I was watching a new BBC programme called Earth: The Power of the Planet and it said that the earliest lifeforms to come into existence were single-celled bacteria called stagocytes (?). Are they our ultimate ancestors in evolutionary terms or were there other, subsequent instances of new lifeforms coming into being?
In other words, was life sparked more than once?
2007-11-22 14:08:55 · 5 answers · asked by celtish 3 in Science & Mathematics ➔ Biology
Sorry, for "stagocytes" read "stromatalytes"
2007-11-25 07:07:30 · update #1
It is quite possible that life was initiated more than once.
However, it is most likely that all existing organisms derive from only one such initial lifeform.
We can be pretty sure of this because *all* life on earth uses exactly the same genetic code: for example, the codon GUU codes for the amino acid Valine in *all* organisms, and never anything else. This is almost certainly because we all evolved from some primordial organism that used that particular code. Similarly, we all use the same 4 nucleotides in our DNA, the same 4 nucleotides in our RNA, and the same 20 amino acids. Not any different ones.
2007-11-22 22:47:16 · answer #1 · answered by gribbling 7 · 2⤊ 0⤋
No one really knows for sure.In evolutionary terms,the furthest you can go back is a population of theoretical organisms that are sometimes called luca(last universal common ancestor).But as far as we can tell,it looks like some replicator could have been sufficient to have produced all living things.It looks like we are getting pretty darn close to creating a life form from scratch too.I'll leave you with a link.
2007-11-22 14:23:38 · answer #2 · answered by vibratorrepairman 3 · 2⤊ 0⤋
This is the type of post that there is no exact reply to. The reason I'm saying this is because every time a cell divides a new life is beginning; an evolution that has been going on for eons and eons.
2007-11-22 14:19:16 · answer #3 · answered by Anonymous · 2⤊ 0⤋
If life precursors were less complex than stagocytes, then they would be food. We do not know if life tries to arise anew now, but we do know that microorganisms are everywhere and hungry.
2007-11-22 14:18:43 · answer #4 · answered by Anonymous · 1⤊ 0⤋
It is highly probable that there were many
starts and false starts before life succeeded
in becoming self sustaining.
2007-11-22 15:02:00 · answer #5 · answered by Irv S 7 · 2⤊ 0⤋