4. Molecular Genetics I

Stanford University.

So we pick up from whatever the last day was.

And we do our first disciplinary leap

as promised at the very beginning of the course.

The entire function of the first half of the course

is to leap from one bucket to another, such that

just as soon as you feel like you are getting mildly

comfortable in one, we will spend time

trashing it from the standpoint of a different discipline.

This is our first one of these.

And the whole point of this jump is to show on a certain level

exactly where one discipline's the notion of an explanation

ends, another one begins.

And what this one will be about is how evolution works down

on a molecular level.

Where did we leave off after finishing our overview

of the evolution of behavior?

We finished with a bunch of criticisms at the end.

Criticizing sort of what some of the basic tenets

were of that view.

First off, that notion of heritability.

Heritability-- assuming that all sorts of behaviors

have a genetic component, have a genetic basis,

have a genetic cause.

And we will see those are worlds of differences in those words

there.

And what we saw was that that could be the case.

That could not be the case.

That's going to be what we focus on a great deal today.

Another one of the basic tenets--

this notion of adaptation.

Everything you see is wonderfully adaptive.

The outcome is exactly the process

that evolution brings about to optimize results.

The counter view being the world of spandrels-- a lot

of the time, stuff gets carried along as baggage.

Things evolving aren't necessarily things

that have been sculpted into being as adaptive as possible.

Another critique, and one that's also central today,