During the Paleozoic Era (542 to 248 million years ago), which is itself
divided into various periods (Cambrian, Ordovician, Silurian, Devonian,
Carboniferous, Permian), the first fish, and later amphibians, reptiles
and mammal-like reptiles, all appeared. At the the end of the
Paleozoic
Era, there was some terrible disaster (the "Permian mass extinction")
when many creatures became extinct.
Dinosaurs and other archosaurs (which means "ruling reptiles"),
including crocodiles and
Pterosaurs, first evolved in the Triassic period,
and were the dominant land creatures during the entire Mesozoic Era.
During the early part of Mesozoic Era,
the mammal-like reptiles
dramatically declined, apparently out competed by the
dinosaurs, however
they did give rise to the first mammals, which were mostly tiny mouse-size
creatures.
The chart below shows possible relationships between the main groups of vertebrates:
(to see how different
types of dinosaurs are related to each other,
please see
dinosaur classification).
Note: This diagram is greatly simplified, based in part on speculation, and
the depicted dates of branches/evolutionary-splits and extinctions
may not always be exactly correct.
Although this site is run on a commercial basis,
we do hope it will be useful and interesting for students and teachers.
We welcome people linking to this website, or citing us in their school and educational projects
(remember in school projects and papers, you should always cite your sources).
CERTAIN CONTENT THAT APPEARS ON THIS SITE COMES FROM AMAZON SERVICES LLC. THIS CONTENT IS PROVIDED 'AS IS' AND IS SUBJECT TO CHANGE OR REMOVAL AT ANY TIME.
Disclosure:
Our company's websites' content (including this website's content) includes advertisements for
our own company's websites, products, and services,
and for other organization's websites, products, and services.
In the case of links to other organization's websites,
our company may receive a payment, (1) if you purchase products or services,
or (2) if you sign-up for third party offers, after following links from this website.
Unless specifically otherwise stated, information about other organization's products and services,
is based on information provided by that organization,
the product/service vendor, and/or publicly available information - and should
not be taken to mean that we have used the product/service in question.
Additionally, our company's websites contain some adverts which we are paid
to display, but whose content is not selected by us, such as Google AdSense ads. For more
detailed information, please see Advertising/Endorsements Disclosures
