- I'm Dr. Thor Hanson.
And today, I'll be answering your questions from Twitter.
This is more "Biology Support".
[upbeat music]
@texastessa asks, "Hey, #biologytwitter,
if a person somehow found themselves
in the stomach of a whale, how would they die?
Would they be digested alive?
Would they drown in stomach acid?
Would they die from dehydration?"
Well, any of those things would eventually do the person in,
but what would probably get them first would be suffocation
because there's not enough oxygen
and there's far too much carbon dioxide
and other gases in the stomach of that whale
for them to survive.
@GlOOMPARKS asks,
"Why do ticks and fleas and mosquitoes exist?
Like what do they offer?
Can they die, please?
Thanks."
Well, ticks and fleas and mosquitoes may be annoying to us,
but they provide a huge amount of food
to all sorts of creatures in nature,
the bats and the birds and the lizards and the turtles.
And remember, of course,
even that the mosquitoes have a larval phase,
where they're living in the water
and they are bountiful food to fishes and other things.
So removing those annoyances from our lives
and removing them from the environment
would cause cascading effects through the food webs,
and probably eliminate a lot of other creatures
of which we are much more fond.
@slumbuddha asks, "What causes a cell to die?
#biology, #question."
Well, let me count the ways.
Cells can die from trauma.
They can die from disease.
And certain cells are programmed to die at certain times
in the lifespan of an organism,
particularly, during growth and development
and metamorphosis.
So a tadpole turning into a frog no longer needs a tail,
and those cells die off.
Or a human embryo growing fingers must kill off the cells
in between the fingers at the right time,
or the hand will come out webbed.
@anna_muller6 asks,
"Why do evergreens stay green all winter?"
The evergreen strategy allows those trees
to avoid expending all the energy
that's required in springtime to grow a new set of leaves.
They do lose their leaves,
but they do it incrementally bit by bit
so that there's always enough foliage on those trees
to photosynthesize whenever conditions are right.
@Swoosh61 asks,
"What is the most recent species to be confirmed extinct?"
Well, you include the word confirmed,
which is very important
because there are no doubt many species
going extinct right now
that we simply do not have enough data on
to say one way or another.
But a recent confirmed extinction
is one due to climate change.
The first mammal species known to be lost
to the climate crisis.
The Bramble Cay melomys, a mouse like creature
whose entire world really, all of its habitat
has now been inundated by rising sea levels
on the islands where it was found
off the coast of Australia.
@DBGreenAlliance asks,
"What is the effect of climate change on biodiversity?
How is the extinction of biodiversity
going to affect Homo sapiens as a species?"
There is an extinction crisis associated
with climate change.
We are seeing between 25 and 85% of the species
on the planet adjusting their ranges
in response to climate change.
What's the point of biodiversity in the first place?
I like to answer that in three ways
by using different sorts of cartoon characters.
The first comes to us from "Spider-Man",
where the theme is with great power
comes great responsibility.
So because our species has such power over ecosystems
and other species,
many people believe we have a responsibility
to take care of them.
The second example comes to us
from "The Sorcerer's Apprentice",
where the Mickey Mouse character in Fantasia,
the young apprentice starts reading spells
at random from the spell book and all hell breaks loose.
When we allow biodiversity to go extinct,
we don't know what we're messing with.
And the third example comes to us
from good old Scrooge McDuck,
Donald Duck's rich uncle who might ask about biodiversity,
"What's in it for me?"
Well, there's a lot in it for us as a species.
We rely upon biodiversity to pollinate crops,
to provide fisheries and forestry products.
We rely upon biodiversity to provide many of our medicinals.
And when we lose species
without ever having even studied them,
we don't know what we're missing.
@MoArtStudio asks,
"Humor me.
What extinct animal do you wish was still around today?"
It's very difficult to choose,
but I will choose the Shasta Giant Ground Sloth,
a big shambling beast that once lived in the Mojave Desert
in the Southwestern part of the United States.
I choose it because it was the sole long distance
seed disperser for another species
that I happen to really love,
the Joshua tree, those giant Yucca plants
that exist only in that desert Southwest landscape,
and that are suffering now
because they can't disperse their seeds
far enough to keep up with the changes
being incurred by global warming.
So if I could bring that species back,
I would not only get ground sloths,
but I would also ensure the future of Joshua trees.
@elisabergman asks,
"Insect Armageddon: decline of insects around the world.
How are migratory insects going to fare
in light of these environmental changes and declines?"
Well, let me answer that question with another question.
When was the last time you had to wipe bug splatter
off of your windshield?
We've all experienced that drop off in bug splatter
on our windshields.
And that gets at this question of insect Armageddon,
which is being caused by a variety of factors
from climate change to pesticides, to habitat loss,
to simply the way we manage large portions of land now
in our rural areas,
where we used to have farms that were small
and varied in crops,
we are now very efficient in the way that we farm.
We have farmed large areas with only one crop,
reducing the quality of the habitat
for a diversity of insects.
In fact, migratory insects may be at even greater risk
because they encounter numerous habitats
along their journey.
And they're particularly vulnerable to climate change,
which is altering the timing of seasonal events
so that it's possible an insect might arrive in a landscape,
expecting to feed,
but be too early or too late
to encounter that critical source of food.
@Lehlae asks,
"A quick biology question please for something I am writing.
Do plantae protista, monera and fungi kingdoms
need the anamalia kingdom at all?"
I love your question
because it really gets at the interconnectedness of nature.
Yes, we divide all living things into these five kingdoms.
The plants are the plantae, of course.
A things like amoebae and slime molds, and the protists,
the monera which describes the bacteria,
the fungi which include the familiar mushrooms and so forth.
And of course, the animals, which is all the rest of us.
But if you imagine how these things are related,
you start to see ecology in action.
Imagine the plants, for example,
without the insects to pollinate them.
Or try to imagine all of the bacteria
that live even within our own bodies
that rely upon animals for a habitat, if you will.
And fungi are turning up everywhere.
Now that we have the ability to study them
through their DNA,
we can find fungi living inside of plant leaves and tissues,
where we never imagined them before.
@BayouPhilosophy asks,
"Sorry for a dumb #biology question.
The relationship between genotype and phenotype
is causal, right?
Like the genotype [together with the environment]
causes a certain phenotype?"
The answer is yes, the genotype,
the genetic makeup of the organism causes the phenotype,
the physical expression of that genotype.
But it's not just like reading a script.
And that's because the genotype responds
to cues from the environment,
whether it's temperature or the availability of food
or other cues during the development of that organism.
So that it's possible for a genotype
to express quite different phenotypes,
depending on the conditions the organism is living in.
And one fascinating example of that
comes to us from the Gulf of California in Mexico,
where the Humboldt squid, which once grew in that region
to five or even six feet in length,
responded to climate driven warming of the water
with a different phenotype,
same genotype triggering a different physical manifestation
at a much smaller size.
The mature squid now rarely exceed a foot in length.
@comixmill asks, "Question for #BiologyTwitter:
Why do birds know to get out of the way of oncoming cars,
but mammals seemingly do not?
#deer, #headlights."
Well, the answer is birds don't know how
to get out of the way of oncoming cars.
And in fact, birds make up a considerable portion
of the estimated 1 million vertebrate animals
that are killed on roads in North America every single day,
including nocturnal birds, like barn owls,
which fly low over the roads,
and often hunt along the margins of roads
that are particularly vulnerable to being struck by cars.
@EdoVreeker asks,
"Question for biologists/biophysicists!
During a break, we found this mutated daisy outside.
To me, this seems like a beneficial form of the daisy:
larger flower, larger chance of pollination.
Why did a smaller flower and not this mutation
become the standard form of the flower?"
What you have discovered is an example
of what botanist would call fasciation,
which is a change in the growing tissues of the plant
that cause that sort of a deformity,
and it can be triggered by an infection,
it can be triggered by damage to the tissues.
But the reason that it won't be passed down,
the reason that you won't see a lot of daisies
looking like that,
becoming the dominant form for daisies is that,
it is not inherited from one generation to the next.
You get the occasional daisy with that sort of growth form,
but it's not passed down.
@FuturesGate asks, "What's the oldest tree in existence?
What's the oldest tree ever recorded?"
Well, the oldest individual trees
are certain bristlecone pine in California
and Patagonian cypresses that have been known to live
for 5,000 years.
But there are also clonal trees,
things like certain Aspens or Oaks,
where they are genetic clones of one another
living in a grove.
So while individual trunks may die off,
the whole organism can live for tens of thousands of years.
@ekarismi asks, "Okay. Random thought.
Are tomatoes really fruits?
Then ketchup would be smoothies, right?"
The answer is yes, tomatoes are fruits.
And we know this because tomatoes have seeds.
And fruits evolved for the sole purpose
of luring animal dispersers like us
into moving fruits away from the parent plant
to a new location, where those seeds might sprout and grow.
So if you are in the produce aisle
and you see something that has seeds,
whether it is a green pepper or a zucchini or a squash,
you know that it must be a fruit.
So those are all the questions that we have for today.
A wonderful mixture of topics.
Thank you for watching more "Biology Support".