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There are two main theories on this. The first is that they were made approximately 4,000 or 5,000 years ago--these were sea mammals.
The other theory says that they evolved over millions of years from protozoa-type things so the first vertebrates were probably frog-like creatures according to this theory.
What else can I help you with?
Earth's first vertebrates appeared during this period?
No, the first vertebrates evolved long before the Mesozoic. The first vertebrates, small jawless fish, evolved around 520 million years ago. Land animals had even evolved long before the Mesozoic Era.
How long ago did the first dinosaurs appear?
About 230 million years ago.
Did the first vertebrates evolve during the mesozoic era?
No. The 1st vertebrates appeared in the fossil record about 525 million years ago during the Cambrian Period. This was in the Paleozoic Era.
How long ago did mans first ancestor appear?
on the 12th of march
How long ago did arthropods first appear?
Around 400 million years ago, in the Devonian, the age of sharks and early amphibians.
When did numbers as we know them first appear?
A Long...Long....Long....Long......Long....Long.....Long...Long.......Long.....Long....Long..Long Time Ago XD
About how long ago did australopithecus's appear?
they lived about 3 millon years ago. : )
When did fungus first appear?
a while ago
How long ago did Neanderthal appear?
Completely evolved Neanderthals appeared 130,000 years ago.
When did SpongeBob first appear on tv?
3 years ago
When did macromolecules first appear?
3.5 billion years ago .
During what period did the first vertebrates appear?
The first vertebrates evolved during the Cambrian Explosion about 525 million years ago. The Cambrian Explosion, obviously, occurred during the Cambrian period. The Cambrian period was part of the Paleozoic era.
