Download Natural Selection Script (long) - University of Alaska Anchorage

Script Natural Selection version 15
as recorded.
Black text: Narrator
Blue text: Charles Darwin
Red text: Captain Fitzroy (recommendation: do not translate this)
Purple text: Queen Victoria (recommendation: do not translate this)
Green text: Harrison Schmitt Apollo 17 astronaut (recommendation: do not
translate this)
------------------Coelacanth-----------00:32
Deep down along the East African coast, hidden in underwater caves, we find
the Coelacanths, fish from another time.
00:42
These 400 million year old living fossils were once thought to have become
extinct along with the dinosaurs.
00:50
Possibly the sole remaining representative of a family of fleshy finned fish.
00:57
Perhaps the ancestors of amphibians that started to roam on land.
------------------Opening Dover --------02:32
When we look at the World around us, we can tell it has not always been the
same.
02:37
The top of a cliff was once the bottom of the sea.
02:41
Fossilized shells of long gone ocean creatures can be found right here.
02:47
Since the Earth was formed many exciting changes have occurred.
02:52
The key is time.
02:54
The long geological history of the Earth dwarfs our own human history.
…..
03:25
In the 19th century in Victorian times people had a different perception of the
Natural World around them.
03:33
Most people stuck to the conventional belief that the Earth is only a few
thousand years old.
03:39
And is populated by species that are the same today as they were when
originally made, during the single week in which the Creator formed the entire
Universe.
03:51
In 1842 Queen Victoria had seen the Orang-Utan in London zoo.
03:57
She was less than amused:
04:00
‘The OrangUtan is too wonderful … he is frightfully and painfully and
disagreeably human’
04:10
Around the same time fossils of large extinct dinosaurs were gradually being
unearthed and described.
04:18
Even then scientists recognized that extinction had been a common
occurrence in the history of life.
04:24
But how could new species appear to replace those lost through extinction ?
04:29
It was time for someone to come forth with a naturalist explanation of : “this
mystery of mysteries”….
05:12
Welcome to Down House, the home of Charles Robert Darwin during the last
40 years of his life.
05:22
It was here where Darwin wrote his famous book: On the Origin of Species by
means of Natural Selection.
05:31
The book that challenged a Worldview that had been taught for centuries.
----- Darwin speaking to the audience in the study of Down House ----------05:40
“I am delighted by your visit and humbled that you are here to learn about the
ideas I had during my blessed youth”.
05:49
“I didn’t enjoy or do well at school but no pursuit gave me so much pleasure
as collecting beetles”.
05:56
“My father worried that I would end up being a disgrace to myself and the
family”.
06:02
“But when I was only 22 years old in 1831 I was invited to sail as a naturalist
on board the HMS Beagle, whose mission was to circumnavigate the World”.
06:15
“At first my father opposed it, but in the end he relented, and I accepted the
post”.
06:23
“The voyage of the Beagle has been by far the most important event in my
life, and has determined my whole career”.
------ HMS Beagle -------------------------
-------- Patagonia-------------------------10:16
The primary mission of the Beagle was to chart poorly known stretches of the
South American Coastline.
10:23
Darwin was not a hired biologist but had to pay for his own trip as a
gentleman-companion to captain Fitzroy.
10:32
While the ship’s crew surveyed the coast, Darwin spent most of his time on
shore, observing and collecting thousands of specimens from the wide
diversity of exotic plants and animals.
10:45
Darwin’s life now had purpose. He would follow his heart and become a
scientist.
10:53
He was filled with excitement as from an early age he had a passion for
nature.
----- Albatross --------------------------------------------------------------------------------------- Darwin’s voice ----------------------------------------------------------------------------11:28
“I do not believe that anyone could have shown more zeal for the most holy
cause than I did for shooting birds”.
----Night shots Beagle ------------------------------------------------------------------------11:40
Captain Fitzroy had given Darwin a new book called principles of Geology by
Lyell a geologist.
11:48
Lyell wrote that the Earth had been formed not in a few days but over a long
period of time by natural processes such as volcanoes and earthquakes
11:59
Darwin was fascinated !
------------------Earth Quake ------------------12:05
Then on February 20th 1835 Charles Darwin experienced an earthquake
himself in Valparaiso, Chili.
12:20
The nearby town of Concepcion was ruined by the Earthquake.
12:26
It was one of the most interesting spectacles he had seen since leaving
England.
------------------Shells pushed above water ---12:35
At the same time captain Fitzroy found beds of mussel shells still sticking to
the rocks, way above high water mark as a result of the Earthquake.
------------------ Andes --------------------------12:49
Darwin found fossilized shells high on the tops of the Andes. Could mountains
have been formed by many many earthquakes over a long period of time ?
---------------- Milky Way ----------------------13:04
Darwin was sure Lyell was right. Natural Forces like volcanoes and earth
quakes HAD changed the Earth in the past and the Earth is STILL changing
today!
----------------- Flight Galapagos--------------13:27
In 1835 the Beagle set sail for the Galapagos archipelago.
13:34
Islands of relatively recent volcanic origin that lie on the equator quite a way
west of the South American coast.
13:42
Darwin wrote to his sister: “I am very anxious to see the Galapagos Islands, I
think both the Geology & Zoology cannot fail to be very interesting.”
13:54
This would turn out to be a huge understatement.
-------- Rowing boat ------------------------14:22
Darwin found the strangest creatures that seemed highly adapted to their
habitat and showed similarities with creatures of the South American
mainland
-------- Marine Iguanas --------------------14:32
Marine Iguana’s that feed on algae from rocks along the coastline.
14:39
Darwin wrote: “The black lava rocks on the beach are frequented by large
most disgusting clumsy lizards. They are as black as the porous rocks over
which they crawl & seek their prey from the sea.”
15:09
He observed animal behaviors that he had never seen before.
------- Blue footed booby ----------------------
15:15
The blue footed booby waves and shakes his blue webbed feet to give the
females a thrill.
15:22
These are his best foot lifting efforts.
-------------- Galapagos Tortoises -----------------15:32
Higher up on the slopes of the volcanos, Giant Tortoises graze.
15:39
Darwin was told by the locals that one could tell which island a tortoise came
from by looking at it’s shell.
15:47
It took a while before he grasped the significance of this news.
15:53
Most of the animal species on the Galapagos live nowhere else in the World.
--------- Flightless cormorant --------------------------------------------------------------16:00
Like this flightless cormorant, ……..
16:07
Darwin asked himself: Why did God create birds with non functional wings ?
(captain Fitzroy reading red text)
16:14
, and fowl that may fly above the earth in the open firmament of heaven.
----- Coral Reef -------------------------------------------------------------------------------16:20
Darwin, who almost became a clergyman himself, never missed a single one
of the Sunday services conducted on board the Beagle by Captain Fitzroy.
(captain Fitzory reading red text:)
16:28
And God created great whales, and every living creature that moveth, which
the waters brought forth abundantly, after their kind, and every winged fowl after
his kind: and God saw that it was good. And God blessed them, saying, Be
fruitful, and multiply, and fill the waters in the seas ……...
………
19:44
By the end of the Beagle’s 5-year voyage the young Charles Darwin had
become convinced that life on Earth had evolved by natural causes.
---- Sandwalk Charles Darwin speaking to the audience -------------19:57
“We can allow planets and the sun to be governed by natural laws, …….but
the smallest insect, ……………we wish to be created at once by special act”.
20:13
“During the voyage of the Beagle I had been deeply impressed by the
Galapagos archipelago and the manner in which species differ slightly on
each island”.
20:29
“The natural barriers of Islands seemed to be a vital ingredient in the origins of
new species”.
------ garden -----------------------------------------------------------------------------------20:41
In order to make a solid case for evolution, he needed to explain how
evolution happens.
20:48
He wondered: If the World has changed so much during its long geological
history, then perhaps all living creatures have somehow gradually adapted to
fit in with the slowly changing environment, otherwise they would have
become extinct.
21:05
The survival of life on Earth can only be explained by the idea that
unsuccessful species are replaced.
21:14
There must be a natural law that explains how new species replace the old
ones.
21:45
Less then two years after arriving home, Darwin found his mystery of
mysteries, and named it : Natural selection.
21:57
Let’s have a look at how it works:
------- cardboard figures explanation 1 --------------------------22:03
On this island live two individuals of the same species.
22:07
A smaller one and a larger one. Both can happily survive by eating grass and
procreating.
22:15
Then by chance….. a geological barrier divides the group in two.
22:21
The environment on the left becomes drier. Food becomes increasingly
scarce. The larger individual on the left dies because it needs more food
than the smaller one.
22:33
Very soon the population on the left of the island only has small individuals
while on the right there are only large ones.
------ iguanas adrift -------------------------------------------------------23:03
Sometimes species can bridge an existing geological barrier themselves.
23:09
Iguanas from the South American mainland might be cast adrift perhaps due
to a tsunami.
23:21
Clinging to a tree for weeks they could cross the pacific and only if they are
very very lucky, land on an island.
23:32
The new environment selects very different traits, resulting -after many
generations- in a very different Iguana.
23:41
Let’s look at another example:
----------- cardboard figures explanation 2 ------------------23:44
One species has developed spines to protect itself against a predator.
23:49
A geological barrier means that the predator can only reach the individuals on
the left. Variation in the offspring cause some individuals to have larger
spines, some smaller. The ones with the smaller spines get eaten first.
24:07
Without a predator on the right side there is no pressure to keep the spines.
24:12
And in nature: if you don’t use it you lose it.
24:18
Little changes like these can accumulate into major changes, creating new
species that can no longer reproduce with the original ones.
------ Blind cave fish -------------------------------------------------------24:34
These blind cave fish have no eyes. They originate from deep caves in
Mexico, where the lack of light and predators made eyes unnecessary.
Instead they find their way around by means of a highly sensitive organ which
senses vibrations in the water.
-------- Peacock ---------------------------------------------------------------------24:59
Natural Selection WORKS - because more individuals are produced than the
environment can support.
25:06
This leads to a struggle for existence among the individuals of a population.
25:11
These individuals vary in their traits.
25:17
Nature selects those with the traits that best fit the current environment and
passes them on to future generations.
25:26
THAT is survival of the fittest.
25:31
But for a long time Darwin could not explain the beautiful plumes of the
peacock by Natural Selection
25:38
The large plumes seemed to make the peacock more vulnerable to predators
and less efficient in flight.
25:44
Darwin used to say: “the sight of a peacock makes me sick”
25:50
The answer to this problem is: Sexual Selection.
------- Flamingo scene ---------------------------------------------------
------------- Sexual Selection explained cardboard figures example 3 ---------26:19
With sexual reproduction a favourable green colour is distributed very quickly
through the entire population.
26:27
This new green population is still a mix of many individuals.
26:32
The key thing sex does is to create variety.
26:36
This makes the species more responsive to future changes in the World
around them.
…..
26:43
When females choose a male they tend to choose the best or strongest
looking male as this represents his fitness. This lucky male will get more
offspring.
26:54
That is why the clumsy plumes of the peacock are still favored by evolution.
26:59
Female choice means that sexual selection can shape the bodies and
behavior of their males.
------ Moose meets Moose -----------------------------------27:18
Posing alone is often not enough.
27:21
The large antlers of the Moose are there to impress females AND to combat
other males.
27:28
There is a lot at stake. The strongest male gets the right to mate.
27:33
In the end it is really the females that are in charge of evolution.
--- Egg cell -----------------------------------------------------27:37
From the very start they invest the most in the offspring, starting with a limited
edition egg cell.
27:44
Only a few hundred are available in the female’s lifetime as opposed to
billions of reproductive cells for males.
…..
28:13
It pays off for females to demand the best of the best !
------------- Tree of Life ---------------------------28:30
But where do we fit in, in the story of natural selection ?
28:34
Are we the crown of evolution? No, we have a more modest position.
28:40
We are just one of the many species on the tree of life.
28:46
This majestic family tree unites all species that ever lived on this planet.
…
28:53
It never stops growing producing only intermediates and never an end
product.
…..
29:34
There is an unbroken thread that stretches from species that are alive today
to the last common ancestor of all life on Earth.
29:43
The origins of life, cannot be explained by evolution, but almost everything
else that ever happened since..... CAN.
-------- macro evolution scene Darwin speaking at end -------------------------------------33:08
We must, however, acknowledge, as it seems to me, that man with all his
noble qualities ….. still bears in his bodily frame the indelible stamp of his
lowly origin.
--------- Darwin speaking to audience in hallway----------------------------------------33:26
“For many years I kept my secret species theory right here in this cupboard
and did not dare to publish”.
33:34
“Until I received a letter from a naturalist colleague named Wallace.
He independently proposed the theory of Natural Selection himself”.
33:46
“We published our essays together and then I hasted to finish my book “On
the origin of species by means of natural selection”.
33:55
“It was like confessing a murder !”.
------- Robin bird ------------------------------------------------------------------------34:09
Darwin was sure that variations were passed on from generation to
generation but he had no idea how.
34:18
Now we know how.
------ the Cell --------------------------------------------------------------------------
34:40
All creatures are made up of tiny building blocks called: Cells.
34:46
Inside we are uncovering a World Darwin never could have imagined.
…
35:08
All the information of heritable traits is stored in DNA.
35:16
It defines everything... from the color of hair, to the shape of hands, and the
size of feet.
…
35:35
All variations in a species start here.....
35:41
by occasional mistakes in copying, and by mutation.
35:45
THAT is the basis of evolution.
35:53
And the variation is passed on from cell to cell and generation to generation.
----------- After Darwin Virtual Evolution -----36:04
Today we can test evolution with a computer program which creates virtual
block creatures.
36:10
A population of creatures is selected for their ability to move......
36:17
Those that are most successful survive and have offspring with variation.
36:25
And what happens? just by creating random variations the computer has
simulated nature,
36:33
After many generations of selection the creatures start to look (as Queen
Victoria would say) 'disagreeably human'.
------ Hammer Head Sharks -----------
37:13
What Charles Darwin glimpsed nearly two centuries ago is now the
foundation of biology.
37:21
Evolution by Natural Selection has changed our perception of our place in
nature for ever.
37:28
It just needed someone with a love for nature and an open mind to witness
the role islands play in shaping life.
------- end island scene -------------------------------------------------------------------38:28
Darwin’s 'mystery of mysteries' is an eloquent and grand explanation that
reveals to us that we are united with every other species on this marvelous
planet.
…….
38:49
A planet that is an island of its own.
38:52
Shaping every living thing on it.
38:56
Because this planet is not made for us, we are made for this planet!
……
(Harrison Schmitt Apollo 17 original recording)
39:11
This valley has seen mankind complete its first evolutionary steps into the
Universe, leaving the planet Earth and going forward into the Universe.
(Darwin speaking)
39:35
And if we ever find live beyond Earth among the billions of planets and moons
orbiting the stars in our Universe, then it almost certainly will have to have
had evolved by means of Natural Selection.