Big Era One
Humans in the Universe
13 Billion – 200,000 Years Ago
1
Welcome, fellow time travelers!
Me llamo “Mundo!” Nice to make
your acquaintance. I don’t know
how you found me, but I think
you’ll be glad you did. Since
you’re here and so am I, let’s
take a little trip, huh?
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I’m glad you’re here!
People have been kind of
ignoring me lately, so I’ve
been thinking a lot and
wanted to share this story
I’ve been writing. It’s about
me, of course (it’s my story,
right?), but it’s about you,
too...
Let me start with a couple
of questions I’ve been
thinking about...
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How did
the universe
come to be?
Where did
our Earth
come from?
How & when
did we humans
appear on Earth?
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Deep questions, huh?
Yeah, but I’m not the only
one asking them...
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All peoples have explanations of our origins.
The Maidu people, native to California, say
that Earth Starter made the world from
some green slime Turtle brought up from
deep underwater. He made humans from
red earth mixed with water.
… And the Chinese used to
say that Phan Ku – no
thing, not yet born – burst
from a hen’s egg and
became the Great Creator.
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Scientists offer a different explanation, based on
evidence gathered from sources on earth and in space.
Here’s what they might say:
Long ago, there was no time...
There was no space...
But 13 billion years ago...
things changed.
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BANG!
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Where there had been
nothing, now there was
everything. The whole
universe – tiny, and
fantastically hot.
For an instant, it
expanded faster than the
speed of light. Then it
slowed down but kept
expanding, as it still is.
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Big
Eras
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Big
Bang
As the universe cooled down,
clouds of hydrogen and
helium gas began to gather
together, their centers
getting hotter and hotter.
13 bil yrs ago
Big Era 1
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And when they
were hot enough, the
hydrogen atoms began
to fuse together with
the power of millions of
hydrogen bombs.
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STARS
WERE BORN!
12
They clustered together
in vast galaxies, each
containing billions of
these new stars.
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Big
Bang
I can’t
see us
yet...
Stars &
Galaxies
13 bil yrs ago
Big Era 1
12 bil yrs ago
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Four and a half billion years
ago – when the universe
was already two-thirds as
old as it is today – a star
was born near the edge of a
galaxy we call the Milky
Way:
Our Sun &
Planets
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Eras
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Stars &
Galaxies
Big
Bang
OUR SUN!
12 bil yrs
ago
13 bil yrs
ago
Big Era 1
4.6 bil yrs ago
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Around the sun, wisps of matter were drawn together by the
forces of gravity to create the planets of our solar system…
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…Including the third
rock from the sun:
OUR EARTH!
What a
cute baby,
huh?
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The early earth was
incredibly HOT.
Heavier metals melted
and sank to the center,
lighter metals rose to
the surface, and gases
bubbled up to make the
earth’s first
atmosphere.
Anybody got
something for
a stomach
ache?
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By four billion years
ago, the earth had
cooled enough for
water to condense into
oceans. And so the
earth turned blue.
The surface hardened
into thin “plates”
floating on the molten
materials underneath.
Those “plates” float on
the surface to this day,
constantly changing the
landscapes and weather
patterns on the earth’s
surface.
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Where the plates collided, great
mountains were formed...
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...and where they tore
apart, melted rock
poured out from under
the surface.
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Deep within the newly
formed oceans,
complex chemicals
were created using
volcanic heat for
energy.
First
Life
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Our Sun
& Planets
Stars &
Galaxies
Big
Bang
Some of these
chemicals became so
highly organized that
they formed cells – the
first LIFE ON EARTH!
4.6 bil yrs ago
12 bil yrs ago
13 bil yrs ago
Big Era 1
3.8 bil
yrs ago
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Living organisms changed
the atmosphere, adding
oxygen. Cells developed
that could “breathe”
oxygen...
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First Life
Our Sun
& Planets
Stars &
Galaxies
Big
Bang
...and, about 600 million
years ago, the first multicellular organisms arose
in the earth’s oceans.
Multi-Celled
Organisms
3.8 bil yrs ago
4.6 bil yrs ago
12 bil yrs ago
13 bil yrs ago
Big Era 1
600m
yrs ago
Big
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The first animals appeared
not too long after!
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First Life
on Land
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First Life
Multi-Celled
Organisms
After a while, some
animals moved out of the
oceans and onto the land.
400m
yrs ago
250k yrs ago
Today
600m yrs ago
3.8 bil yrs ago
Scale of Life on Earth
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First
Dinosaurs
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First Life
on Land
Dinosaurs were the most
successful of the early
land animals...
Today
220m yrs ago
250k yrs ago
400m yrs ago
Scale of Life on Land
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...but about 65 million
years ago, a giant
meteor came crashing
down to earth...
Big
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First
Dinosaurs
First Life
on Land
...and the dinosaurs
were no more!
Dinosaurs Disappear
Today
67m yrs ago
250k yrs ago
220m yrs ago
400m yrs ago
Scale of Life on Land
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This left a new class of animals dominant on the land.
MAMMALS!
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Over time, a particular
group of mammals
emerged that lived in
trees.
To survive in that
environment, these
mammals needed 3D
vision and large brains to
process visual
information. They also
needed hands that could
grip with precision.
(Imagine living in a tree
without any of these.
You’d fall out!)
These mammals were the
first PRIMATES.
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Then, about 7 million years ago in Africa, a
branch of those primates became the first to
stand upright.
These were the first HOMINIDS. Different
hominids lived on earth over the next 7 million
years, some at the same time as others, but only
one survives to this day...
US!!!
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First
Hominids
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Dinosaurs
Disappear
The earliest hominids
lived in small, familysized groups. They
gathered plants, insects,
and small animals, and
they occasionally
scavenged the meat of
larger animals killed by
predators.
7m yrs
ago
250k yrs ago
Today
67m yrs ago
Scale of Life after the Dinosaurs
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Today
4 – 1.5m yrs ago
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Australopithecines
250k yrs ago
7m yrs ago
First
Hominids
The first hominids had
brains about the size of
a modern chimp’s. Over
time, new species
developed ever-larger
brains, and they began
to make more and more
complex tools. The
Australopithecines
likely used sharp sticks
to dig for food...
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...while Homo habilis
hominids, a later
species, were able to
make stone tools. They
chipped ‘flakes’ of
stone from large rocks
and used those flakes
as knives. They also
used the leftover ‘core’
to scrape out hides and
do other jobs.
Homo habilis
Today
250k yrs ago
2.4 – 1.6m yrs ago
1.5m yrs ago
4m yrs ago
Australopithecines
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Homo erectus
Today
1.8m – 27k yrs ago
250k yrs ago
2.4m yrs ago
1.6m yrs ago
1.5m yrs ago
Homo habilis
Australopithecines
4m yrs ago
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Homo erectus hominids,
which lived on Earth for
almost two million
years, were probably
the first ones who could
control and use fire.
They were also
the first to leave Africa.
Their fossils have been
found as far away as
China and Java (in
modern Indonesia).
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Social relationships
among our ancestors
were complex. Like
modern chimpanzees,
early hominids must
have been quite clever,
with a great deal of
social cooperation and
group politics. They
cared for each other,
especially their children.
WOW! These
early ancestors
of ours sound a
lot like us!
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Well, in some ways
that’s true – but this
species was different in
many other respects
from our species. We
have no evidence, for
example, that they had
art, religion, or
language.
ART
RELIGION
LANGUAGE
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So, what’s so
special about
us? What
makes us
HUMAN, and
how did we
BECOME
human?
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Well, you’ll just have
to wait for BIG ERA
TWO to get the
answer to those
questions!
End of Big Era One
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