Transcript ch. 17 history of life

CH. 17 HISTORY OF LIFE
17-2 Formation
a Fossil about
The FOSSILFigure
RECORD
providesofevidence
the history
of life on Earth (and for evolution).
Section
17-1
Alone, it does not PROVE evolution. Why?
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.
RELATIVE DATING
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
Pompeii
Compare/Contrast Table
Section 17-1
Comparing Relative and Absolute Dating of Fossils
Can determine
Is performed by
Drawbacks
Relative Dating
Absolute Dating
Age of fossil with respect to
another rock or fossil (that is,
older or younger)
Age of a fossil in years
Comparing depth of a fossil’s
source stratum to the position
of a reference fossil or rock
Determining the relative
amounts of a radioactive
isotope and nonradioactive
isotope in a specimen
Imprecision and limitations of
age data
Difficulty of radioassay
laboratory methods
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?
Concept Map
EARTH’S EARLY HISTORY
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.
Earth’s early atmosphere probably contained hydrogen
cyanide, carbon dioxide, carbon monoxide, nitrogen,
hydrogen sulfide, and water. Hot and no good for life!
Figure 17-8 Miller-Urey Experiment
THE FIRST ORGANIC MOLECULES
Section 17-2
•
•
•
•
MILLER & UREY
FILLED A FLASK WITH
HYDROGEN, METHANE,
AMMONIA, AND WATER TO
REPRESENT EARTH’S 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
Water
vapor
Cold
water
cools
chamber,
causing
droplets
to form
Liquid containing
amino acids and
other organic
compounds
PHOTOSYNTHETIC BACTERIA ADDED OXYGEN TO EARTH’S
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???
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???
ORIGIN OF EUKARYOTIC
CELLS: ENDOSYMBIOTIC
Figure 17-12 Endosymbiotic
Theory
THEORY (EUK CELLS AROSE FROM LIVING
Section 17-2
COMMUNITIES FORMED BY PROKARYOTIC
ORGANISMS)
Chloroplast
Aerobic
bacteria
Ancient Prokaryotes
Nuclear
envelope
evolving
Plants and
plantlike
protists
Photosynthetic
bacteria
Mitochondrion
Primitive Photosynthetic
Eukaryote
Ancient Anaerobic
Prokaryote
Primitive Aerobic
Eukaryote
Animals, fungi, and
non-plantlike protists
Flowchart
CH. 18 TAXONOMY
Section 18-1
Linnaeus’s System of Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
BINOMIAL NOMENCLATURE: (SCIENTIFIC NAME) TWO-PART
Figure 18-5 Classification of Ursus arctos
NAME (GENUS & SPECIES). ALWAYS WRITTEN IN ITALICS,
GENUS CAPITALIZED, SPECIES LOWERCASED
Section 18-1
Grizzly bear Black bear
Giant
panda
Red fox
Coral Sea star
Abert
squirrel snake
KINGDOM Animalia
PHYLUM Chordata
CLASS Mammalia
ORDER Carnivora
FAMILY Ursidae
GENUS Ursus
SPECIES Ursus arctos
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, welldeveloped cerebrum)
Scientific Name: Homo sapiens
Traditional Classification Versus Cladogram
TRADITIONAL CLASSIFICATION VS
Section 18-2
CLADOGRAM (PHYLOGENETIC TREE)
Appendages
Crab
Conical Shells
Barnacle
Limpet
Crustaceans
Crab
Gastropod
Barnacle
Limpet
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
CLASSIFICATION
BASED ON VISIBLE
SIMILARITIES
CLADOGRAM
Traditional Classification Versus Cladogram
TRADITIONAL CLASSIFICATION VS
Section 18-2
CLADOGRAM (PHYLOGENETIC TREE)
Appendages
Crab
Conical Shells
Barnacle
Limpet
Crustaceans
Crab
Gastropod
Barnacle
Limpet
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
CLASSIFICATION
BASED ON VISIBLE
SIMILARITIES
CLADOGRAM
Concept Map
Section 18-3
Living
Things
are characterized by
Eukaryotic
cells
and differing
Important
characteristics
which place them in
Cell wall
structures
such as
Domain
Eukarya
Prokaryotic cells
which is subdivided into
which place them in
Domain
Bacteria
Domain
Archaea
which coincides with
which coincides with
Kingdom
Eubacteria
Kingdom
Archaebacteria
Kingdom
Plantae
Kingdom
Fungi
Kingdom
Protista
Kingdom
Animalia
Figure 18-12 Key Characteristics of
Kingdoms and Domains
CHARACTERISTICS OF
KINGDOMS AND DOMAINS
Section 18-3
Classification of Living Things
DOMAIN
Bacteria
Archaea
KINGDOM
Eubacteria
Archaebacteria
CELL TYPE
Eukarya
Protista
Fungi
Plantae
Animalia
Prokaryote
Prokaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Cell walls with
peptidoglycan
Cell walls
without
peptidoglycan
Cell walls of
cellulose in
some; some
have
chloroplasts
Cell walls of
chitin
Cell walls of
cellulose;
chloroplasts
No cell walls
or chloroplasts
Unicellular
Unicellular
Most unicellular;
some colonial;
some
multicellular
Most
multicellular;
some
unicellular
Multicellular
Multicellular
MODE OF
NUTRITION
Autotroph or
heterotroph
Autotroph or
heterotroph
Autotroph or
heterotroph
Heterotroph
Autotroph
Heterotroph
EXAMPLES
Streptococcus,
Escherichia coli
Methanogens,
halophiles
Amoeba,
Paramecium,
slime molds,
giant kelp
Mushrooms,
yeasts
Mosses, ferns,
flowering
plants
Sponges,
worms,
insects, fishes,
mammals
CELL
STRUCTURES
NUMBER OF
CELLS
CLADOGRAM
CLADOGRAM & PHYLOGENETIC
TREE (TYPE OF CLADOGRAM)
GEL ELECTROPHORESIS AND
CLADISTICS
DESIGN A CLADOGRAM THAT ILLUSTRATES THE
EVOLUTIONARY RELATIONSHIPS SHOWN BY THIS
GEL.
Figure 18-13 Cladogram of Six Kingdoms
and Three Domains
CLADOGRAM OF 6 KINGDOMS
AND 3 DOMAINS
Section 18-3
DOMAIN
ARCHAEA
DOMAIN
EUKARYA
Kingdoms
DOMAIN
BACTERIA
Eubacteria
Archaebacteria
Protista
Plantae
Fungi
Animalia
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.[4][5]