(bell ringing)
Now as you can see,
the flowers of these two plants
are shaped quite differently.
Does anyone have any ideas about
why the flowers of this orchid
might look different
from other types of flowers,
like the ones on this cactus?
Ooh, Ms. Reyes,
I know, I know!
(clears throat)
I think maybe Dimitri
wants to be called on.
I bet it's bright
and weird-looking
because it's poisonous.
You know, how like poison
dart frogs are crazy colors?
It's called warning coloration.
Psh, it's not poisonous.
My mom got one of those
at WalkeaMart!
It is true that many species can
signal with their coloration.
Let's hear
from some other people.
Shawna, what do you think?
(timidly):
Oh.
Maybe the orchid
looks so unusual
because it needs
to attract attention?
MS. REYES:
Very close, Shawna!
The orchid's unique appearance
attracts a very specific type
of insect pollinator,
which carries pollen between
the orchids to fertilize them.
But how did it know to make
its flowers look like that?
Good question!
The relationship
between orchids and insects
evolved over time
through natural selection,
which is the process responsible
for nearly all of the diversity
of life on Earth!
Oh!
That's what I thought.
Oh, yeah!
(bell rings)
What a glorious morning!
I'm feeling ripe
with possibility today.
Oh hey, Blossom!
That lesson went great,
so I'm feeling
pretty centered myself.
You know that I'm a big believer
in following your bliss,
but in this instance,
we may need to take
a few steps back.
Natural selection
is a tricky topic.
It's easy to misunderstand
and even easier to misrepresent.
How about this?
When the kids get back,
I'll guide you through
some of the rough patches.
Sounds way groovy to me!
(coughs)
Oh excuse me, I'm sorry.
You totally bring that out
in me.
And scientists discovered
that Galapagos finches
had evolved
differently-shaped beaks
to adapt to the particular
environments
of different islands,
allowing them
to exploit the resources
that were available there.
The finches
with short, thick beaks
are adapted
to feed on large seeds,
while those with long,
narrow beaks have evolved
to feed on cactus pulp,
allowing them to thrive
in more desert-like conditions.
I don't know about you, but
I think that went pretty well.
Hmm.
Here's an idea.
Let's take a look
at what Shawna took from that.
Then we can see if we're heading
down the right path.
SHAWNA: The finches
that can't reach food
with their short little beaks
evolve longer ones so they can.
Gah!
Okay, individual organisms
don't just sprout
the traits they need.
Natural selection whittles down
existing variation
over many generations.
New variation can arise
through mutation
and genetic recombination,
but even then,
it's only sometimes beneficial.
I know, my dear.
You're talking
to an orchid here.
Hey, that rhymed!
Poetry truly is everywhere.
Anyway,
when you said "the finches,"
Shawna thought you meant
individual finches.
Of course I know you meant
their population,
but the word is ambiguous.
Next time, make sure you specify
individual, population,
or species,
and ask your students
to do the same.
And don't worry.
This is thorny stuff.
Kinda like my friend over here.
I guess he took
a vow of silence.
I admire your commitment,
my prickly pal.
Why don't we see
how a different student
interpreted your lesson.
JUSTINE:
The warbler finch
better bulk up that beak
over time
if it wants to use
those resources.
And then it can pass that
new awesome beak to its babies!
Another misconception!
Beaks aren't like biceps.
They can't just change size
because an organism works at it.
And the traits organisms acquire
through experience or practice
are almost never passed down
to their offspring.
This is tricky.
(taking a deep breath)
Go to your happy place.
Yes.
I always thought evolution
was pretty straightforward.
Darwin, the Galapagos,
survival of the fittest...
What's to misrepresent?
A lot, unfortunately.
When you said "they adapted,"
Justine thought it was something
the finches were actively
trying to do,
like when you adapt
to a new school after a move
or when you put on a coat
in the winter.
You and I know that "adaptation"
has a special meaning
in biology,
but students who haven't learned
this stuff yet
will rely on the definitions
they already know.
Shall we dive back in?
Okay.
Natural selection is sometimes
called survival of the fittest.
The "fittest" individuals
in a population
are most likely to survive
in the environment,
and therefore most likely
to pass on their genes
to their offspring.
In this way,
populations can become
more and more "fit" over time.
MS. REYES:
This is horrifying.
ORCHID:
I know.
Dimitri doesn't yet understand
that sometimes,
it can be an advantage
to be small or spindly--
say, if it makes it easier
to hide from predators
or find enough food when
there are limited resources.
Uh, no, I meant
all the snakes and spiders!
I'm gonna have nightmares
for a month!
(shuddering)
Understanding where your
students are losing their way
is a powerful thing.
If they don't understand
the definition
of the word "fitness"
in an evolutionary context,
they might think you mean
big, healthy, and strong,
as it's used
in normal conversation.
While we're on the topic,
I'd steer clear of that
"survival of the fittest" bit;
it's quite misleading.
But I've been hearing
that phrase my whole life,
even from scientists.
How can it be wrong?
Yes, unfortunately even experts
sometimes use it as shorthand,
but they often don't realize
it can be misleading
to students.
That's because the process
of natural selection
is really all about
reproduction, not survival.
An organism that lives
a long time without reproducing
doesn't contribute its genes
to the next generation,
and therefore isn't really
that "fit" at all,
biologically speaking.
Well, speaking of "fit,"
getting my students
to understand
how some individuals can be
better adapted than others
if they're all the same species
might just put me on the edge
of having one.
That is another tricky one
for sure.
The whole process of evolution
hinges on the natural variation
that occurs between individuals
in a population
and between populations
of a species.
Just ask your students
to look carefully
at what they see out the window
in the world around them.
You can see it everywhere.
No two oaks in a park,
pigeons on a wire,
or kids in a classroom
are exactly the same.
In an evolutionary context,
these differences
give individuals
advantages or disadvantages
in different
environmental conditions,
which affects
their ability to survive,
and most critically,
to reproduce.
Let's go back in time
and try it again.
Can we do that?
Can an orchid talk?
Maybe the orchid looks
so unusual
because it needs
to attract attention?
You may be onto something,
Shawna.
Can you explain what you mean
by attracting attention?
Maybe it's good for the orchid
if bugs hang around it.
So it makes itself look stranger
so the bugs will come.
It's so clear now.
Shawna is thinking
about the orchid
the same way she was thinking
about the finches.
She thinks individual organisms
can choose to develop
whatever traits they need
to thrive in their environment.
Looks like I'm gonna have
to watch my wording
and my assumptions.
Isn't it wonderful?
By asking the students questions
throughout the lesson
and having them explain
their thinking,
you're learning
what their misconceptions are
and gaining the tools
to help correct them.
This is great!
And we've only just scratched
the surface.
There are also misconceptions
about common ancestry,
phylogenetic trees,
deep time...
Blossom, Blossom...
Okay, I guess there's still
a lot to learn,
but at least
I'll never be bored.
Are you up for another lesson?
Of course, my dear.
Hey, you wanna take
the next one?
Oh well, I tried.
To discover more
about how kids learn science
and the types of misconceptions
they might have,
visit us online
at ScienceEducation.SI.edu/
GoodThinking.
More videos from the Smithsonian
Good Thinking series
can be found over here.
Namaste!
