Transcript Rights v. responsibilities

How did life emerge
By
Crby cr steussy
Most material from CS Brown’s
“Big History”
Earth
• About 4.6 bil yrs ago
a supernova
exploded in the
Milky Way
• From the debris our
star, the sun, and
planets, including
earth appeared.
Earth
• About 4 billion years
ago as the earth
cooled bubbles
formed in the molten
lava
Early Earth
• From 3.8 to 1.8
billion years ago a
sort of blue-green
bacteria spread
across the cooling
earth.
• The first form of life.
Early Earth
• The earliest cells
(right) had no nuclei.
• eukaryotic cells with
nuclei began about
1.9 billion years ago
• The “Goldilocks
conditions”
not so- Early Earth
• Around 600 Million
(with an M) the first
soft tissues sea
creatures, about the
width of 5 human
hairs, appeared.
• Goldilocks
conditions
not so- Early Earth
• Between 400-600
Million years ago
animals with “hard
parts” like trilobites
emerged, as did plants
and something like a
sow bug (right) crawled
from the sea.
• The so-called
“Cambrian explosion”
not so- Early Earth
• Around 250 million
years ago a mass
extinction occurred.
• Fungus ruled the
earth of pangea
afterwards
not so- Early Earth
• 200 million years
ago reptiles
appeared that
evolved into
dinosaurs
• Flowering plants
and hardwood trees
emerged 100 million
years ago
Earth
• Around 65 million
years ago a massive
asteroid impact
caused the
extinction of the
dinosaurs.
• In its wake
mammals began to
flourish