(2) Earth Home

Plenty of time has passed to allow for all this unfolding of natural
systems. Perched on the outer rim of the Milky Way galaxy,
scientists believe that the Earth is around 4.55 billion-years-old.
Paleontologists have labeled historical periods going back close
to the emergence of the planet. There's the Precambrian period,
in which the earliest fossils dated back anywhere from 4.0 to 2.5
billion years ago--such as bacteria and stromatolites. Algae made
their appearance between 2.5 billion years and 570 million years
ago. Multi-celled animals were present some 700-600 million
years ago.

The Phanerozoic period dates from 570 million years to the
Present. First there were the molluscs, later jawless fish, then
jawed fish. Sharks have been around a long time, still quite
primitive. Marine reptiles, dinosaurs, modern fish, birds, and
mammals came upon the scene.

Primates came around between 65-56 millions years ago, and later
rodents, whales, and horses show themselves some 56-to-34
million years back. And Hominids walked across the land between
24-to-5 millions years ago. Eventually Australopithecus showed-up
between 5 and 1.8 million years ago. And, finally, Homo took the stage
some 1.8-to 0.01 million years back--along with mastodons and
mammoths.

Some of these life forms are gone, some are still here, and as we all
know, "Homo" went through stages of development, some forms gone
(like the Neanderthal), and eventually the big-brained Homo Sapiens
ruled the Earth.

I could go on and on about all these different Periods mentioned
above, even discussing a breakdown of these into different eras.
I could go into fine detail about all these specific developments,
but my little journal about my pilgrimage is not the place for such.
Maybe after I decide that I have gone as far as I can in my
pilgrimage, then perhaps I'll write a detailed book--or two or
three--about all this.