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What Took So Long...evolutionarily?

 
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jabailo



Joined: 20 Mar 2006
Posts: 1273
Location: Kent (East Hill), WA

PostPosted: Fri Jul 29, 2011 8:30 am    Post subject: What Took So Long...evolutionarily? Reply with quote

In a recent discussion that included the publishers of YRIHF, the topic of the long time periods in evolution came up. Now, it is typical for professors to speak on the long, slow early periods of evolution, single celled organisms, fish and so on leading the very recent and rapid evolution of hominids and human intelligence...letting the audience gasp as billions turn into millions turn into hundreds of thousand then tens of thousands of years. It seems that evolution happened like a roller coaster, slowly being pulled up a long hill, then reaching a peak and then falling, faster and faster until it reaches the bottom and rolls along at grade...fast but seemingly at equilibrium.

However, I ask, instead of being amazed at recent "giant steps" in evolution, why not ponder why it took so, so long for many of the initial phases to occur. The other puzzle is that for earlier, smaller organisms, there are high birth rates and fast reproductive cycles. It would seem that a unicellular organism would have way more chances to create variations and that many of these should survive by sheer numbers. Doesn't that make evolution happen "faster" ?


From The Major Transitions in Evolution.:

Major Evolutionary Transitions

Quote:
the authors considered to be key transtions in evolution. They are as follows:

replicating molecules ==> populations of molecules in compartments
independent replicators ==> chromosomes
RNA ==> DNA and Protein
prokaryotes ==> eukaryotes
asexual clones ==> sexual populations
protists ==> animals, plants, fungi
solitary individuals ==> colonies
primate societies ==> human societies

[...]

Another critical step in the evolution of life, was the transition from prokaryotes to eukaryotes. The prokaryotes originated about 3.5 to 4 billion years ago. The eukaryotes, on the other hand, originated only about one billion years ago. Why did it take so long for eukaryotes to evolve?


http://webspace.webring.com/people/je/exobiology/Origins/transitions.html
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