Hey! Welcome back to Big History. I'm Rachel Hansen,
and it's finally flannel Friday. Ah, I love a good flannel. I'm also really excited,
because we got a heck of a
lesson today, people. Let's get it started.
Here's our driving question: How did Darwin arrive at his theory of natural selection?
So who's this guy Darwin? Maybe
you've heard of him, Charles Darwin? Well,
when he was 22 years old,
he set sail on a voyage - an expedition -
around South America, and he ended up in
the Galapagos Islands. And the
observations that he made there of the
plants and animals led him to create the
theory of natural selection. So, what is
it that you think he observed there, that
led to the development of this theory?
Now our word of the day is natural
selection. So, what is natural selection?
Natural selection is a process that
results from the evolution of an
organism in a way that makes it best
adapted to survive in its environment. So,
what Darwin was observing on the
Galapagos Islands, particularly among the
birds (among the finches), was that their
beaks were different shapes and different
sizes, because they were adapted to the
food that they were eating. So, you know
like, if they were eating small seeds, or
large seeds, or fruit, or insects, they had
different sizes and different shapes of
beaks. And these were traits that had
been passed down generation to
generation, these small changes that were
made along the way. And natural selection is this idea that those
that were best adapted to eat their food
in their environment survived, and the
ones who weren't - they died. So, I thought
maybe we could test this thing out! With uh, some
things you can find around the house for
bird beaks! Why not? Let's give it a whirl.
So here we go: natural selection, distance learning style. Okay, so here it is: our
lab on natural selection and adaptation.
We're going to test out four different
bird beaks in this scenario. The tongs
here, like a pelican, my makeshift
chopsticks, like an avocet, a spoon, like
a spoonbill bird - these little guys,
tweezers! - like a Finch. And, in here,
I've got - oh, there goes our macaroni, our
big bugs. I've got all of these pieces of
bird food! So there's some rice in here
for, like, little itty bitty insects,
there's some raisins and almonds, for
like, beetles or other bugs, there's some
slivered almonds like, maybe clams? And
then these big noodles, like big hard
noodles, like maybe a big old piece of
fruit or something. So uh, yeah! We'll do
rounds of 30 seconds, and we'll see how
much food I can collect! Six pieces of
food means you reproduce and survive,
three pieces means you die! What should we start with? I mean, I love a good
challenge - let's start with the
chopsticks, the avocet. Alright,
thirty seconds begins. Oh - and also,
everything's got to go into my belly -
it's my little bird stomach right here,
can't move it, can't touch it, it's just
all gotta go in. Oh, my stomachs growling, I'm hungry! Ready? Go! Don't die, don't die
little guy! Four. Three raisins (three
beetles), and a big bug. Uh, let's go for
the spoon - something a little easier. I'm
just gonna scoop stuff up like crazy, I
bet this is the big winner, that's my
hypothesis. Oh, harder than I thought!
Nothing that can escape the wrath of the
spoon! Boom! Oh, look at all of this stuff!
The spoonbill bird for sure just made
lots of babies - reproduced like crazy! Such
a great adaptation! Let's go to... the
tweezers! Alright, my strategy? I'm gonna
pick up all that rice - just like ttttt - so
much rice. Okay, 30 seconds - begin. Well,
just shot a piece of rice into the window!
Oh gosh, small but mighty - 14 pieces of
rice in here! Not too shabby for the
little Finch - who knew?! Gosh, I kind of
thought maybe the tweezers were gonna be out. My only regret is, I didn't stab any raisins...
Could have been stabbing raisins the
whole time like that! Hmm, those raisins are
good! I think for this last round I'm
gonna eat my food. Alright, we're on to
the pelican! Look at that monster beak.
But in this round I'm actually gonna eat
this stuff, cuz, I'm hungry. Begin! Almond, almond - get in my belly. Harder than
it looks! Get a little raisin, guy.
I can get one of these though. Ow, hard! Almond! My teeth are breaking!
Time is up - so I got three really hard
pieces of spaghetti.
Well, let's see what we've learned here today.
Alright, so, here we go. This was my last round with
the pelican, barely scraped by with three
pieces of food, so I think I barely
survived - but I didn't consume enough
food to reproduce, so the pelicans aren't -
that doesn't bode well for the pelicans. Our spoonbill bird here:
crushed it, totally crushed it, like -
absolutely is thriving. Our little guy
the finch: total underdog, plenty of rice.
14 grains - finches, this beak is well
adapted for those little insects... but if
our environment ever runs out of those
little insects you are a goner. Chopsticks here: three beetles and a
big one, a big bug. Our avocet is probably not gonna make it, but... there's still some really good food in there.
So, yeah! Natural selection - Darwin
had it going on! What else can I eat out of here? Not you....
All right y'all. I guess that's it. Okay,
now today you've got your own activity -
you're gonna head over to Khan Academy,
and you're gonna do the activity "The
voyage of the Beagle". The Beagle, (not the dog!) was the name of the ship that Darwin
was on. And in this activity, you're gonna
look at and analyze maps and images from
Darwin's journey, and as you're looking
at them and analyzing, think about: what
did Darwin see that led him to this
theory of natural selection? Alright -
get on over there, I'm gonna go scrounge up some more food.
Welcome back. Alright, now today, in your historian's journal,
I want you to think about: how is the
coronavirus adapting? I mean, it's a
pretty resilient little bug - we know it's mutated, it's adapted over
time, so how's it mutating? We know that
it can pass on to big cats, to tigers -
it happened in the Bronx Zoo! So, what
changes is the virus making over time to
adapt, and what changes do you think
it'll make in the future? So, go research -
how is this thing mutating to adjust to
new environments and to new hosts?
Can't wait to hear what you find out.
Gosh, it's been a great week. You guys,
it's so much fun being here with you.
We're almost to the halfway point, so
I'll see you after this really great
weekend, for some more Big History!
Be good, y'all take care. I'll see you next
week.
