- Okay, it's time
to look at some weird examples.
Now, if humans are engaging in--
if humans are creating
the selective pressure,
then it's
considered artificial selection.
Some examples
of artificial selection.
First of all, did you know that
all of these plants are actually
the same species?
Kohlrabi?
Has anyone ever eaten that?
Brussels sprouts?
Okay, first of all,
don't Brussels sprouts make you
think of little cabbages
and don't they kind of taste
like broccoli?
It's because they're
all the same plant.
Cabbages, cauliflowers--
don't cauliflower and
broccoli kind of taste the same?
Broccoli and kale?
All of it is the same plant.
It came from some crazy mustard
plant and then a human was like,
I really want a big stem
from my mustard plant,
and took the seeds
from the bigger stemmed mustards
and then planted those.
And then took
the biggest mustard-stemmed
seeds and planted those.
And from those took the biggest
mustard-stemmed seeds,
you get the idea.
And pretty soon, we
have this incredible diversity
of different broccoli foods
and we made them.
We created that diversity.
Okay, let's talk about the dog.
I mean there's really no words.
What? Clearly there is
no evolutionary advantage for,
pretty much,
any of these things.
They would get absolutely
destroyed in the wild.
This is the wolf from whence
they came and, I mean,
it's pretty unbelievable
how we ended up
with what we ended up
with in the world of doggies.
And that's an example
of artificial selection.
What can I say
about dreadlock dog?
Poor dreadlock dog.
This is a real dog,
and he really has dreadlocks
and that's a species
of dog that we've created
that has all those dreadlocks.
Like, isn't he hot?
I'm sorry dreadlock dog.
That's artificial
selection gone crazy.
Might just get
a little bit crazier.
What is that?
What is that thing?
That, I think that's a bunny.
Is it?
Look.
There's his little
bunny nose and bunny,
I think those are
little bunny ears.
That's, like, the bunny madness.
Okay, I would take one of
those but I feel really sorry
for that thing because somewhere
in there is bunny.
And then of course,
like,
those are all human created,
but then there's, like,
what?
This thing.
The proboscis monkey.
This is not
artificial selection.
We did not do that.
We are not responsible.
He can honk with that thing
and make all sorts
of cool noises and guess
what the ladies think?
Whoo.
Look at his nose.
Mighty fine.
Mighty fine.
All the bigger your nose,
the more the ladies like you.
I wonder what that has to do
with parasites.
I don't know.
But, that is an example
of sexual selection.
We don't know, is there
a reproductive success
or advantage bestowed
by this phenomenal nose
or is it maybe parasite related
or is just
that the ladies like it?
But sometimes
we're unclear about that.
That's an example
of sexual selection.
We talked about the peacock
already as an example
of sexual selection.
Any sexual dimorphism,
any time
the male critter looks different
from the female critter,
you probably have an example
of sexual selection going
on because one critter
is trying to be more attractive
to the opposite sex.
Here is some other
very lovely examples
of characteristics that provide
reproductive advantage
and you look at those
characteristics and you think,
I really am not sure how that
can help you survive better.
However, part of survival,
part of the whole picture,
is making more babies.
So, if somehow a characteristic
lets you make more babies,
it kind of really
doesn't matter what else
that characteristic does.
It's kind of worth
it because then
you get to pass on your genes.
All right.
Mechanisms of evolution.
You've got a bunch of them.
In the next lecture we're going
to talk about speciation
and we're going
to look at big changes.
Like, how could we possibly
end up with different species
from these kinds
of processes that we see?
All right.
Bye.
Bye-bye.
