Download Prokaryotes

CHAPTER 15
The Evolution of Microbial Life
張學偉 助理教授 生物醫學暨環境生物學系
http://genomed.dlearn.kmu.edu.tw
[email protected]
PowerPoint® Lecture Slides for
Essential Biology, Second Edition & Essential Biology with Physiology
Neil Campbell, Jane Reece, and Eric Simon
Presentation prepared by Chris C. Romero
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The number of bacteria
in one human’s mouth
is greater than the total
number of people who
ever lived
• Each year more than 200
million people become
infected with malaria
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• Bacterial fermentation is
used to produce cheese,
yogurt, buttermilk, and
many types of sausage
• More than half of our antibiotics
come from soil bacteria of the
genus Streptomyces
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BIOLOGY AND SOCIETY:
BIOTERRORISM
• During the fall of 2001, five Americans died from
the disease anthrax in a presumed terrorist attack
Figure 15.1
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• Animals, plants, fungi, and viruses have all
served as weapons, but the most frequently
employed biowarfare agents have been bacteria.
參考來源-美國公共電視
History of Biowarfare (177K)
Requires Flash
[http://www.pbs.org/wgbh/nova/bioterror/history.html#]
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• History for useing biological agents as weapons
– The practical difficulties of controlling such
weapons—and a measure of ethical repugnance—
led the United States to end its bioweapons program
in 1969 and to destroy its products
– Although not all signatories have honored it, 103
nations have signed the Biological Weapons
Convention, pledging never to develop or store
biological weapons
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• Not all bacteria are harmful to humans
– Nearly all life on Earth depends on bacteria and
other microbial life in one way or another
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MAJOR EPISODES IN THE
HISTORY OF LIFE
Prokaryotes
Eukaryotes
Protists
Bacteria Archaea
Plants
Fungi
Animals
Cenozoic First humans
Mesozoic Extinction of dinosaurs
475 - Paleozoic Plants and symbiotic
fungi colonize land
570 -
Oldest animal fossils
1,000 -
Origin of multicellular
organisms
1,700 -
Oldest eukaryotic
fossils
Precambrian
Accumulation of atmospheric
oxygen from photosynthetic
cyanobacteria
Oldest prokaryotic fossils
Earth cool enough for crust to solidify
Origin of Earth
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Figure 15.2
•Earth was born 4.5 billion years ago
• Prokaryotes
– Appeared about 3.5 billion years ago
• Oxygen production
– Began about 2.5 billion years ago
• Single-celled eukaryotic organisms
– Evolved about 1.7 billion years ago
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• Multicellular eukaryotes
– Evolved about 1 billion years ago
• All the major phyla of animals
– Evolved by the end of the Cambrian explosion,
which began about 570 million years ago
• About 475 million years ago
– Plants and fungi colonized land
– Amphibians evolved from fish, and vertebrate life moved
onto land
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THE ORIGIN OF LIFE
• We may never know how life began on Earth
Resolving the Biogenesis Paradox
• All life today arises by the reproduction of
preexisting life, or biogenesis
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• Most biologists now
think it is possible that
chemical and
physical processes
on the early Earth
produced simple cells
Figure 15.3
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A Four-Stage Hypothesis for the Origin of Life
Inorganic compounds
1
• According to one
hypothetical scenario,
the first organisms were
products of chemical
evolution in four stages.
Abiotic synthesis
Organic monomers
2 Polymerization
Polymer
3 Self-replication
Complementary chain
4 Packaging
Membrane-enclosed compartment
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Visual Summary 15.2
Stage 1: Abiotic Synthesis of Organic Monomers
• Stanley Miller
– Devised an experiment
that produced small
organic molecules in
1953
Figure 15.4
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Stage 2: Abiotic Synthesis of Polymers
• Researchers have observed polymerization of
organic monomers in various situations
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Stage 3: Origin of Self-Replicating Molecules
• Laboratory experiments have shown that short
RNA molecules can assemble spontaneously
Original “gene”
RNA monomers
Formation of
short RNA
polymers: simple
“genes”
Assembly of a
complementary
RNA chain
(pairing rules are
G with C and A
with U)
Complementary
chain serves as
template for
making
copy of original
“gene”
Figure 15.5
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Stage 4: Formation of Pre-Cells
• The properties of life
emerge from an
interaction of molecules
organized into higher
levels of order
Self-replication
of RNA
RNA
Self-replicating
RNA acts as
template on
which
polypeptide
forms
Polypeptide
Polypeptide
acts as
primitive
enzyme
that aids
RNA
replication
Membrane
Polypeptide
Figure 15.6
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• Laboratory experiments demonstrate that precells could have formed spontaneously from
abiotically produced organic compounds
Cooling polypeptide
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liposome
Figure 15.7
From Chemical Evolution to Darwinian Evolution
• Over millions of years
– Natural selection favored the most efficient
pre-cells
– The first prokaryotic cells evolved
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Prokaryotes
• Prokaryotes
– Lived and evolved all alone on Earth for 2 billion years
1-10mm: most prokaryotes size; 10-100 mm: most eukaryotes
Fossilized
prokaryotes
Figure 15.8
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They’re Everywhere!
• Prokaryotes
– Are found wherever there is life
– Outnumber all eukaryotes combined
– Can cause disease
– Can be beneficial
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The Two Main Branches of Prokaryotic
Evolution: Bacteria and Archaea
• The majority of prokaryotes are bacteria.
• Prokaryote
=
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Bacteria
• Some archaea are
“extremophiles”
– Extreme
halophiles
thrive in salty
environments
Figure 15.9
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• Extreme thermophiles
– Inhabit very hot water
• Methanogens
– Inhabit the bottoms of lakes and swamps
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The Structure, Function, and Reproduction
of Prokaryotes
• Prokaryotic cells
– Lack nuclei (called nucleoid)
– Lack other membrane-enclosed organelles
– Have cell walls exterior to their plasma
membranes
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• Prokaryotes
come in several
shapes
– Cocci
– Bacilli
– Spirochetes
Figure 15.10
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• Most prokaryotes are unicellular and very small
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• Some prokaryotes
– Form true colonies
– Show
specialization of
cells
– Are very large
Figure 15.11
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• About half of all
prokaryotes are
motile, using
flagella
Plasma
membrane
Cell wall
Rotary movement of each flagellum
Figure 15.12
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• Some prokaryotes
– Can survive extended periods of very harsh
conditions
– Form endospores
Figure 15.13
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• Most prokaryotes can reproduce by binary
fission at very high rates if conditions are
favorable
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The Nutritional Diversity of Prokaryotes
• Prokaryotes exhibit four major modes of nutrition
Table 15.1
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• Photoautotrophs
– Are photosynthetic organisms
– Include the cyanobacteria
• Chemoautotrophs
– Need CO2 as a carbon source
– Extract energy from inorganic substances
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• Photoheterotrophs
– Use light to generate ATP
– Must obtain their carbon in organic form
• Chemoheterotrophs
– Must consume organic molecules for both
energy and carbon
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The Ecological Impact of Prokaryotes
• Prokaryotes
– Have a major impact on the Earth and its
inhabitants
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Bacteria That Cause Disease
• Pathogens
– Are bacteria and other microorganisms that
cause disease
Figure 15.14
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• Most pathogenic bacteria
– Cause disease by producing poisons
• Exotoxins
– Are poisonous proteins secreted by bacterial
cells
• Endotoxins
– Are chemical components of the cell walls of
certain bacteria
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• The best defenses against bacterial disease are
– Sanitation
– Antibiotics
– Education
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• Lyme disease
– Is caused by
bacteria
carried by ticks
萊姆症(又稱萊姆關節炎,由扁蝨傳染,
症狀有紅斑、頭疼、發燒等等)
Figure 15.15
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Prokaryotes and Chemical Recycling
• Prokaryotes play essential roles
– In chemical cycles in the environment
– In the breakdown of organic wastes and dead
organisms
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Prokaryotes and Bioremediation
• Bioremediation is the use of organisms to
remove pollutants from water, air, and soil
– A familiar example is use of prokaryotic
decomposers in sewage treatment
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Rotating
spray arm
Rock bed coated with
aerobic bacteria
and fungi
Outflow
Liquid wastes
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Figure 15.16
• Certain bacteria can decompose petroleum and
are useful in cleaning up oil spills
Figure 15.17
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PROTISTS (單細胞生物)
• Protists
– Are eukaryotic
– Evolved from prokaryotes
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The Origin of Eukaryotic Cells
• Eukaryotic cells evolved through the
combination of two processes
1.Cell with nucleus and endomembrane system
2.Photosynthetic eukaryotic cell
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• In one process, the
eukaryotic cell’s
endomembrane
system evolved
from inward folds
of the plasma
membrane of a
prokaryotic cell
DNA
Plasma membrane
Cytoplasm
Ancestral
prokaryote
Endoplasmic
reticulum
Nuclear
envelope
Nucleus
(a) Cell with nucleus and
endomembrane system
Figure 15.18a
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• The second process, endosymbiosis,
generated mitochondria and chloroplasts
Aerobic heterotrophic prokaryote
Photosynthetic prokaryote
(Some cells)
Chloroplast
Mitochondrion
(b) Photosynthetic eukaryotic cell
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Figure 15.18b
The Diversity of Protists
• All protists are eukaryotes
– Most are unicellular
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Protozoans
• Protozoans
– Live primarily by ingesting food
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• Protozoans include
RBC
– Flagellates,
with flagella
(a) Trypanosomes (flagellates)
睡病蟲,錐體蟲
Figure 15.19a
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– Amoebas, with
pseudopodia
(b) An amoeba ingesting food
– Forams (有孔蟲)
(c) A foram
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Figure 15.19b,
– Apicomplexans(頂覆蟲)
(d) An apicomplexan: Plasmodium瘧原蟲
– Ciliates (纖毛蟲), with
cilia
(e) Paramecium
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Figure 15.19d, e
Slime Molds
• Slime molds (黴菌)
– Resemble fungi (真菌) in appearance and
lifestyle
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• Plasmodial slime molds
A slime mold (Physarum polycephalum), showing a creeping
mass of yellowish protoplasm called a plasmodium (變形體)
Figure 15.20
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• Cellular slime molds
– Have an
interesting and
complex life cycle
Sluglike colony
Amoeboid
cells
Reproductive
structure
reference
http://universe-review.ca/I10-09-slimemould1.jpg
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spore
Figure 15.21
Unicellular Algae
• Algae
– Are photosynthetic protists [單細胞生物]
– Are found in plankton (浮游生物總稱)
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• Unicellular algae include
– Dinoflagellates (二鞭毛藻), components of phytoplankton
– Diatoms (矽藻), which have glassy walls
Figure 15.22a, b
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– Green algae, unicellular and colonial
Figure 15.22c, d
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Seaweeds
• Seaweeds
– Are large, multicellular marine algae
– Grow on rocky shores and just offshore
– Are often edible
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• The three major groups of seaweeds
(b) Red algae
(a) Green algae
(c) Brown algae
Figure 15.23
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EVOLUTION CONNECTION:
THE ORIGIN OF MULTICELLULAR LIFE
• Multicellular organisms
– Are different from unicellular ones
– Have specialized cells
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Unicellular protist
• The evolutionary
links between
unicellular and
multicellular
organisms were
probably colonial
protists
1
Colony
2
Locomotor cells
Foodsynthesizing
cells
Early multicellular
organism with
specialized,
interdependent
cells
Figure 15.24
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3
Gamete
Somatic
cells
Later organism with
gametes and somatic
(non-reproductive) cells
SUMMARY OF KEY CONCEPTS
• Major Episodes in the History of Life
Millions of years ago
475
570
1,000
1,700
2,500
3,500
4,500
Major Episode
Plants and fungi colonize land
All major animal phyla established
First multicellular organisms
Oldest eukaryotic fossils
Accumulation of atmospheric 02
Oldest prokaryotic fossils
Origin of Earth
Visual Summary 15.1
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• A Four-Stage
Hypothesis for
the Origin of Life
Inorganic compounds
1
Abiotic synthesis
Organic monomers
2 Polymerization
Polymer
3 Self-replication
Complementary chain
4 Packaging
Membrane-enclosed compartment
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Visual Summary 15.2
• The Two Main Branches of Prokaryotic
Evolution: Bacteria and Archaea
Prokaryotes
Domain Bacteria
Domain Archaea
(e.g., extremophiles)
Visual Summary 15.3
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• The Nutritional Diversity of Prokaryotes
Nutritional Mode
Energy Source
Photoautotroph
Sunlight
Carbon Source
CO
Chemoautotroph
Inorganic chemicals
Photoheterotroph
Sunlight
2
Organic compounds
Chemoheterotroph
Organic compounds
Visual Summary 15.4
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