Origins of Life On Earth
Further information: Evidence of common descent, Common descent, and Homology (biology)Biologists reason that all living organisms on Earth must share a single last universal ancestor, because it would be virtually impossible that two or more separate lineages could have independently developed the many complex biochemical mechanisms common to all living organisms. As previously mentioned the earliest organisms for which fossil evidence is available are bacteria, cells far too complex to have arisen directly from non-living materials. The lack of fossil or geochemical evidence for earlier organisms has left plenty of scope for hypotheses, which fall into two main groups: 1) that life arose spontaneously on Earth or 2) that it was "seeded" from elsewhere in the Universe.
Read more about this topic: Evolutionary History Of Life
Famous quotes containing the words origins of, origins, life and/or earth:
“The origins of clothing are not practical. They are mystical and erotic. The primitive man in the wolf-pelt was not keeping dry; he was saying: “Look what I killed. Aren’t I the best?””
—Katharine Hamnett (b. 1948)
“Grown onto every inch of plate, except
Where the hinges let it move, were living things,
Barnacles, mussels, water weeds—and one
Blue bit of polished glass, glued there by time:
The origins of art.”
—Howard Moss (b. 1922)
“There was never a revolution to equal it, and never a city more glorious than Petrograd, and for all that period of my life I lived another and braved the ice of winter and the summer flies in Vyborg while across my adopted country of the past, winds of the revolution blew their flame, and all of us suffered hunger while we drank at the wine of equality.”
—Norman Mailer (b. 1923)
“Do you know the balancings of the clouds, the wondrous works of the one whose knowledge is perfect, you whose garments are hot when the earth is still because of the south wind? Can you, like him, spread out the skies, hard as a molten mirror?”
—Bible: Hebrew, Job 37:16-18.
One of Job’s “comforters,” of God.