Uncovering Unknowns in the Evolution Timeline

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Discussion Overview

The discussion centers on the current unknowns in the evolution timeline, particularly focusing on the transition from amino acids to proteins and the origins of life. Participants explore various theories related to prebiotic chemistry and the mechanisms that may have led to the formation of early biological molecules.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that the transition from gaslike "soup" to amino acids was influenced by intense lightning and UV radiation, referencing Miller's experiments.
  • Others argue that the lightning hypothesis may not be plausible in prebiotic Earth's atmosphere, suggesting that water vapor, necessary for lightning, was likely produced by life itself.
  • A participant notes that a complete historical record of all life-forms and the full history of evolution may never be attainable.
  • Several scenarios for the origins of life are mentioned, including the self-assembly of organic molecules on clay and chemistry occurring at deep-sea vents.
  • There is a suggestion that the original biomolecule may have been RNA or ribo-proteins, which can replicate and perform catalysis, unlike proteins and DNA.
  • It is noted that amino acids can form proteins without enzymes, but a stable code, possibly RNA, would be necessary for meaningful sequences of amino acids.
  • A participant recommends searching for scientific literature on prebiotic chemistry and the origins of life for further information.

Areas of Agreement / Disagreement

Participants express differing views on the plausibility of various hypotheses regarding the origins of life and the evolution timeline. No consensus is reached on the mechanisms involved or the completeness of the evolutionary record.

Contextual Notes

Some claims depend on specific definitions of life and evolution, and there are unresolved assumptions regarding the conditions of early Earth and the processes that led to the formation of biological molecules.

sean1234
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Where are the current unknowns in the evolution timeline?
It is my knowledge that the progressions from gaslike "soup" to amino acids is believed to have been caused by intense lightning and UV radiation. But the mystery is how we went from amino acid to protein? Are there any other unknowns in this theory.
 
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sean1234 said:
Where are the current unknowns in the evolution timeline?
It is my knowledge that the progressions from gaslike "soup" to amino acids is believed to have been caused by intense lightning and UV radiation. But the mystery is how we went from amino acid to protein? Are there any other unknowns in this theory.


These questions about the origins of life are not part of the theory of evolution. Evolution assumes the ability of organisms capable of reproducing with variation.

There are a number of theories about the origin of life. The lightning explanation was suggested by Miller's early experiment showing that a flask of "chemical soup" could form amino acids under the effect of an electric arc. But the lighning is not thought to have been very probably in prebiotic Earth's atmosphere; life is involved in putting water vapor into the atmosphere which would, at least on simple models, be requied for lightning to form.
 
sean1234 said:
Where are the current unknowns in the evolution timeline?
Are there any other unknowns in this theory.
It depends on what you're asking about.
If you demand, say, a full historical record of all life-forms on Earth, and hence, the complete history of evolution, then that story will never appear.
 
sean1234 said:
Where are the current unknowns in the evolution timeline?
It is my knowledge that the progressions from gaslike "soup" to amino acids is believed to have been caused by intense lightning and UV radiation. But the mystery is how we went from amino acid to protein? Are there any other unknowns in this theory.

You seem to be referring to the Miller Urey experiments.

There are several other scenarios that are possible. One involves self-assemble of organic molecules on a type of clay found near lakes. Another involves chemistry at deep sea vents.

The original bio-molecule was more likely RNA or ribo-proteins (not sure if I nailed that name) --- it can replicate *and* perform catalysis. Protein and DNA each only do one of these, to our knowledge.

Amino acids can be catalyzed to form proteins without the aid of enzymes, but any "meaningful" string of amino acids would need to be directed by a somewhat stable code (RNA).

Also - go to pubmed and search for abstracts using terms like: prebiotic chemistry" "origins of life" etc. You should find lots of reviews and other types of information.
 

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