from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of or relating to the geologic time period from approximately 570 million years ago to the present, comprising the Paleozoic, Mesozoic, and Cenozoic eras, and marked by an abundance of fossil evidence of life, especially higher forms, in the corresponding rocks. See Table at geologic time.
- n. The Phanerozoic Eon.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Of, or relating to the geologic eon from about 570 million years ago to the present; comprises the Paleozoic, Mesozoic and Cenozoic eras.
- proper n. The Phanerozoic eon.
from The Century Dictionary and Cyclopedia
- Of or pertaining to animals that live in places that are exposed to the daylight.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the period from about 5,400 million years ago until the present
The term Phanerozoic can also describe the assumption that environmental law begins and ends with protection of only those things visible to the naked human eye.
(The Phanerozoic is the last 530 million years of geologic history, when there's an abundant fossil record of multicellular creatures with hard parts -- bones, shells, and so on -- that can fossilize.)
“Most evolutionary biologists deal with the Phanerozoic, which is like saying that history began in 1909 when the Ford Motor Company opened shop in Dearborn, Mich,” Margulis quipped.
It took three billion years for multicellularity to evolve (a strong argument for its unlikelyhood), but once it did, it initiated an evolutionary "arms race" that resulted in the "Cambrian explosion" (which should really be called the "Phanerozoic explosion", as it only began in the Cambrian, but continues to the present).
However, almost as soon as multicellularity arose, it "exploded", producing the fantastic diversity of multicellular animals, plants, and fungi that we see today and in the fossil record of the Phanerozoic.
There have been so many events, and so many of them depend on when they occur in the time sequence, and so many of them are effectively "random" (i.e. uncorrelated) with respect to each other, that the probability of getting the same outcome with each iteration of the Phanerozoic asymptotically approaches zero.
The Edenic Period spans the Paleozoic and Mesozoic periods of geologic time as well as the Paleogene, Miocene, Pliocene epochs and the preponderance of the Pleistocene; the Edenic Period is generally an overlap with the Phanerozoic, except that the Edenic Period is defined to have ended in the late Pleistocene prior to the Holocene.
Multicellular organisms ruled the planet during the eon known as the Phanerozoic.
This theory is put forward by paleontologist Ronald Martin of the University of Delaware: “Secular Increase in Nutrient Levels through the Phanerozoic; Implications for Productivity, Biomass, and Diversity of the Marine Biosphere,” Palaios 11 1996: 209–19.
It also marks another big step in the takeover of geochemical processes by living things: most Phanerozoic limestones are made of biological debris.
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