Sunday, June 21, 2009

Evolution 2

"On behalf of all organisms that have ever lived: not a single one of our ancestors died before they reached adulthood and begot at least one child. In a world where most organisms die before they can procreate, descendants are common but ancestors are rare. But we can all claim an unbroken chain of successful ancestors all the way back to the first single-celled organism."

The matrilineal nearest common ancestor to all of humanity is the Mitochondrial Eve. In other words when you trace back all of the females who ever lived from there mothers to their grandmothers and so on. In short all living humans today are related to this one person by at least one parent. This was done using a process of tracing the human lineage back words through mitochondrial pathways. Now this is not to say that the Mitochondrial Eve was the only female of her era. She lived among an entire population of males and females but she is special because only her ancestors survived until now. Now the Mitochondrial Eve is also not our most recent common ancestor but only the matrilineal nearest common ancestor.
"The MRCA answers the question, "Do any of my four grandparents overlap with any of your four grandparents? If not, then do any of my 8 great grandparents overlap with any of your 8 great grandparents?" Between one-hundred and two-hundred generations back, a single person will appear in every living person's family tree. However, each person has only one mitochondrial ancestor with each generation backwards because each person inherits their mitochondria from their mother. The question of "when did Mitochondrial Eve live?" is answering the question of "When does my mother's mother's mother ... overlap with everyone else's mother's mother's mother ... (all the way up the female lineage)?"
Since we are all born with Mitochondria from our mothers Scientist need only to trace this Mitochondria back til they reached Mitochondrial Eve.

This Mitochondrial Eve is believed to have lived 170,000 years ago in Africa. She was an anatomically modern Homo Sapien and lived in a time before humans began to migrate out of Africa and into the rest of the world.

Y chromosomal Adam is an entirely different story. Now Y chromosomal Adam and Mitochondrial Eve lived at entirely different times. Adam was an african man who lived 60,000 years ago.

"By analyzing the Y-chromosome DNA from males in all regions of the world, geneticist Spencer Wells has concluded that all humans alive today are patrilinealy descended from a single man."

Y chromosomal Adam is the only man from his time to have a single unbroken family line to modern day similarly to Eve their contemporaries had family lines that would eventually end.

It's kinda interesting that not relatively not that long ago all of our common ancestors lived in Africa not knowing that their family lines would continue for so many generations. Even still this is only the tip of ice burg when compared to the Universal common ancestor who is in other words every living creature on earths ancestor.

Friday, June 19, 2009

Evolution 1

"And lastly, a thought for the right-wingers out there: At some point half of you was an egg in your Mother’s womb. That egg existed in her body from the day she was born. And a long, long time ago, she too was an egg in her Mother’s womb, who had that egg ready for use from the moment she squirmed out of your Great Grandma’s nethers. The point being, technically speaking, there’s no break in the chain of existence, no time when you are not a life form of at least the most rudimentary sort. Your family, at least on your Mother’s side, could theoretically be considered an immortal, constantly-regenerating organism. Of course that would make men, whose sperm has to be created years after the moment of birth, just disposable donors here to fuel the everlasting fire of womanhood. You go girls!"

I'm always amazed when I think about life and the beginnings of where us as a species and us inhabitants of earth originated. From my limited knowledge all human life originates from one person who lived thousands of years ago who evolved from a proto species of ape who evolved from a proto species of mammal who evolved from a proto species of fish who evolved from a single celled organism that evolved out of amino acids creating chemical reactions in the primordial soup 3.5 billions of years ago. This all not being possible without the help of water. There are many theories on where water on earth originated I dont know which ones are the most trusted. It seems all we can do is speculate for now. According to wikipedia the main theories are-
* The cooling of the primordial Earth to the point where the outgassed volatile components were held in an atmosphere of sufficient pressure for the stabilization and retention of liquid water.
* Comets, trans-Neptunian objects or water-rich meteorites (protoplanets) from the outer reaches of the asteroid belt colliding with a pre-historic Earth may have brought water to the world's oceans. Measurements of the ratio of the hydrogen isotopes deuterium and protium point to asteroids, since similar percentage impurities in carbon-rich chondrites were found to oceanic water, whereas previous measurement of the isotopes' concentrations in comets and trans-Neptunian objects correspond only slightly to water on the earth.
* Biochemically through mineralization and photosynthesis (guttation, transpiration).
* Gradual leakage of water stored in hydrous minerals of the Earth's rocks.
* Photolysis: radiation can break down chemical bonds on the surface.

I kinda like the comet one but that's just me. Now all life came from single celled microbe like organisms in water which wouldnt be here without the planet earth itself.

The planet earth originated when our solar system (which was comprised of a cloud of dust and gas spiraling around in a giant disk shape) began to spin at such a rate that all the mass contained within collected in the middle of this giant disk. sort of like when you toss a penny into those spirally things. I have no idea what they are called but you get the idea. all of this mass began to heat up because of moving so rapidly and started to form proto planets from the debris of the crushing mass. all of this matter heating up in the center had no where to go and was getting extremely hot. "nuclear fusion of hydrogen into helium began, and eventually, after contraction, a T Tauri star ignited to create the Sun." 4.54 billion years ago our planet was born.

Now all of this planet making business came about because of the debris left over from the big bang the start of the entire story of all of our lives.

In conclusion, every single person place thing constalation planet star gas or microbe originated from the same source. We are all connected, we are all one being one organism one life. I find it fascinating.