Did life start more than once?

Question

Is there any evidence that life got started more than once on earth?
If you say yes, please be specific and show your source.

Answer 1

No real evidence. All organisms share the same basic biochemical structure, everything from DNA to the respiratory enzymes. That means that if life did start multiple times apparently only one lineage survived.

Some scientists have suggested that the existence of both RNA and DNA is indicative of two parallel events leading to life late in the development of complex organic polymers. The theory runs that before the development of life proper RNA was essentially a prebiotic 'predator' on other complex organic molecules, while DNA was in turn a "predator" on RNA. Life as we now know it is theorised to have developed from an agglomeration of early RNA life and early DNA life. Of course there is no evidence for this, but it does explain some of the observed data.

Answer 2

Let's say for the sake of the argument that we define life as having started when the first DNA-molecule was formed. And let's say that DNA was formed either by an uncatalyzed reation between ribose and a nucleotide or it was catalyzed by some inorganic catalyst.

Under those assumtions, you asked four questions:
- Was there only one DNA-chain that formed in this way?
- If so, did all the, say, adenines in this chain arise as copies of the same ancestral base?
- If so, do all the four bases have a common ancestor?
- Did all the ribose links have a common ancestor?
Add to this the questions if the formation of the first RNA was catalyzed by the first DNA or if it has an independent origin. And the same questions for cell membranes, ribosomes and golgi apparatus.

So even if we can agree on a very specific model for the origin of life and a very specific difinition of what life is, the answer will still be complex. Some of the components of life may only have formed once. Some may have formed billions of times but all except one of became extinct. And for some components, multiple ancestors may still be present in the genomes and/or cellular organels of living organisms today.

Answer 3

Life starts only once, when lightning zapped the soup of life and created simple proteins and glucoses, all basics of DNA and life. Well, when those have created life, yes, the rest is history. But then, that is only with a zap, what happens when they were more than one zap? Those extra zaps could've created more life too. But chances are they all evolved to be the same thing anyway because the soup of life only exist at a period of time where basic elements of life are mixed together at the early stages of earth.

Other than that, no idea.

Answer 4

Just as it is currently impossible to provide undisputed proof of how life started, so too is it impossible to show that it didn't start once before and die off.

Odds are, this will never be known, as the first question is hard enough with even all of data that we can accumulate. I can't imagine how we would somehow find out if life existed before that without finding third party evidence recording it.

And that's about as Star Trek as I get. c-ya!

Answer 5

Life began and then expanded and evolved from that point forward. There once was a time where 60% of all life on the planet died, but those that survived just kept marching along on the same track.

Answer 6

i dont think we can currently prove any of it.

it is all theories.

if life did begin on earth in the primordial ooze and it could start once, it is a good question to ask if

a. it was an incredibly rare event and the pre-cursors to life only once developed into life
b. under the conditions when it did start, was it happening routinely, like trillions of times, and only one of those time it developed into more organized life
c. has it developed trillions of times, and is it still happening today all the time

there are countless possibilities, i only listed 3 in the interest of brevity, thanks for the good question.

by the way, i think it has started countless times all over the universe, including countless times here on earth, but only very rarely does it survive and develop into a more organized, self sustaining system. and even much more rarely does is develop into bacteria or something analagous to complex organisms like that. and even much more rarely does it develop into higher organisms, expecially ones that can contemplate their own existence.

i also believe that there is more to this puzzle than we know and it is really arrogant to think we know the answer. for example, we called pluto a planet until today, that question is about one millionth as difficult to answer than the origins of life billions of years ago. for us to think that we have it all figured out is really naive.

once again, thanks for the good question

Answer 7

Sure - God created the animals, then created Adam and then created Eve. Not that I believe that crap, but at least it's an answer with a source. Actually, the truth is that there is no way to know based on the knowledge we have right now.

Answer 8

No, no longer fairly. you do not must have sex as a thanks to be sensible or sensible or have a clue about what existence is about. i imagine that the basically issues that replaced after I lost my virginity were that i now understood why human beings have problem controlling themselves and that there is unquestionably a level of no go back at the same time as 2 absolutely everyone is taking section in round. in the different case, the very undeniable actuality that you're nevertheless a virgin in this style of existence of ours exhibits me that you're a mature and strong lady. sturdy for you! i desire it may prevent your self for marriage (I did and that is fairly worth each and each of the disappointment, believe me!) and discover an excellent guy to marry.

Answer 9

No. Bacteria were the first forms of life, then they mutated and evolved from prokaryotic to eukaryotic, and the rest is history.

Answer 10

Witness the billons on the planet ;) j/k
Dinos & the asteroid ?
Ice Age?