The History of Life on Earth, Origin of Life, Procaryotes Chapter 25, 27 The History of Life on Earth, Origin of Life, Procaryotes February 11, 2011 For origin and early life see http://rst.gsfc.nasa.gov/Sect20/A12c.html

The History of Life on Earth: Chapter 25

eukaryotes both are prokaryotic EUKARYA BACTERIA ARCHAEA Land plants Dinoflagellates Green algae Forams Ciliates Diatoms Red algae Amoebas Cellular slime molds Euglena Trypanosomes Animals Leishmania Fungi Sulfolobus Green nonsulfur bacteria Thermophiles (Mitochondrion) Figure 26.21 The three domains of life, supported by the sequence from many sequenced genomes Spirochetes Halophiles Chlamydia COMMON ANCESTOR OF ALL LIFE Green sulfur bacteria BACTERIA Methanobacterium Cyanobacteria both are prokaryotic ARCHAEA (Plastids, including chloroplasts)

From Two Kingdoms to Three Domains Recently, based on phylogenetic analysis: the three domain system has been adopted: the domains are Bacteria, Archaea, and Eukarya. So how did it all start, how long ago did it start, and then what happened?

The First Single-Celled Organisms The oldest known fossils are stromatolites, rock-like structures composed of many layers of bacteria and sediment Stromatolites date back 3.5 billion years ago Prokaryotes were Earth’s sole inhabitants from 3.5 to about 2.1 billion years ago

Fig. 25-4i Figure 25.4 Documenting the history of life Stromatolites

Fossilized stromatolite Fig. 25-4j Figure 25.4 Documenting the history of life Fossilized stromatolite

The oldest fossils, from the Australian rocks called the Apex Chert: And the Gunflint Chert, 1.9 billion yr old. From north of Lake Superior http://rst.gsfc.nasa.gov/Sect20/A12c.html 3.5 billion yr old

Meteorite contents witness ancient non-biological organic molecules

including molecules that form osmotically functional vesicles Nonanoic acid On polycyclic aromatic hydrocarbons: http://www-space.arc.nasa.gov/~astrochm/PAHs.html Deamer (1999) extracted the water-soluble portion of a carbonaceous chhhondrite (meteorite) and yielded the bilayer membrane vesicles at the top, which are 10-50 um in diam and are a micture of the two molcule types pictured. The bilayer is resistant to ion flux. Deamer: amphiphilic compounds capable of membrane formation are present in carbonaceous meteorites and are able to self-assemble into bilayer membranes. … the observation that membranes can self-assemble from the amphiphilic components at least makes it more plausible that membrane-bounded structures were present at the time of life's origin. Polycyclic aromatic hydrocarbons

(a) Simple reproduction by liposomes Maltose (b) Simple metabolism Fig. 25-3 20 µm Glucose-phosphate Glucose-phosphate Phosphatase Starch Amylase Phosphate Maltose Figure 25.3 Laboratory versions of protobionts (a) Simple reproduction by liposomes Maltose (b) Simple metabolism

Ceno- zoic Meso- zoic Humans Paleozoic Colonization of land Animals Fig. 25-7 Ceno- zoic Meso- zoic Humans Paleozoic Colonization of land Animals Origin of solar system and Earth 1 4 Proterozoic Archaean Prokaryotes Figure 25.7 Clock analogy for some key events in Earth’s history Billions of years ago 2 3 Multicellular eukaryotes Single-celled eukaryotes Atmospheric oxygen

eukaryotes both are prokaryotic EUKARYA BACTERIA ARCHAEA Land plants Dinoflagellates Green algae Forams Ciliates Diatoms Red algae Amoebas Cellular slime molds Euglena Trypanosomes Animals Leishmania Fungi Sulfolobus Green nonsulfur bacteria Thermophiles (Mitochondrion) Figure 26.21 The three domains of life, supported by the sequence from many sequenced genomes Spirochetes Halophiles Chlamydia COMMON ANCESTOR OF ALL LIFE Green sulfur bacteria BACTERIA Methanobacterium Cyanobacteria both are prokaryotic ARCHAEA (Plastids, including chloroplasts)

Cyanobacteria

Fig. 25-8 Figure 25.8 Banded iron formations: evidence of oxygenic photosynthesis For the Discovery Video Early Life, go to Animation and Video Files.

Ceno- zoic Meso- zoic Humans Paleozoic Colonization of land Animals Fig. 25-7 Ceno- zoic Meso- zoic Humans Paleozoic Colonization of land Animals Origin of solar system and Earth 1 4 Proterozoic Archaean Prokaryotes Figure 25.7 Clock analogy for some key events in Earth’s history Billions of years ago 2 3 Multicellular eukaryotes Single-celled eukaryotes Atmospheric oxygen

Table 25.1

Origin of the eucaroytes

Table 25-1 Table 25.1

Table 25-1a Table 25.1

Table 25-1b Table 25.1