Question: how did life beguin

Ciarán O'Brien answered on 12 Nov 2014:

That’s a tricky question, and there’s more than one theory.

the one that makes most sense right now is that life began in the oceans, which were very different back then (we’re talking billions of years ago). they were full of different chemicals and they were much warmer. they were the perfect place for chemicals to react with each other and form new chemicals.

Eventually something called a lipid bi-layer formed. It’s a like two sheets made of fatty acids that like to form tiny bubbles, and they’re what make the cell membranes of every living thing besides viruses. These little bubbles would provide a shelter from the rest of the oceans for chemistry to happen in much faster without being disrupted, and this is probably how chemicals that could replicate themselves formed, like RNA, which is a much simpler form of DNA.

From there, chemical reactions inside these membranes got more and more complex, until eventually you could call them “alive”. These early cells divided and grew and sometimes just bumped into each other and combined and their chemistry changed a little each time. Eventually, after millions of years, there would have been the first bacteria (or life forms very like bacteria, anyway), not doing much besides growing and dividing.

Much, much later, they’d start coming together and performing different functions for each other, and that’s where the first multi-cellular life forms came from, like sponges and algae. This sort of thing just kept going and getting more and more complicated, and as life moved into different environments it adapted to survive, becoming plants, or animals, or remaining bacteria because nothing survived better in a 300 degree Celsius hot water spring. A few short millions of years ago, life got complicated enough for people like us to appear.

Things have gone downhill since 🙂