We are all equals (I'm not)!


Hopefully, you'll stick with me to the end of this blog-post to discover the meaning of the title. :-) I promise to keep it short.

This post is about “genetic variations over generations”.

I did some research and I found there's a ton of material available. My efforts to understand reproduction, are very partial and it would be arrogant for me to call myself 'an expert'. I'm not. I hardly understand it, but it's incredibly interesting all the same!

For instance... meiosis. This is the first step in the reproductive process. The chromosomes in the individual come together, the chromosomes interchange DNA and then separate to form ova (if the individual is female) or sperms (in males). This is the reason why the traits of the grandparents are visible in the grandchildren!

“Genetic variation” occurs during meiosis; the biochemical process is not perfect. Anything can happen; DNA can be duplicated, deleted or changed! This doesn't represent a problem. Some species have 300 thousand ova in the average female and 250 million sperms in the average male. If a copy turns out bad... it is either discarded or it can't compete with the healthy ova and sperms.

DNA is a complex molecule that expresses a genetic computer-like code. Computers use binary code to program 'everything' the computer does! The DNA does the same thing. If you're a computer programmer, I recommend the page maintained by Bert Hubert. Instead of a binary code with only two options, DNA has four options. A computer 'byte' is 8 'bits' long, while a genetic 'codon' is only 3 letters long.

The next step in reproduction is the union of one ovum with one sperm cell to create a new individual. As noted above; one out of 300.000 genetically different ova blends with one out of 250.000.000 genetically different sperms. This individual has a one in 75 trillion chance to have it's specific unique gene-set (see a similar calculation here - thanks @Dragonblaze)

This will result in the next generation. Two parents have offspring that's genetically different, thanks to meiosis. In a way, it is genetic lovemaking of the grandparents...

Normally, in nature, the next generation contains loads of individuals. Horses only have one foal per year. Dogs may have a litter of 8 pups. A tree can have thousands of seeds. This inevitably means that not all individuals can survive. Exponential growth of one breed is checked by the death of a great number of individuals. All the food we eat, was once a living organism; either plant or beast.

The survivors are the lucky ones, but also the healthy ones and the 'best' ones. When thousands of turtles hatch all at the same time, and hundreds are eaten before reaching the sea... those that make it are the lucky ones. Those that survive and become adults have proven their worth. They can pass their genetic information to the next generation.

Going backwards in time, it seems logical to think that each and every parent generation was the result of their parents reproducing. That is; you have parents, your parents had parents, repeat.

When does it stop?

To me, it seems daft to think that this would ever stop. Parents, had parents, had parents, had parents. Each generation, genetically speaking, slightly different from the previous one.

These slight genetic variations accumulate over time and become big genetic variations, still further in time these variations accumulate and become huge genetic variations. Each adult parent having shown his/her worth in the world they lived in at that time.

We are all equals.
To biologists, evolution started before or during the formation of the very first living cells, 3,9 billion years ago. We are related to each and every living organism on earth through our RNA/DNA. We are equals because we share that extraordinary molecule with all life. We are also equals, because we are alive together with other lifeforms that have 'evolved' the same amount of time as we have.

I'm not!
'My' genetic make-up is similar to all other humans in 99,5% however 'my' DNA is unique. Yours is as well.

Update: Minor corrections thanks @TakeThatDarwin

Evolution as a fact: Genetic variation over generations. (see also berkeley)
Evolution as a theory: Natural selection and Genetic drift. (see also berkeley)

Also check-out this excellent site talkorigins.org for more information.

The great ape question:
"If evolution is true, why are there still apes?"

The answer is really simple. We're distant cousins. We share a common ancestor with other great apes.

Let me give you an example. My great uncle went to Australia in the sixties. As far as I know, his family is doing fine. When his children were born, nothing happened to the children of my grandfather (my mother and her siblings). When his grandchildren were born, this didn't affect me in the slightest.

That's what happens during evolution. Families drift apart and become independent species over time. It doesn't have to be an ocean :-) The bonobos and the chimpanzees were separated by the Congo river about two million years ago.

Micro/Macro evolution:
My friend Kaimatai has written about it. He has a PhD in biology. Nuf said.

Change over time:
When I studied evolution as part of the standard Dutch curriculum, the teacher explained it as being 'change over time'. This is unfortunate, as it's difficult to interpret. What change? Which amount of time?

"I haven't grown wings during my lifetime" is a typical strawman logical fallacy that can only be attributed to this phrase.

Charles Darwin, in his book "On the origin of species" doesn't use this phrase. He talks about accumulative variation over generations in a geological time frame. He lived before genetics had been discovered.

Intelligent design:
Somebody told me the 'language' points at Intelligent Design. However, ID requires a goal, while all the non-coding DNA is pointless if there's an intelligent designer. ID doesn't explain the Golden Mole (an animal with eye sockets but non-functional eyes) or the blind spot in vertebrate (human) eyes, or ...

"4 bases pairs. 20 amino acids. It [DNA] was originally thought to be "too dumb" to be molecule of inheritance" Kaimatai

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