Slime Molds - The first protist fossils occur in rocks...

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Slime Molds: Myxomycota Slime molds are often classified as fungi , although now most specialists consider them a group of protistans. In fact, slime molds do not forma monophyletic group, and will have to be subdivided in some future classification scheme. Slime molds are not closely related to other groups of plants or animals. Slime molds, which spend part of their life as single-celled forms, can aggregate to form multicellular forms. They thus may represent a transition between unicellular and multicelluar forms, the second major advancement after the evolution of eukaryotic cells. Figure 26 illustrates some of the stages of a plasmodial life history. The Fossil Record
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Unformatted text preview: The first protist fossils occur in rocks approximately 1.2-1.4 billion years old from the Bitter Springs Formation in Australia. However, some paleobiologists doubt that these small (a mere 5 micrometers in diameter) cells are actually eukaryotic. An older group of eukaryotic microfossils (perhaps dating back as far as 1.8 billion years ago) are the acritarchs. Many "algae" produce resting cysts that resemble acritarchs. Multicellular protists appeared in the fossil record more than 600 million years ago. Some problemmatic fossils, thought by some paleobotanists to be algae, have been found in rocks approximately one billion years old....
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This note was uploaded on 11/29/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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