points the book makes, and how a review of those points shows the problems with the ideas this writer brings forth. Then I will shortly go into detail on the alternative and how, without those two points, the whole alternative is ridiculous, based upon a false premise.

When I quote from the book, I will translate it to English myself (It’s a Dutch book) and try to accurately represent the book. This is a bit of a challenge, because the book is written in a strange way. The author also tries to explain many concepts in an informal way, causing a lot of problems not only for translation but also for the ideas he tries to represent, making it a bit harder to translate. I will do my best though.

I would also like to add that the author seems to have a certain kind of arrogance, when reading this book, you always have the feeling that he feels he’s right, no matter what, and that he’s some kind of self glorified rebel against the system. A sensation that doesn’t exactly make the book more fun to read.

Shall I make a spry remark, one which might just make the news?

The whole problem of missing morals and values in society, and the heavy need for social discussion about this, finds its origin in the acceptance of evolutionary theory. (p.26)

Read the rest of this entry »

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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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