Origins : The emergence and early evolution of life

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One of the reasons to study biological diversity is to answer, at least a little bit, the biggest question of them all - where did we come from? In this section, we'll trace backwards down the tree of life, starting with the last common ancestor.

Because we have access to modern living things, and traces of previous living things (fossils), we can infer a lot about this last common ancestor using the phylogenetic approach we've used all semester long. Even so, there is already some real uncertainty about this creature.

Before the last common ancestor, we're working mainly by conjecture. It should be absolutely clear that at this point, we largely leave the realm of real science here, because the notions we're going to be talking about in this chapter are, for the most part, both unverifiable and unfalsifiable. At least for now. And so, for the record,...

How did life originate, and what was it like before the last common ancestor?.

we don't know

The rest is handwaving - but it's interesting hand-waving, and it's the last day of class, so let's forge ahead.