Hey smart people, it’s been a while since we did one of these, and there’s a lot of
new faces out there. To celebrate our two millionth subscriber, I’m here to answer
two million of your questions. Grab a cup of coffee, we’re gonna be here for a while.
As always, you’ve been sending in a lot of comments and asking great stuff.
Like How’re y’all doing today? (Jameson Moore): First off, is “how’re” a real
word? Let’s argue about it in the comments. Secondly, great and thanks for asking.
Congrats on having 2 million subscribers (Adarsh Kumar): Yeah, that happened. Thank you! And
thank you to the other 1,999,999 of you that helped us reach this milestone, which I know
is just a random and convenient divisible-by-10 number, but is still completely mind-boggling
and awesome and I feel very lucky, so seriously… thank you times 2 million.
Which is your favourite video you’ve made and why? (Inés Laura Dawson): Favorite video?
For YouTube creators our videos are like our children, and would a parent say they have
a favorite child? No… but they would think it, because they secretly DO have a favorite.
I’ve posted over 200 videos up to this point, and my favorite one? Is probably this one
(blue ice cave). I would live in that ice cave, if it wasn’t so cold, and wet… and
full of dangerous falling rocks. That cave is just flat-out one of the most beautiful
and interesting things I’ve ever seen (besides my wife)…
How did you get into the video-making game? How did you get started with video production/did
you ever have doubts about how it would turn out? (Elaine Greywalker, Mitchell Davis):
I don’t think I’ve ever told this story on the channel before, and everyone keeps
asking, so here goes. I got a degree in biology from here, I did some research, went back
to get a Ph.D., also from here, and while I was learning all this awesome science I
realized a lot of people out there weren’t. So when I taught biology in grad school, I
started playing videos from these people, which inspired me to make my own website so
I could share awesome science with everybody, and at the top I wrote this motto, to remind
people that it’s okay to be smart, didn’t really mean for it to be the name, but people
started calling it that, so that’s how that happened. Blog got REALLY popular, so I decided
to become a better science writer, I worked there for a summer, and in the middle of it
all I got an email from these people asking if I wanted to make some science videos. I
said “sure, never done that before, why not?” and definitely don’t go back and
watch my first videos. SIGH. In the beginning, like everyone else I just turned on the camera,
tried to tell a good story, and worked to be a better writer, teacher, and creator every
week, by listening to you and being inspired by fellow creators. And 5 years later, thanks
to the wonderful, creative people that help me research and write and animate and produce
these videos, we’re having a lot of fun. Do you write your own puns? (Luis Mijango):
Of course I do! Using a ghostwriter? That would NOT be ghoul.
What’s your favorite science podcast for kids? (@TumbleCast): Excellent question, Tumble
Podcast. Have you heard of Tumble Podcast? It’s really good.
Advice on relationships? (Ashraf Ansari): If you love yourself when you’re not in
a relationship, you’ll love a lot better when you’re IN a relationship. Think about
what you can give more than what you need. And don’t worry about it lasting forever,
just focus on being happy right now, because a few billion years from now the dying sun
will swell up and vaporize Earth anyway. Will we ever see your wife be a guest on your
show? (Force_Sensitive_Tree): (shrug) If a chicken had lips, could it whistle? (Cameron
Crielaard): Not like we do, because whistling involves highly coordinated tongue movements
and breath control, and birds tongues are tiny and weird, and they actually don’t
even have diaphragms. Srsly you should look up how birds breathe, it’s weird, they’re
like living bagpipes. But birds don’t need to whistle anyway, because they have this
cool organ called a syrinx, which is kind of like if our voice box was in our chest,
and they can squeeze air through it to make all kinds of whistling, chirping, quack-a-doodle-doodling
noises that are way cooler than (whistle) like this.
Do you have any advice for others who would like to be science communicators? (Jeremy
Klein, also this tweet): There’s a lot that goes into communicating science well, but
the most important thing to remember is while we like to think of science as a big pile
of stuff to know, it’s really a way of looking at the world. People like stories more than
data, and the best way to get someone to think about something is to make them feel something.
Always remember: while facts are often simple, people are complex.
Any advice for science grad students? (Abdel Halloway): Take time for your mental health
next to all your hard work. Your value as a person is not tied to the success of your
science. And remember, you might sometimes feel like you don’t belong, but you deserve
to be there, and everyone else is just as anxious and confused as you are, they’re
just not admitting it. I wish someone would have told me this when I was in grad school.
Show us your baby! (Sa Sa4) Ok! He’s the best.
Light pollution please! (Nicole Rodriguez): Ok! (Oh, did you mean do a video about it?
Good idea!) How did you decide you wanted to work in biology?
(Luiz de Paula): I think I’ve answered this before, but there’s this saying that “all
science is just applied physics” and and physicists think they’re the coolest… but
to that I say without biology, there wouldn’t be physicists. Checkmate biology.
A few people have asked if there was a place they could send stuff to me and the show,
like real physical stuff. And the answer is yes! Details down in the description.
You guys have also been really active in the youtube comments on every video, which is
great. So now, against my better judgment, let’s read some those comments from a few
of our favorite recent videos, which you should go watch right
now. I’ll wait.
First off, to address the most common comment I got. Yes, I’m aware that the sky and the
ocean are blue, but I didn’t include them in the video, because the sky and the ocean
didn’t *evolve* to BE blue, like living things did, so I didn’t include them. Because
I’m a biologist, and living things are more interesting. Also, because this is my channel
and just because. A couple people wondered what makes pigments
different from structural colors (Victor Souza, Mjester12) : Part of the problem is that when
we say molecules have structure, or that a butterfly wing has structure, we’re really
talking about different things. One’s a way to describe how atoms are arranged, like
the structure of water. The other is the actual physical shape of some thing, like how your
house or face has structure. Ok, so white light is a mixture of all colors, all wavelengths
in visible part of spectrum. If we see something that has color, that’s because the color
or colors we see are reflected to our eyes, and the object subtracts the other wavelengths.
Difference is, that when a pigment absorbs, the energy of a photon, if it’s the right
wavelength, is literally absorbed, like a sponge, except the sponge is usually an electron.
But in a blue wing, or feather, wavelengths get trapped inside like a hall of mirrors,
and cancel each other out, like we showed in our video. So pigments work in a very different
way, one that requires special chemistry, and that’s why nature found it was easier
to make blue with shapes instead. Carotenoids (Top Fertilizer): If we eat too
many carotenoids can we turn pink? Well, no, not pink. But I was amazed to find out, you
could turn another color. If you eat enough plant foods like carrots, sweet potatoes,
squash and other colorful veggies all naturally high in carotenoid pigments, you could develop
a condition called carotenemia, where patches of your skin actually turn yellow or orange.
It’s most common in small kids or babies, when their parents are shoving mashed carrots
and stuff in their face, so obviously as an adult you’d have to eat A LOT of the stuff.
Usually not harmful, though. The cure is to just stop eating those foods. Cheeseburgers
for health!
Salem Al-Arrak comments that reading about evolutionary stable strategies, like sex ratios,
in Richard Dawkins “The Selfish Gene” really shifted their perspective. That book
is the first place I learned about this idea too. The Selfish Gene discusses a lot of what
we’ve learned about evolution since Darwin, and it’s a great book. We’ve actually
got a whole website full of books that we’ve featured in past videos. Go read and learn
you a thing. Joshua Walters had an excellent question about
purple people eaters and what they eat. They clearly are purple and eat regular people,
because if they only ate purple people, they’d starve, because not a lot of those around.
Exceptions (Actung Daniel), Ants/bees (Szenanners, JoJo Garcia, Aria Bane), Temp-determined sex
(Das Ganon). We’ll try to do a video about that in the future.
David Lazure left a great comment about how I distinguished sex vs gender in this video,
Actually, a LOT of people commented about this, but most of the others weren’t this
polite. I want to take a moment and address this. So, why would I, a scientist, differentiate
sex from gender? When people talk about these things in day-to-day life, the words are sometimes
used interchangeably, which has led to a lot of confusion. But when biologists discuss
sex, we’re referring to combinations of DNA, chromosomes, and how those genetic instructions
influence physical characteristics. Gender is a much different thing, that deals with
how different societies in different places have developed expectations or traditions
for how people act in relation to their appearance and their sex, and a whole lot of other things.
Sex and gender ARE different things, no matter what your feelings are about how they’re
used to describe people. Since my video was about genetic sex, it was important to me
to make that clear. Scientists are starting to ask a lot more questions about sex and
gender, and there’s a lot more to talk about here. Maybe we’ll come back to it in the
future.
HIV (Juan Kentoy): So HIV actually attacks a completely different type of immune cell,
T-cells, and the kind of antibody-producing cells I talked about in that video are B cells.
There’s one group of T-cells that actually helps B cells attack germs, they sort of amp
them up and help the B cells do their job, and that’s the cells that HIV kills, and
that’s why HIV weakens people’s immune systems. But HIV is super interesting and
there’s a lot to talk about there, so maybe we should do a video about that too. Lots
of video ideas! Muscle memory/autoimmune diseases/neuro-plasticity:
This video seemed to give you guys a lot of ideas for other videos. These are all super
interesting topics that there’s no way I could do them justice right now, but I love
suggestions like these so keep them coming.
Water use (Feynstein 100): Had an interesting comment about how much agriculture really
can be scaled up in order to feed more people. The truth is, no one really knows for sure,
because we don’t know what will be possible with tomorrow’s technology or in tomorrow’s
climate. But what’s certain is we’ll have to feed that population differently than we
do now. According to the World Bank, 70% (!!!) of freshwater that we use on Earth goes to agriculture,
already! So while there is some land like deserts where we’re not growing stuff already,
we don’t have extra freshwater to make that into farmland. Gonna have to be a lot more
careful with what we plant where, to make best use of water, and even consider developing
crops that use less water, which is a whole GMO question that we should probably talk
about one of these days. Burden of old age (Wan Ahmad Firas): This
is another really interesting side of the story that we didn’t talk about. Birth rates
actually slowing in most of the world, and most of Earth’s population growth is from
people just living longer and not dying as much as they used to, rather than rapid growth
in the number of people being born. So as science continues to fight aging or even gets
close to beating it, we might have a whole new population question to deal with.
Finally: Moon cheese (Ira Iguanadon): Now, the moon is NOT made of cheese, it is actually
made of rock, and covered in several inches of dust particles that haven’t been smoothed
out by wind and erosion like dust here on Earth, sharp as glass, and which would definitely
kill you if you ate it. But if it WAS made of cheese… well, the moon is roughly 22
million–million-million (22e18) cubic meters in volume, which is the volume of roughly
720 million-million-million wheels of Parmigiano-Reggiano. If all 7.6 bn people on Earth ate 27 kg of
cheese every year, as much as your average French person, then it would take approximately
133 billion years for us to eat that cheesy moon.
So, that’s around two million, yeah? Great! These were all wonderful comments and questions,
and we appreciate all your support and curiosity. There’s a ton I didn’t have time to answer,
but you can always find me out there on the internet. Thanks and remember…
Stay curious.