Biology: How life on Earth may have started (and perhaps why it could): part 0

Tutoring biology, how life originated is an inevitable question. The tutor offers a point about it.

By the cell theory, which I discussed in yesterday’s post, new life can only result from an organism already alive.

Scientists believe life started on Earth about 3.8 billion years ago. Yet, Earth is believed to be 4.5 billion years old. The implication is that 4 billion years ago there wasn’t life on Earth, but at 3.5 billion years ago there was. Life started – where there was none – at some point.

Increasingly I hear a theory that life arrived here on a meteorite. Some bacteria are incredibly resistant to extreme conditions, and may have survived such a voyage to populate Earth. It’s a plausible idea.

Assuming life did not arrive here, but rather began here spontaneously, the event would have been different from what we expect today. However, the context would have been very different as well, and perhaps that’s the important point.

Scientists seem to agree that, around when life became present on Earth, there was a soup of biological molecules. It may have been shocked by lightning, eventually causing a sustained life reaction.

In such a setting, resources were abundant and there was no competition for them. The proto-entity, no matter how unlikely to survive, would have had time and “food” to sustain itself until it improved.

On Earth today, where life is abundant, so is competition. A weak life form can’t compete with strong ones already established, that have had millions of years to adapt to the conditions here.

Therefore, although life can only come from other life in today’s context, perhaps before there was any life at all, its spontaneous development was much more likely.

Source:

www.bbc.co

hubblesite.org

Mader, Sylvia S. Inquiry into Life, 11th ed. New York: McGraw Hill, 2006.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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