Looking for LUCA – step 7

For Willy the source of life was bacteria with celestial origins. He came to this conclusion as bacterial spores are very resistant to high and low temperatures.  So bacteria could come from space and “ignite” an  evolution  of living organisms on Earth.

  • I have not found info so far that  bacteria came from space
  • but it is known that earth has been showered with complex molecules, like amino acids a and nucleotides landing with e.g. Carbonaceous Chondrite meteors.
  • We know that bacteria could survive the first anaerobic, poisonous and hot earth period. (ed. read below about Looki) We also know that bacteria have an important key role in the development of cells.
    I will share with tyou what I have come to know during my searches.

Content

building blocks from Space

“The idea that primitive life on Earth may have been seeded by a comet or asteroid impact is controversial. Since it was suggested more than 40 years ago, however, increasingly complex organic molecules have been discovered in space. ” (Source: http://physicsworld.com/cws/article/news/2003/aug/11/amino-acid-detected-in-space   )

“For the first time, we have three lines of evidence that together give us confidence these DNA building blocks actually were created in space.” (Source: https://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html   )

Bacteria spore Low earth orbit (LEO) tests

Sveral bacteria (bacillus subtilis, Bacillus thuringiensis, Deinococcus geothermalis, Escherichia coli, Micrococcus luteus and more   have been tested in outer space as can be seen in this (wiki) infogalactic list:

AKINETES – an example
“Akinetes are resting-state cells of cyanobacteria that are produced by certain genera of heterocystous cyanobacteria to survive extreme environmental conditions.”

AKINETES SURVIVAL
“A proportion of the akinete population was able to survive a period of 10 days in LEO (ED. low Earth Orbit) and 28 days in Mars simulated conditions, when the rocks were not subjected to UV radiation. ” (Source:  https://link.springer.com/article/10.1007%2Fs11084-009-9167-4  )

What did Darwin think?

“Probably all the organic beings which have ever lived on this Earth have descended from some primordial form, into which life was first breathed,”
(Source: in the origin of species page 484, Darwin)

“But that primordial form lived and died 4 billion years ago. Its traits — where it lived, what it ate, how it survived the brutal conditions on early Earth — are obscured by time and a scant fossil record.” (Source : https://www.washingtonpost.com )

Looking for LUCA,  our  Last Universal Common Ancestor

Newly discovered ‘missing link’ shows how humans could evolve from single-celled organisms https://www.washingtonpost.com/news/speaking-of-science/wp/2015/05/06/newly-discovered-missing-link-called-loki-ties-us-to-our-single-celled-ancestors/?tid=a_inl&utm_term=.b8561c22fbe2

How humans could evolve from single-celled organisms

Newly discovered ‘missing link’ shows how humans could evolve from single-celled organisms

Endosymbiosis – The prevailing theory
the prevailing theory is endosymbiosis, that complex life emerged vis a vis a symbiotic relationship between an archaea organism and a bacterial organism. This is how it can have occured.

“many components that underpin eukaryote-specific features (ed. cell nucleus) were already present in that ancestor.” (Source: https://www.nature.com/nature/journal/v521/n7551/full/nature14447.html )

Step 1. The procaryote ancestor cell (without cell nucleus) developed first a membrane protecting the DNA,   a cell nucleus. However “The origin of the eukaryotic cell remains one of the most contentious puzzles in modern biology. ”

Step 2. An archaea eucaryote cell (ed. a looki ancestor) engulfed a bacteria. And the engulfed bacteria came to work as and be  a mitochondrion taking care of the mother cells sugar methabolism.  When the mother  cell then duplicates, also the mithocondria with its RNA (bacteria DNA) duplicates.  Remind that  the mithocondria RNA is inherited only from female to female.

Below is an image that illustrates the two steps in the endosymbiosis.

https://www.washingtonpost.com/news/speaking-of-science/wp/2015/05/06/newly-discovered-missing-link-called-loki-ties-us-to-our-single-celled-ancestors/?tid=a_inl&utm_term=.58e17de30760

(Source:   https://girlmeetsbiochemistry.wordpress.com/2013/04/06/endosymbiotic-theory/   )

 

Looki (Lokiarchaeota) was found near a hydrothermal vent field along the Arctic Mid-Ocean Ridge a mile and a half below the surface

Source: www.washingtonpost.com  )

 

 

 

Published in: on October 20, 2017 at 11:38 pm  Leave a Comment  

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