In the news today was a story about DNA components being found in meteorites. What is the more likely interpretation of the implications of the discovery? That:
1. The molecules that were contained in the meteorites allowed life to spontaneously arise on earth,
2. Life spontaneously arose in the meteorites while in space and was deposited on earth,
3. Living DNA-based organisms were already present when the meteorites were formed and were then deposited on the earth, or
4. Insert your theory here.
Scientists whn are adamant that life somehow arose during a freakish confluence of ideal conditions tend to support 1 and 2. In my view, the evidence so far is that only life begets life.
What say you?
1. The molecules that were contained in the meteorites allowed life to spontaneously arise on earth,
2. Life spontaneously arose in the meteorites while in space and was deposited on earth,
3. Living DNA-based organisms were already present when the meteorites were formed and were then deposited on the earth, or
4. Insert your theory here.
Scientists whn are adamant that life somehow arose during a freakish confluence of ideal conditions tend to support 1 and 2. In my view, the evidence so far is that only life begets life.
What say you?
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Here's an article you may enjoy, though some of the language can be technical:
http://www.newscientist.com/article/mg21…
Even if the pangenesis theory is right and the origins of life on Earth are extraterrestrial, it still doesn't answer how life occurred in the first place.
When it comes to the machinery, RNA world is by far the most popular theory today.
However, forming stable cell membranes are also very important (and why the "primordial soup" is almost certainly wrong). My favorite theory addressing this is alkaline vents, which is basically permeable rock that forms a membrane (link). Others I've seen include clay vesicles and mica sheets. Cold origins of life also means picking a stable membrane is not as critical.
http://www.nature.com/scitable/topicpage…
http://www.newscientist.com/article/mg21…
Even if the pangenesis theory is right and the origins of life on Earth are extraterrestrial, it still doesn't answer how life occurred in the first place.
When it comes to the machinery, RNA world is by far the most popular theory today.
However, forming stable cell membranes are also very important (and why the "primordial soup" is almost certainly wrong). My favorite theory addressing this is alkaline vents, which is basically permeable rock that forms a membrane (link). Others I've seen include clay vesicles and mica sheets. Cold origins of life also means picking a stable membrane is not as critical.
http://www.nature.com/scitable/topicpage…
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2 and 3 are definitely wrong. 1 probably is partially true but is vague and subject to conflicting interpretations.
The fact that life arose on earth very soon after conditions for life became favorable suggests that those conditions were not a "freakish confluence of ideal conditions." The earth is 4.55 billion years old. The end of the second cometary bombardment about 3.8 billion years ago allowed the earth's surface to cool down, and that is when life appeared.
Only life begets life nowadays because the conditions for abiogenesis no longer exist. And if through some feakish accident a new life form did appear now, it would soon be consumed or out-competed by existing life forms.
The fact that life arose on earth very soon after conditions for life became favorable suggests that those conditions were not a "freakish confluence of ideal conditions." The earth is 4.55 billion years old. The end of the second cometary bombardment about 3.8 billion years ago allowed the earth's surface to cool down, and that is when life appeared.
Only life begets life nowadays because the conditions for abiogenesis no longer exist. And if through some feakish accident a new life form did appear now, it would soon be consumed or out-competed by existing life forms.
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All the answers are far-fetched but are common explanations in evolution