The first vertebrates were deceptively short!
While they might have appeared to be about six to eight inches in length, the truth is that they were much shorter- probably no more than just two or three inches (from tip to tail). But, no one knows for sure!
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.
Vertebrates first appeared during the Paleozoic era.
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.
No. The 1st vertebrates appeared in the fossil record about 525 million years ago during the Cambrian Period. This was in the Paleozoic Era.
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The first land vertebrates appeared in the: Devonian
The first vertebrates appeared during the Cambrian period, approximately 525 million years ago. These early vertebrates were jawless fish, known as agnathans, which marked a significant evolutionary development in the animal kingdom. Fossil evidence, such as the discovery of the extinct genus Myllokunmingia, supports this timeline and highlights the emergence of complex structures in early vertebrates.
D.Sponges
Long eared jerboas, a type of small rodent, are mammals, and all mammals are vertebrates.
Fish
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