Why Might Fossils Of The Same Species Of Plant/animal Be Located On 2 Different Continents?

Breadth On maps, lines of longitude and latitude divide the earth up. The lines that run from east to w are chosen latitude. They start with a line right around the middle of the world called the equator. This is zero degrees latitude. As you go due north and south from this line, the numbers increase until you lot get to the Due north and South Poles at 90 degrees. Annihilation further south or due north of seventy degrees latitude is in the Polar Regions or the polar circumvolve. South Eastern Australia was 75 degrees south. And then, because they lived over a hundred million years ago, the dinosaurs we discover in South Eastern Commonwealth of australia are chosen polar dinosaurs.

How do nosotros know that Australia has drifted?
The continents we know today have drifted a long way from where they started as ane big continent called Pangea. But how can we tell that the continents started as a i large state mass and slowly moved apart? > click to encounter ABC Scientific discipline Continental Drift animation.

Rivers of ice, called glaciers, cut marks into rock with the boulders that they slowly elevate along with them. Ancient rocks, at present in the tropics, accept these marks on them. Glaciers can't form in the hot torrid zone, so these rocks must have one time been thousands of kilometers away in colder parts of Earth. Click here to read more about the > Floating Continent

Fossils from many millions of years agone also show that one large continent had once existed and then broken apart. The fossils of the same ancient plants and modest dinosaurs are found on different continents.

Did they cross the oceans to get at that place?
No. they didn't. Scientists have noticed that like plants and animals have left fossils on country masses separated by big oceans. Exactly the same animate being or plant can't have evolved on unlike continents. Studies besides showed that the shape of the continents fit roughly together like a jigsaw puzzle and the rocks on one edge match the rocks on the other.

The trouble with this idea was that for a long time no-i could explain how the continents moved and and so evidence it. Eventually, some scientists came up with a theory called Plate Tectonics. To read more detail virtually Plate Tectonics, click here.

The continents are moving around on huge plates that are slowly pushed up from under the bounding main and crushed underneath mountain ranges. The sea floor spreads and moves the continents apart. But how did they evidence information technology? Get-go you lot have to understand a fiddling bit about magnetism.

Magnetism
The Earth is similar an enormous magnet. The reason that compasses point N is that compasses take magnets in them that are attracted to the bigger magnet of Globe. If you call up of the Globe as a big magnet you tin imagine the tiny magnet in a compass existence attracted to the opposite cease of the large magnet that is Earth. This contrary end is the N Magnetic Pole. And so a compass always points North.
But the foreign thing is that if you went back in time nearly a one-half a million years your compass would point Southward.

Shifting poles
For reasons that no-one fully understands, the Earth's magnetic poles slowly get weaker and so completely change, on average, every one-half a million years or so. Right now we are in the time of the magnetic field getting weaker and it's predicted that the poles will reverse over again some time in the next grand years.

But how tin can we tell that the magnetic poles accept reversed in the distant past?
Certain types of stone become magnetised when they are formed. Molten rock is imprinted with the magnetic field of the moment when it cools. It's a flake like a photograph capturing the lite of 1 moment in fourth dimension. The stone takes a magnetic photograph at the moment information technology cools down. If information technology'due south heated up and cooled again, the magnetism will alter to the magnetic field at that detail moment. At beginning, scientists were confused past the magnetism in ancient rocks pointing in the opposite direction, only came to realise that all the rocks of a certain age, all over the earth, showed the same management, proving that the Earth's magnetic poles sometimes completely reverse.

Magnetic strips on the sea floor
Once scientists knew about the changing of Globe's magnetic poles, they could piece of work out how many times information technology had happened and when. The theory of continents being pushed apart could be proved if the magnetism recorded in the rocks showed that molten rock was spreading away from the cracks in both directions. The last time that the poles were reversed was half a one thousand thousand years ago. The rocks on both sides of the crack, at the altitude they should have moved in a half a 1000000 years, should have the same sort of magnetism. And they exercise. If yous get farther back to the previous fourth dimension the poles reversed and look further away on either side of the ridge, again you find strips of stone that record the contrary polarity. The continents actually are moving and it'south been recorded by strips of different magnetism in the rocks on the sea flooring.

Check out these ABC sites for more information on Pole Shifting

Journey to middle of pole-shifting World
" Latest computer simulations of the Earth's deep interior, provide insights into the performance of the 'geodynamo' and the occasional reversal of Globe's magnetic field…"
https://www.abc.net.au/science/news/stories/s101783.htm

Flipping over the Sun
American enquiry has constitute a reason why the Sun flips its magnetic poles every eleven years.
https://www.abc.net.au/science/news/space/SpaceRepublish_574458.htm

Source: https://www.abc.net.au/science/ozfossil/ageofreptiles/continental/default.htm

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