In this lecture, I am going to explain the use of natural science in building a city’s ecology.
However, rather than starting the lecture
with physics,
or biology,
I will start it
with history.
In ancient times,
humans were aware of the existence of frogs;
they listened to frogs sing
in good days;
ate frogs for food
in bad days;
included frogs in calligraphy works
for recreation;
and utilized frog skin as medicine
to cure sickness.
Frogs are, in fact,
an important, valuable animal
whose values are yet fully explored.
In the early days, Chinese people found that
frogs ate insects in significant numbers,
which made frogs an excellent means of pest control in farming.
The Chinese people thus kept grass along ridges
and irrigation waterways beside fields
for frogs to hide
and move freely between waterways and fields, respectively.
Therefore, fields generally
contained an opening
as a water inlet,
and another opening
as a water outlet.
Frogs were able to move freely between waterways and fields
as long as there were openings installed for water inflow and outflow.
In 17th century BC,
Moses destroyed Egypt
using God’s frogs.
That's why in Egyptian
the frog is the numeral for the largest counting unit
it is equivalent to approximately 100,000.
The Greeks found
that frogs stayed on the surface of water
in good weather
and sank to the bottom of water
in poor weather (i.e., when it rained).
Such a phenomenon made frogs a good barometer.
The reason why frogs are able to detect atmospheric pressure
is because their lungs are connected to their nostrils,
making them highly perceptive to atmospheric changes.
In Rome, frogs are called
Rana.
I assume that this is because that it is the sound that frogs make in Rome.
"Rana Rana"
By contrast,
toads are called
bufo in Rome.
"Bufo Bufo"
In taxonomy,
Rana and bufo
are the scientific names of frogs and toads, respectively;
the two names remain commonly used.
By performing an experiment using frogs,
Leonardo da Vinci
proved the effect of brain on limb functions.
Frogs were selected because they share similar anatomy as humans.
Thomas Browne,
the father of biochemistry,
found that frogs need moisture
to breathe.
He also learned that frogs
are animals that do not need to breathe via its nostrils;
they breathe with their skin.
This is the reason why frogs often stay near water.
William Harvey made a very famous discovery:
using frogs, he found that the beating of heart
enables blood to flow inside the body,
leading to the birth of modern anatomy.
Anton van Leeuwenhoek
dissected tadpoles
and found that frog growth
contains various stages.
Jan Swammerdam
discovered that the muscle movements, sense of taste,
and vision of frogs
are highly similar with those of humans.
As the understanding of frogs helps humans understand themselves,
dissection experiments using frogs subsequently emerged.
Mark Catesby,
an 18th century explorer,
discovered a type of bullfrog that he had never seen before in North America.
He made the frog into a biological specimen
then shipped it to Carl Linnaeus in Sweden,
who then gave the said frog a scientific name,
facilitating the birth of modern-day frog taxonomy.
Luigi Calvani found that frogs' jumping
is propeled by electric currents transmitted through nerves; this finding
gave birth to modern electrodynamics.
People’s attention to frogs continued well into the 19th century
and their knowledge about frog behavior, reproduction, and physiological characteristics further expanded.
George Albert Boulenger,
the most famous frog taxonomist
among all frog taxonomists,
named 2,500 types of frogs during his lifetime.
This accounts for 60% of the 4,000 frog types found around the world.
A very interesting fact
about the naming of frogs.
I started studying frogs 15 years ago.
Why?
Because I love photography.
As a photographer, there was a major problem that I was unable to overcome:
I was unable to capture
the image of a frog sticking out its tongue.
I simply could not get it.
I would be prepared to take a picture of a frog sticking out its tongue
but I simply could not capture the image.
This was because that a frog would stick out its tongue
and “pah!” (sound of the tongue hitting the prey).
and that was it.
Frog tongue measures from 80 cm to 1.5 m;
when a frog sees an insect,
it would shoot out its tongue, “pah!”
the tongue sticks the prey,
and flips back, “pah!”
All of this happens in 0.1 sec.
Despite my camera being equipped with a shutter,
I was never able to capture such an image.
Part of it was because that it shot out its tongue in different directions.
It could stick out its tongue like this,
or move to the back,
“pah!” and then flip back.
Yes, it can turn its tongue 360°.
So…
It goes “pah!” “Pah!” “Pah!”
in 0.1 sec.
I often think to myself,
“if I had the tongue of a frog,
would I still have to pay for food ever?”
When a frog sees a prey,
it does not
move towards it.
Instead, it waits for the prey to come.
So, let’s pretend that
the frog is standing here,
it sees a prey moving in front of it,
it would remain where it is.
If the prey is here,
the frog would turn like this.
Okay?
So if the prey is here,
the frog would turn like this.
Okay.
A frog always stays in the same spot.
It would not move towards its prey.
No,
it wouldn’t.
Okay?
Frogs know how their tongue works,
so they rarely go after their prey;
they just sit quietly,
waiting for the prey to come,
catching it with their tongue.
how magnificent!
Their tongue is a rare weapon seen in the animal kingdom,
one in which it can shoot out
from their mouth
catch the prey,
flip back,
and carry the prey into their mouth.
It takes only 1 sec
for the aforementioned movements to complete.
If humans ate like frogs,
buffet owners would lose their mind.
They would see food disappear before their eyes
and customers chewing constantly,
but they would not be able to see how the food got into their mouth.
The structure of the frog's tongue is unique.
It operates on the principle of water pressure.
Between the muscle fibers of the tongue
is water, which occupies 1/3 of the pores.
Water pressure allows
the tongue to flick out.
The water pressure phenomenon is observed
in many organisms.
Flowers, for example,
bloom in the morning or at night,
and flowers bloom
because of water pressure,
water pressure.
Okay?
The pressure from water
induces the leaves to close.
Therefore, the reason why many leaves close is
because of water pressure.
Similarly, the said water pressure causes the tongue to roll back.
In general, frogs shoot out their tongue at a rate of 0.1–0.4 m per sec;
if you include acceleration,
it reaches 3.5 m per sec.
Frogs jump beautifully.
I don’t know whether you have seen frogs jump…
They have very long hindlimbs
and very short forelimbs,
Okay?
Very few people can jump like me,
Okay?
Once again, long hindlimbs
Okay?
and short forelimbs,
okay?
Basically, for a frog to jump upward,
it must press its hindlimbs downward
and all the way down.
In addition, it must keep its center of mass
in the front.
Have you ever seen a frog like this?
No,
of course not.
Its center of mass leans forward,
so it presses its hindlimbs downward,
all the way down,
until it reaches a certain point,
then it jumps.
In general, the angle at which
it jumps upward is greater than 45°;
however, such angles differ between frogs from different countries.
How does a frog place its forelimbs
while in the air?
Its forelimbs would slowly open.
Conversely,
its hindlimbs would
slowly contract.
How does a frog
land?
It would gently touch the ground,
then
the recoil force
would allow it to stay down.
There is a very unique hallway in the National Taiwan University
that was designed for frogs.
The said corridor is located by our ecological pool.
You must remember the bridge by the ecological pool, right?
The National Taiwan University names that bridge
the “Naihe Bridge.”
People think that the bridge was given such a name because of the expression “having no alternative” (pronounced wuke naihe in Mandarin),
however, that wasn’t the case;
the Naihe Bridge was actually designed for frogs.
Because we have a large number of frogs in the ecological zone,
we designed a bridge to provide
a platform for frogs to jump up and land
without the risk of
being run over by bicycles,
dying from the process.
So we built another bridge
on top of the bridge,
with the bottom bridge being used by frogs,
enabling them to enter of the premise of our School of Forestry and Resource Conservation.
The frogs would be able to survive
as long as they entered the ditch within the scope of the School of Forestry and Resource Conservation.
When we introduced frogs to the ecological area,
we had many frogs in the first
and second year.
However, all the frogs eventually disappeared.
Do you know why?
It was because of the presence of a “troublemaker,”
the channeled applesnails.
They took over the ecological pool.
We were later forced to put black carps in the ecological pool;
we put a total of 500 black carps in the ecological pool
to eat the channeled applesnails.
Thus, you will not see any red eggs laid by channeled applesnails
in the ecological pool
because they have
all been eaten by black carps.
However, the black carps also ate our frog eggs,
resulting in the failure of our solution.
Although we failed to successfully breed frogs,
the experience allowed us to
succeed in other areas, where we
brought more frogs back to the city of Taipei.
We want to let the children know
that frogs' croaks are pleasant
Many do not know how to appreciate it.
The fact is that
a frog can make many different sounds;
such sounds include those made to scare off potential threats,
to serve as a reminder to other frogs,
for courtship,
and to be used as a tentative call.
okay?
Most people cannot discern the differences between these sounds;
only a few can.
Sometimes a frog croaks to find out whether there are other animals in the vicinity.
If so, it may stop croaking.
Why?
Because it is studying whether it is being watched.
However, if it finds no others around,
it would start croaking again,
okay?
A frog can make at least
seven to eight different sounds.
Taipei was originally a basin, and
basins start off as swamps.
One may thus ask the question,
“if Taipei started off as a land of swamps and wetlands,
why is it that we don’t see any frogs?”
Well, there were frogs in Taipei in the past;
however; people would use pesticides
to kill the frogs as soon as they hear frogs croaking,
okay?
They complained that the frogs are too noisy.
So, frogs had originally inhabited Taipei.
They were the natives,
whereas humans were the aliens.
“Why are there no frogs in Taipei?”people would ask.
This prompted us to start thinking about
ways to reintroduce frogs back to the city.
Having learnt from our mistakes from the ecological pool experience,
we knew that if we were to reintroduce frogs
back to the city,
the water depth would have to be no more than 2 cm.
As long as we kept the water depth to 2 cm or under
and ensure adequate water quality,
yes, adequate water quality would suffice,
frogs would be able to lay eggs there
without the danger of being eaten by fish.
Therefore, we began building an ecological pool with a depth of 2 cm.
Well, it was inevitable that some areas of the ecological pool
the depth exceeded 2 cm;
some areas had a depth of 3 cm,
4 cm,
or 5 cm.
We surrounded the areas
with a lot of plants as shelter.
We used a lot of ferns
and placed them
by the ditch as shelter.
This provided a place for frogs to hide
as well as to enter/leave the ecological pool safely.
Concerning the slope,
we used the common standard
of less than 30°;
this angle allows frogs
to travel between the two areas
with ease. One may ask whether
snakes would be a threat to these frogs,
and the answer would be “yes.”
In essence, the protection of an animal
entails the protection of also its natural predator,
Is it right?
Okay?
Therefore, we also allow
the presence of snakes in this area.
We asked ourselves whether it was possible
to use marginal lands in the highly
urbanized city of Taiwan
to build a place for frogs to inhabit.
Our efforts were proven successful.
Our efforts consisted of
observation,
understanding,
and persuading others to see
the possibility of repopulating frogs in their area.
Some of these people would later complain about the noise that frogs made,
to which we would reply,
“these are not noises,
but the sounds of nature,”
Okay?
This is the music of nature,
okay?
One must understand
that the reason why he/she would consider such sounds as noises
is because he/she does not know what the sounds mean,
okay?
For example, “croak” means “come,”
okay? It's the frog's welcoming call. 374 00:10:24,640 --> 00:10:26,140 okay? “Come!”
Okay?
What I was talking about was the calls between a male and female frog for each other,
okay?
It is a tentative call,
okay?
It is used to see whether predators are nearby.
So we began with
understanding the frogs,
after that we engaged in ecological projects.