GEOL 11042 Lecture Notes - Lecture 15: Red Color, Jack Hills, Endosymbiont
8 Nov 2020
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Sun, rocky inner planets (mercury, venus, earth, mars) with heavier elements, and outer planets composed of lighter elements (jupiter, saturn, uranus, neptune). Precambrian timescale is divided into two eons for which we have rocks on earth: the. Archean eon (dating from about 3. 8 billion years ago to about 2. 5 billion years ago) and the proterozoic eon (dating from about 2. 5 billion years ago to about 0. 5 billion years ago). The hadean eon is represented only by those jack hills zircons, which are 4. 2 to. 4. 4 billion years old, having eroded out of ancient rocks now long gone. If so, what kind of life was it: there is evidence, and it is of two types: fossilized bacteria and archea (collectively, microbes) and chemical traces of their activity. The cell wall is complex, and contains folded membranes: these prokaryotes made their living through fermentation and photosynthesis. The photosynthetic ones were cyanobacteria (known as blue-green algae).
