CH. 17 HISTORY OF LIFE

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CH. 17 HISTORY OF LIFE
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The FOSSIL RECORD provides evidence about the
history of life on Earth (and for evolution).
Alone, it does not PROVE evolution. Why?
Figure 17-2 Formation of a Fossil
Section 17-1
Water carries small rock particles to lakes and
seas.
Dead organisms are buried by layers of sediment,
which forms new rock.
The preserved remains may later be discovered and
studied.
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RELATIVE DATING
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HOW FOSSILS FORM

• REQUIRES PRECISE CONDITIONS!
• EGGS, FOOTPRINTS, LEAVES, SHELLS, BONES, ANIMAL
  DROPPINGS, WOOD..
• MOST FORM IN SEDIMENTARY ROCK
• SOMETIMES SMALL PARTICLES ENCASE REMAINS
  PRESERVE ONLY IMPRINT
• SOMETIMES HARD PARTS PRESERVED WHEN THEY ARE
  REPLACED BY LONG-LASTING MINERAL COMPOUNDS
• SOMETIMES PERFECTLY PRESERVED WHEN BURIED QUICKLY
  BY FINE-GRAINED CLAY OR VOLCANIC ASH BEFORE THEY
  BEGIN TO DECAY

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Pompeii
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Compare/Contrast Table
Section 17-1
Comparing Relative and Absolute Dating of Fossils
Relative Dating
Absolute Dating
Can determine Is performed by Drawbacks
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ABSOLUTE DATING (RADIOACTIVE)

• IN RADIOACTIVE DATING (THINK CARBON-14),
  SCIENTISTS CALCULATE THE AGE OF A SAMPLE BASED ON
  THE AMOUNT OF REMAINING RADIOACTIVE ISOTOPES IT
  CONTAINS.
• HALF-LIFE THE AMOUNT OF TIME REQUIRED FOR HALF
  OF THE RADIOACTIVE ATOMS IN A SAMPLE TO DECAY.

• Practice
• The half-life of carbon-14 is 5730 years. What
  is the age of a fossil containing 1/16 the amount
  of carbon-14 of living organisms?

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EARTHS EARLY HISTORY
Concept Map
Section 17-2
Evolution of Life
Early Earth was hot atmosphere contained
poisonous gases.
Earth cooled and oceans condensed.
Simple organic molecules may have formed in the
oceans..
Small sequences of RNA may have formed and
replicated.
First prokaryotes may have formed when RNA or DNA
was enclosed in microspheres.
Later prokaryotes were photosynthetic and
produced oxygen.
An oxygenated atmosphere capped by the ozone
layer protected Earth.
First eukaryotes may have been communities of
prokaryotes.
Multicellular eukaryotes evolved.
Sexual reproduction increased genetic
variability, hastening evolution.
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Earths early atmosphere probably contained
hydrogen cyanide, carbon dioxide, carbon
monoxide, nitrogen, hydrogen sulfide, and water.
Hot and no good for life!
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THE FIRST ORGANIC MOLECULES
Figure 17-8 Miller-Urey Experiment
Section 17-2

• MILLER UREY
• FILLED A FLASK WITH HYDROGEN, METHANE, AMMONIA,
  AND WATER TO REPRESENT EARTHS EARLY ATMOSPHERE.
• PASSED ELECTRIC SPARKS THROUGH THE MIXTURE.
• RESULT SEVERAL AMINO ACIDS BEGAN TO ACCUMULATE.
• SUGGESTED HOW MIXTURES OF THE ORGANIC COMPOUNDS
  NECESSARY FOR LIFE COULD HAVE ARISEN FROM SIMPLER
  COMPOUNDS PRESENT ON A PRIMITIVE EARTH!

Mixture of gases simulating atmospheres of early
Earth
Spark simulating lightning storms
Condensation chamber
Cold water cools chamber, causing droplets to form
Water vapor
Liquid containing amino acids and other organic
compounds
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PHOTOSYNTHETIC BACTERIA ADDED OXYGEN TO EARTHS
ATMOSPHERE. RUST ON OCEAN FLOOR, OCEANS TURNED
BLUE-GREEN, OXYGEN ACCUMULATED IN THE ATMOSPHERE,
METHANE AND HYDROGEN SULFIDE DECREASED, AND THE
OZONE LAYER FORMED. OXYGEN FOR???
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THE FIRST CELL???

• DROPLETS
• COACERVATES tiny spherical droplets of assorted
  organic molecules (specifically, lipid molecules)
  which are held together by hydrophobic forces
  from a surrounding liquid. form spontaneously
  in dilute organic solutions
• MICROSPHERES protocells like coacervates
• BUBBLES???

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ORIGIN OF EUKARYOTIC CELLS ENDOSYMBIOTIC THEORY
(EUK CELLS AROSE FROM LIVING COMMUNITIES FORMED
BY PROKARYOTIC ORGANISMS)
Figure 17-12 Endosymbiotic Theory
Section 17-2
Chloroplast
Plants and plantlike protists
Aerobic bacteria
Ancient Prokaryotes
Photosynthetic bacteria
Nuclear envelope evolving
Mitochondrion
Primitive Photosynthetic Eukaryote
Animals, fungi, and non-plantlike protists
Primitive Aerobic Eukaryote
Ancient Anaerobic Prokaryote
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CH. 18 TAXONOMY
Flowchart
Section 18-1
Linnaeuss System of Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
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BINOMIAL NOMENCLATURE (SCIENTIFIC NAME) TWO-PART
NAME (GENUS SPECIES). ALWAYS WRITTEN IN
ITALICS, GENUS CAPITALIZED, SPECIES LOWERCASED
Figure 18-5 Classification of Ursus arctos
Section 18-1
Coral snake
Abert squirrel
Sea star
Grizzly bear
Black bear
Giant panda
Red fox
KINGDOM Animalia
PHYLUM Chordata
CLASS Mammalia
ORDER Carnivora
FAMILY Ursidae
GENUS Ursus
SPECIES Ursus arctos
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CLASSIFICATION OF MAN

• Kingdom Animalia
• Phylum Chordata (notochords)
• Class Mammalia(hair, milk glands, diaphragm)
• Order Primate (fingers, flat nails)
• Family Hominidae (upright posture, flat face)
• Genus Homo (double-curved spine, long youth,
  life span)
• Species Sapiens (chin, high forehead,
  well-developed cerebrum)
• Scientific Name Homo sapiens

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TRADITIONAL CLASSIFICATION VS CLADOGRAM
(PHYLOGENETIC TREE)
Traditional Classification Versus Cladogram
Section 18-2
Appendages
Conical Shells
Crustaceans
Gastropod
Crab
Crab
Limpet
Limpet
Barnacle
Barnacle
Molted exoskeleton
Segmentation
Tiny free-swimming larva
CLADOGRAM
CLASSIFICATION BASED ON VISIBLE SIMILARITIES
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TRADITIONAL CLASSIFICATION VS CLADOGRAM
(PHYLOGENETIC TREE)
Traditional Classification Versus Cladogram
Section 18-2
Appendages
Conical Shells
Crustaceans
Gastropod
Crab
Crab
Limpet
Limpet
Barnacle
Barnacle
Molted exoskeleton
Segmentation
Tiny free-swimming larva
CLASSIFICATION BASED ON VISIBLE SIMILARITIES
CLADOGRAM
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Concept Map
Section 18-3
Living Things
are characterized by
Important characteristics
which place them in
and differing
Domain Eukarya
Cell wall structures
such as
which is subdivided into
which place them in
which coincides with
which coincides with
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CHARACTERISTICS OF KINGDOMS AND DOMAINS
Figure 18-12 Key Characteristics of Kingdoms and
Domains
Section 18-3
Classification of Living Things
DOMAIN KINGDOM CELL TYPE CELL
STRUCTURES NUMBER OF CELLS MODE OF
NUTRITION EXAMPLES
Bacteria Eubacteria Prokaryote Cell walls with
peptidoglycan Unicellular Autotroph or
heterotroph Streptococcus, Escherichia coli
Archaea Archaebacteria Prokaryote Cell walls
without peptidoglycan Unicellular Autotroph
or heterotroph Methanogens, halophiles
Protista Eukaryote Cell walls of cellulose in
some some have chloroplasts Most unicellular
some colonial some multicellular Autotroph or
heterotroph Amoeba, Paramecium, slime molds,
giant kelp
Fungi Eukaryote Cell walls of
chitin Most multicellular some
unicellular Heterotroph Mushrooms, yeasts
Plantae Eukaryote Cell walls of cellulose
chloroplasts Multicellular Autotroph Mos
ses, ferns, flowering plants
Animalia Eukaryote No cell walls or
chloroplasts Multicellular Heterotroph
Sponges, worms, insects, fishes, mammals
Eukarya
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CLADOGRAM
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CLADOGRAM PHYLOGENETIC TREE (TYPE OF CLADOGRAM)
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GEL ELECTROPHORESIS AND CLADISTICS

• DESIGN A CLADOGRAM THAT ILLUSTRATES THE
  EVOLUTIONARY RELATIONSHIPS SHOWN BY THIS GEL.

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CLADOGRAM OF 6 KINGDOMS AND 3 DOMAINS
Figure 18-13 Cladogram of Six Kingdoms and Three
Domains
Section 18-3
DOMAIN ARCHAEA
DOMAIN EUKARYA
Kingdoms
Eubacteria Archaebacteria Protista Plantae Fungi A
nimalia
DOMAIN BACTERIA
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MOLECULAR CLOCK

• USES DNA COMPARISONS TO ESTIMATE THE LENGTH OF
  TIME THAT TWO SPECIES HAVE BEEN EVOLVING
  INDEPENDENTLY.

The genetic equidistance phenomenon was first
noted in 1963 by E. Margoliash, who wrote "It
appears that the number of residue differences
between cytochrome C of any two species is mostly
conditioned by the time elapsed since the lines
of evolution leading to these two species
originally diverged. If this is correct, the
cytochrome c of all mammals should be equally
different from the cytochrome c of all birds.
Since fish diverges from the main stem of
vertebrate evolution earlier than either birds or
mammals, the cytochrome c of both mammals and
birds should be equally different from the
cytochrome c of fish. Similarly, all vertebrate
cytochrome c should be equally different from the
yeast protein."2 For example, the difference
between the cytochrome C of a carp and a frog,
turtle, chicken, rabbit, and horse is a very
constant 13 to 14. Similarly, the difference
between the cytochrome C of a bacterium and
yeast, wheat, moth, tuna, pigeon, and horse
ranges from 64 to 69. Together with the work of
Emile Zuckerkandl and Linus Pauling, the genetic
equidistance result directly led to the formal
postulation of the molecular clock hypothesis in
the early 1960s.3 Genetic equidistance has
often been used to infer equal time of separation
of different sister species from an
outgroup.45