Smithsonian Museum of Natural History: The First half of The Paleozoic Era: Life In The Oceans

 It starts with life and life started in the vast shallow oceans that eventually dominated our cooling planet.  This period of natural history is told through a series of imagined giant aquariums where we can watch life in the seas evolve from the earliest multicellular "animals" (which look a lot like plants, a curious beginning for complex life) to forms much more recognizable like corals, and nautilus and ancient fish.  Each aquarium is also accompanied by a dimly lit display case full of fossils representing the creatures in the huge dioramas.

635,000,000 to 541,000,000 years ago || EDIACARAN

The Rise of Animals

Chamia, a common frond-like member of the Ediacaran biota.

541,000,000 to 485,000,000 years ago || CAMBRIAN

Diversity Burst Forth

The arrival of the Trilobite.  Trilobites lived and evolved--and sometimes mostly stayed the same through unknown though sands of species over a time period covering 180,000,000 years!  They are the first known creatures to have developed Ocular-sensory organs.  But unlike our circular water filled eyes, there first attempt at this modification of animal life was composted of quartz-like minerals and far from being able to focus and "see" things in the conventional understand of sight, there eyes only noticed brightness or the lack thereof.  Now you or I might think of what possible benefit could such near blindness afford these little creatures that spent their days foraging on the shallow ocean's floor?  The answer is surprising a lot.  You can imagine sensing a brightness above you all the day long, and suddenly and briefly it vanishes.  You freeze.  You wait.  Again there is a moment of darkness.  Now you know you are in mortal danger and quickly you burrow yourself beneath the sand, because that thing that cut off the light was very likely one of a species of apex carnivores filling the oceans at that time called Alominocaris.

485,000,000 to 419,000,000 years ago || ORDOVIAN to SILURIAN

Marine Variety Triples

I have fieldstones from Kentucky that I collected when I was there which have fossils very similar to these embedded in them.

Always a new version of Tilobite was evolving, adapting to the many micro-biomes as earth's size lent it to develop distinct climates across its surface.  Note how this species "eyes" are far more refined than those of its distant cousins.

419,000,000 to 359,000,000 years ago || DEVONIAN

Life Above, Below, And All Around

Lobe-finned bony fish (skull cast)

Gogonasus andrewae

from the Gogo Formation, Australia

Trilobite

Koneprusia sp.

Hamar Laghdad Formation, Morocco

Giant Nautilus