Last Puzzle is the Life Puzzle

Last Puzzle is the Life Puzzle

I am intrigued by how life evolved on our planet.

I won't exclude the fact that life would have traveled from outer space in a tiny meteorite.

Leave that argument aside for the time being.

How to approach the problem?

Top down approach?

Bottom up approach?

Either way I am going to get bogged down somewhere around one (1) billion years into the past.

The premises are many.

1. Origin of cellular life is incredible.

Almost impossible in a hostile environment.

2. It happened very very slowly.

3. In its progress toward self perpetuation, there were many obstructions including bombardment of meteorites.

4. It went through five mass extinctions.

Currently it is well into its sixth extinction.

5. There could have been half life half chemical scenario.

How the interaction went on we do not know.

6. Cellular life is so labile it does not leave tell tale stories or leave behind markers in stromatolites.

7. Earth is a living planet and it does not have its oldest rocks available for study.

Its oldest rock is only two and a half billion years old.

Earth life of four and a half billion is estimated from meteorites.

There is two billion years of missing history which we have to surmise.

8. In addition there were catastrophes.

9. I am comfortable with the last 500 million years of its evolution of that the last 3 to 5 million is matter of fact biology being unraveled.

10. How could I dissect the first 500 hundred of the last billion years.

11. In addition there are many other questions.

WHEN?

WHERE?

HOW?

Life originated?

12. What was the smallest living particle?

We seem to assume that we know a lot.

On the contrary we know very little.

We are stuck with the hereditary and survival of the fittest scenario that would suit only the last 5 million years, assuming mitochonridal mutations is rare.

In fact, major mitochondrial mutations are very very rare.

It is our energy store.

If it goes haywire life cannot exist in the current oxygen rich planet with cellular life.

This preamble is for further dissection by my friends far and near.

There are number of salient points that were not available to Darwin that cannot be ignored.

They did not come by chance.

My premise is that evolution brought order to the world (universe) without it.
There was economy in participation.
Assimilation of two carbon units, twenty amino acids coded by a few purines and pyrimidines, about 20,000 variants of structural proteins with only levo-rotation (no dextro-rotatoion of sugar molecules) are convincing evidence that it started at one point in modern evolution continued albeit slowly.

But nitty gritty of evolution and diversion of species were determined not by nucleus but by mitochondrial evolution.

Mitochondria were very resistant mutation and they occur once in every 3 to 5 million year intervals.
When that happened drastic changes happened to the primates (erect posture, language acquisition and larger brain) in evolution.
How it happened in ovum is a mystery by all accounts and we do not have mitochondrial data to evaluate.

For example we have giant mitochondria in salivary glands and in yeasts.

Yeast mitochondria can hijack nuclear DNA and that is one way of mitochondrial evolution.
 

 Mitochondria evolved by endosymbiosis.  

Mitochondria originated by a endosymbiotic event when a bacterium was captured by a eukaryotic cell. The organelles have far fewer genes than an independent bacterium, and have lost many of the gene functions that are necessary for independent life (such as metabolic pathways).