Chapter 25, 27

The History of Life on Earth, Origin of Life, Procaryotes

February 11, 2011

The History of Life on Earth: Chapter 25

Fungi

EUKARYA

Trypanosomes

Green algaeLand plants

Red algae

ForamsCiliates

Dinoflagellates

Diatoms

Animals

AmoebasCellular slime molds

Leishmania

Euglena

Green nonsulfur bacteria

Thermophiles

Halophiles

Methanobacterium

Sulfolobus

ARCHAEA

COMMONANCESTOR

OF ALLLIFE

BACTERIA

(Plastids, includingchloroplasts)

Greensulfur bacteria

(Mitochondrion)

Cyanobacteria

ChlamydiaSpirochetes

both are prokaryotic

eukaryotes

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

Stromatolites

Fig. 25-4j

Fossilized stromatolite

The oldest fossils, from the Australian rocks called the Apex Chert:

3.5 billion yr old

And the Gunflint Chert, 1.9 billion yr old. From north of Lake Superior

Meteorite contents witness ancient non-biological organic molecules

including molecules that form osmotically functional vesicles

Nonanoic acid

Polycyclic aromatic hydrocarbons

Fig. 25-3

(a) Simple reproduction by liposomes (b) Simple metabolism

Phosphate

Maltose

Phosphatase

MaltoseAmylase

Starch

Glucose-phosphate

Glucose-phosphate

20 µm

Fig. 25-7

Animals

Colonizationof land

Paleozoic

Meso-

zoicHumans

Ceno-zoic

Origin of solarsystem andEarth

ProkaryotesProterozoic Archaean

Billions of years ago

1 4

32

Multicellulareukaryotes

Single-celledeukaryotes

Atmosphericoxygen

Fungi

EUKARYA

Trypanosomes

Green algaeLand plants

Red algae

ForamsCiliates

Dinoflagellates

Diatoms

Animals

AmoebasCellular slime molds

Leishmania

Euglena

Green nonsulfur bacteria

Thermophiles

Halophiles

Methanobacterium

Sulfolobus

ARCHAEA

COMMONANCESTOR

OF ALLLIFE

BACTERIA

(Plastids, includingchloroplasts)

Greensulfur bacteria

(Mitochondrion)

Cyanobacteria

ChlamydiaSpirochetes

both are prokaryotic

eukaryotes

Cyanobacteria

Fig. 25-8

Fig. 25-7

Animals

Colonizationof land

Paleozoic

Meso-

zoicHumans

Ceno-zoic

Origin of solarsystem andEarth

ProkaryotesProterozoic Archaean

Billions of years ago

1 4

32

Multicellulareukaryotes

Single-celledeukaryotes

Atmosphericoxygen

Origin of the eucaroytes

Table 25-1

Table 25-1a

Table 25-1b