Fish
Fossils across Geologic Time and Evolution
We
learn in biology 101 that the cytoplasm in our cells bears
fairly close resemblance to that of seawater. This is testament
that life began in the sea, and a legacy of our evolutionary
heritage that began with the earliest marine vertebrates
more one half billion years ago. It’s been a very long
run for us eukaryotic life forms, considering we are really
just
guests
on a planet owned prokaryotes. The evolutionary history of
fishes began some 530 million years ago during a period of
earth
where macroscopic animals burgeoned
in diversity. The period is often called the Cambrian Explosion
because it truly was an unprecedented period when new forms
appeared, adapted, speciated and, some, and some ending as
failed experiments that did not persist.
Because
fish
systematics and classification is most complicated, this
site is organized by grouping fishes into five major groups:
1) Jawless fishes; 2) Armored fishes †; 3) Cartilaginous
fishes; 4) Ray-finned fishes; and 5)
Lobe-finned fishes, all within Phylum Chordata and subphylum Vertebrata. Of the
five clades, only the armored fish are extinct.
