Jurassic era, 195 -136
Ago - MYA
Antarctica had been a part of "Gondwanaland"
(an ancient super continent that was breaking up and doesn't exist any more)
for about 200 million years.
consisting of Africa, Antarctica, Australia, India and New Zealand begins
to break up
Dinosaurs rule the world
and have done for nearly 30 million years
First flowering plants
First mammals and birds
appeared - but dinosaurs still rule
The South Atlantic is
born as Gondwanaland breaks up
The idea that continents are not fixed in
position or size and wander about across the globe is known as Plate
Tectonics. It was noticed long ago that the west coast of Africa and
east coast of South America fit together quite nicely (ignoring a few thousands
of miles of ocean in between).
and other evidence was put into a theory by a chap called Alfred Wegener
in 1912. Like many theories that challenge the accepted view of things,
he wasn't taken seriously at first.
the 1960's and 1970's however, the theory had become accepted due to
new evidence about magnetism on the sea floor (terribly complicated stuff
- you don't want to know about it now).
view is now that the earth is made up of plates, some are land plates,
some are ocean plates. They fit together like the patches making up a football
- except that there's less of them and they don't stay in the same place,
they wander around over the football (earth), and they're not all the same
size, and they're bigger than the patches on a football, and some are land
while some are sea (Oh sorry I said that already). But apart from those
exactly like a football.
Scientists are able to find out what the
climate was like in different parts of the world in the past mainly through
the fossils of plants and animals that are found in the rocks of known age.
Corals means the climate was warm, woolly rhinoceros mean that the climate
was cold - for instance.
Not as exciting, but plant pollen grains
can give a lot of information about the types of plants and therefore
the climate at various times in geological history.
clever stuff like oxygen isotopes and chemical data found in rocks from
lava flows (like a snap-shot at the time it solidified) also add to the
Cretaceous era 136 - 65 MYA
forests cover Antarctica made up largely of ferns and conifers (flowering
plants such as most trees that we recognize today had only just evolved
and hadn't got very far yet)
Australia and New Zealand split from Antarctica,
Antarctica goes it alone.
Antarctica enjoys a semi-tropical climate,
continues to drift south.
Rocky mountains rise
in North America
First placental mammals
- mammals that give birth to live young (earlier ones laid eggs like duck
billed platypus and echidnas)
65 MYA an asteroid strikes
the earth off the coast of Yucatan, Mexico - some think that this killed off the dinosaurs, others think
they were on the way out anyhow. Dinosaurs don't rule anymore - mammals
Eocene era 54 - 38 MYA
Much geological activity as the Trans
Antarctic mountains are uplifted from sea level cutting across Antarctica
from coast to coast.
The first large ice caps form as Antarctica
settles its position over the south pole
like animals, rhinoceroses, ruminants, and the ancestors of elephants
penguins evolve from flying birds
Miocene era 26 - 7 MYA
The whole Antarctic continent
becomes covered in ice.
The Antarctic convergence
arises. This circumpolar upwelling of deep oceanic waters essentially
isolates the southern ocean from the South Atlantic, Indian and Pacific
oceans and has a great effect on keeping Antarctica cold. It also means
that many sea creatures cannot migrate north or south across the convergence.
Seals all over the place.
whales evolve from land-dwelling insectivorous ancestors
Pliocene era 7 - 0 MYA
2 - 5 MYA
Fossilized plant remains
found from this period, imply that the ice sheets have advanced and
melted many times over the ages.
4 MYA first Hominids
(human like creatures) arise
Homo sapiens, 200,000
years ago? maybe as little as 50,000 years ago