Transcript B. Fossil record

Chapter 17
History of Life
17-1
I. The Fossil Record
scientists who collect and
A. Paleontologists- study fossils
B. Fossil record1. Info. from past; about structure of organisms, what
they ate, what ate them (predator), in what
environment they lived, and the order in which they
lived.
2. Provides evidence about the history of life on Earth.
3. Shows how different groups of organisms, including
species, have changed over time.
4. Is incomplete, so provides limited info. about
history of life on Earth
5. Over 99% of all species that lived on Earth have
died out.
6. Most fossils form in sedimentary rock.
a. Sedimentary rock forms when particles of
sand, silt, and clay are compressed together
b. Fossil Formation: Conditions must be
conducive to fossils forming.
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II. Methods of Dating Fossils
A. Relative dating1. the age determined by comparing placement of
fossils in other layers of rock
2. Rock layers form in order by age—the oldest on
the bottom, with more recent layers on top.
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3. Index fossil - a species that is recognizable and that
existed for a short period but had a wide geographic
range
a. Used to compare the relative ages of fossils
B. Absolute Dating
1. Radioactive dating is the use of half-lives to
determine the age of a sample.
a. half-life = length of time required for half of the
radioactive atoms in a sample to decay.
b. Calculated by the age of a sample based on the
amount of remaining radioactive isotopes it contains.
Page 420
2. Carbon-14 Dating = most common forms of fossil
dating.
a. begins to decay when an organism dies.
b. Carbon-12 is not radioactive and does not decay
c. By comparing the amounts of carbon-14 and carbon12 in a fossil, researchers can determine when the
organism lived.
III. Geologic Time Scale
A. Paleontologists use the geologic time scale to
represent evolutionary time.
B. Basic divisions are eras and periods.
C. Eras are subdivided into periods
D. Geologists divide the time between Precambrian
time and the present into three eras:
–Paleozoic Era
–Mesozoic Era
–Cenozoic Era
Clock Model of
Earth’s History
Page 422
First humans
Radiation of mammals
First land plants
First
prokaryotes
First multicellular organisms
Cenozoic Era
Mesozoic Era
Paleozoic Era
Precambrian Time
First
eukaryotes
Accumulation of
atmospheric
oxygen
17-2
IV. Formation of Early Earth
A. 4 billion years ago, Earth cooled and solid rocks formed
on its surface.
B. Millions of years later, volcanic activity shook Earth’s
crust.
C. 3.8 billion years ago, Earth’s surface cooled for water to
remain a liquid  oceans covered much of the surface.
D. Earth's early atmosphere -NO free OXYGEN- may
have had hydrogen cyanide, carbon dioxide, carbon
monoxide, nitrogen, hydrogen sulfide, and water.
ADD TO NOTES:
1. 1950’s- Miller and
Urey tried to simulate
atmosphere on early
Earth in a lab setting.
Mixture of gases simulating
atmosphere of early Earth
2. Experimentsuggested that organic
compounds needed for
life could have arisen
from simpler inorganic
compounds present on
early Earth.
Result: Liquid -amino acids and
other organic compounds produced
Spark
simulating
lightning
storms
Condensation
chamber
Water vapor
Cold water cools
chamber, causing
droplets to form.
Add to notes: Honors ONLY
3. From simple, organic molecules to cells? How?
a. Proteinoid Microspheres- structurally like cells, but
missing genetic material to pass on traits
Like cells: they have selectively permeable membrane;
simple ways of storing and releasing energy; globular
in shape; BUT MISSING GENETIC MATERIAL
b. RNA may have been the first genetic material
eventually leading to DNA as genetic material
V. The First Cells?
A. Evidence suggests - cells similar to modern bacteria
were common 200-300 mill. years after Earth had water .
VI. Microfossils (microscopic fossils)
A. unicellular prokaryotic organisms resembled
modern bacteria.
B. have been found in rocks over 3.5 billion years old
C. must have evolved without oxygen if primitive Earth
had no free oxygen.
D. About 2.2 bya, photosynthetic bacteria began to
release oxygen into the oceans, then the atmosphere.
VII. Significance of Oxygen on Earth
A. Oxygen (photosynthesis) in the atmosphere
meant life forms could grow larger and even
become multicellular.
VIII. Origin of Eukaryotic Cells
A. Endosymbiotic Theory  eukaryotic cells
with organelles arose from living communities
of prokaryotic organisms.
•Endosymbiotic Theory
Page 427
Plants and
plantlike
protists
Primitive Photosynthetic
Eukaryote
Ancient Anaerobic
Prokaryote
Primitive Aerobic
Eukaryote
Animals,
fungi, and
non-plantlike
protists
ADD TO NOTES: Theory of Endosymbiosis
1. Proposed that chloroplasts and mitochondria arose
from invading prokaryotes that enter larger cells.
2. Would than be able to use oxygen for ATP  mitochondria
Mitochondrion
Ancient Anaerobic Prokaryote
Primitive Aerobic Eukaryote
Endosymbiotic Theory
Prokaryotes that carried out
photosynthesis evolved into
chloroplasts.
Chloroplast
Photosynthetic
bacteria
Primitive Photosynthetic Eukaryote
IX. Asexual Reproduction
A. Prokaryotes reproduce asexually by binary fission.
B. Results of asexual reproduction:
1. Daughter cells are exact copies of the parent cell.
2. Restricts genetic variation to mutations in DNA.
X. Sexual Reproduction and Multicellularity
1. Shuffles genes in each generation
2. Sexual reproduction results in:
a. offspring that are never identical to the parents
ADD: b. more “options” to increase chances of
survival
17-4
XI. Patterns of Evolution
A. Macroevolution1. refers to large-scale
evolutionary patterns and
processes
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B. Six Patterns of Macroevolution
1. extinction
a. Disappearance of an entire species
2. adaptive radiation- form of divergent evolutionhomologous structures
a. process by which a single species or a small
group of species evolves into several different
forms that live in different ways
b. Darwin's finches, more than a dozen species
evolved from a single species
c. The disappearance of dinosaurs resulted in
the adaptive radiation of mammals
Adaptive Radiation in Mammals
Artiodactyls Cetaceans
Tubulidentates
Perissodactyls
Sirenians
Hyracoids
Proboscideans
Ancestral Mammals
This diagram shows part of the adaptive radiation of mammals, emphasizing current hypotheses about how a group of
ancestral mammals diversified over millions of years into several related living orders. Note that the dotted lines and question
marks in this diagram indicate a combination of gaps in the fossil record and uncertainties about the timing of evolutionary
branching.
3. convergent evolution- evidence = analogous structures
a. process by which unrelated organisms come to
resemble one another is called convergent evolution
b. resulted in sharks, fish, dolphins, whales, seals,
and penguins
c. Convergent Evolution Involves Analogous Structures
4. coevolution
a. process by which 2 species evolve in response to
changes in each other over time
5. Gradualism vs. Punctuated Equilibrium
a. Darwin felt that biological change Gradualism
was slow and steady with small
changes over time = gradualism
b. Punctuated equilibrium- pattern of
evolution in which long stable periods
are interrupted by rapid change
Punctuated equilibrium
6. changes in developmental genes and body plans
a. Changes in genes for growth and differentiation
(hox genes) during embryological development
could produce changes in body shape and size
b. Changes in expression of dev. Genes (hox genes)
may explain how wing differences evolved.
17-1
– Which of the following statements about fossils
is NOT true?
A. Most fossils form in sedimentary rock.
B. Fossils occur in a particular order.
C. Only a small portion of fossils are from extinct
organisms.
D. Fossils can be used in relative dating of rock
formations.
17-1
– The fossil record consistently shows evidence
that
A. all forms of life have existed in all geologic
eras.
B. living organisms have only been on Earth
for a short time.
C. living things have changed over time.
D. ancient life-forms are much the same as
forms found living today.
17-1
– Index fossils assist paleontologists in dating rocks
because they represent species that
A. were widely distributed and existed for a very
long time.
B. existed in a single location for a short period
of time.
C. were widely distributed and existed for a short
time.
D. existed in a single location for a very long
time.
17-1
– Determining the age of a fossil by
comparing its placement with fossils in
other layers of rock is called
A. carbon-14 dating.
B. fossil-indexing.
C. relative dating.
D. absolute dating.
17-1
– According to the geologic time scale,
geologic time begins with
A. Precambrian Time.
B. the Paleozoic Era.
C. the Quaternary Period.
D. the Cambrian Era.
17-2
– Which of the following gases was
probably NOT present in the early
Earth’s atmosphere?
A. hydrogen cyanide
B. oxygen
C. nitrogen
D. carbon monoxide
17-2
– Miller and Urey's experiment was a
simulation of Earth's early
A. volcanic activity.
B. formation.
C. atmosphere.
D. life.
17-2
– Proteinoid microspheres are different from cells
because microspheres
A. have selectively permeable membranes.
B. do not have DNA or RNA.
C. have a simple means of storing and
releasing energy.
D. separate their internal environment from
the external environment.
17-2
– The hypothesis that RNA sequences appeared
before DNA sequences
A. has some evidence in its favor but is still
being tested.
B. has been rejected since DNA is required to
make RNA.
C. has been proven since RNA has been made
in laboratories.
D. has been rejected because it is illogical.
17-2
– As concentrations of oxygen rose in the
ancient atmosphere of Earth, organisms
began to evolve
A. anaerobic pathways.
B. plasma membranes.
C. metabolic pathways that used
oxygen.
D. photosynthesis.
17-4
– Darwin's species of finches were very
similar but different in beak size and
feeding habits. This is an example of
A. convergent evolution.
B. coevolution.
C. adaptive radiation.
D. stabilizing selection.
17-4
– A slow steady change in a particular
line of descent is called
A. coevolution.
B. gradualism.
C. punctuated equilibrium.
D. convergent evolution.
17-4
– Master control genes are called
A. hox genes.
B. developmental genes.
C. embryonic genes.
D. regulatory genes.
17-4
– Some evidence suggests that species do not
change much over long periods of time and
then undergo relatively short periods of rapid
speciation. This kind of change is called
A. coevolution.
B. genetic equilibrium.
C. adaptive radiation.
D. punctuated equilibrium.
17-4
– Fossil evidence shows that mass extinctions
A. ended the existence of many species in a short
period of time.
B. occurred mainly when the dinosaurs disappeared.
C. require an asteroid strike to occur.
D. caused convergent evolution among animals.
17-1
– Which of the following statements about fossils
is NOT true?
A. Most fossils form in sedimentary rock.
B. Fossils occur in a particular order.
C. Only a small portion of fossils are from extinct
organisms.
D. Fossils can be used in relative dating of rock
formations.
17-1
– The fossil record consistently shows evidence
that
A. all forms of life have existed in all geologic
eras.
B. living organisms have only been on Earth
for a short time.
C. living things have changed over time.
D. ancient life-forms are much the same as
forms found living today.
17-1
– Index fossils assist paleontologists in dating rocks
because they represent species that
A. were widely distributed and existed for a very
long time.
B. existed in a single location for a short period
of time.
C. were widely distributed and existed for a short
time.
D. existed in a single location for a very long
time.
17-1
– Determining the age of a fossil by
comparing its placement with fossils in
other layers of rock is called
A. carbon-14 dating.
B. fossil-indexing.
C. relative dating.
D. absolute dating.
17-1
– According to the geologic time scale,
geologic time begins with
A. Precambrian Time.
B. the Paleozoic Era.
C. the Quaternary Period.
D. the Cambrian Era.
17-2
– Which of the following gases was
probably NOT present in the early
Earth’s atmosphere?
A. hydrogen cyanide
B. oxygen
C. nitrogen
D. carbon monoxide
17-2
– Miller and Urey's experiment was a
simulation of Earth's early
A. volcanic activity.
B. formation.
C. atmosphere.
D. life.
17-2
– Proteinoid microspheres are different from cells
because microspheres
A. have selectively permeable membranes.
B. do not have DNA or RNA.
C. have a simple means of storing and
releasing energy.
D. separate their internal environment from
the external environment.
17-2
– The hypothesis that RNA sequences appeared
before DNA sequences
A. has some evidence in its favor but is still
being tested.
B. has been rejected since DNA is required to
make RNA.
C. has been proven since RNA has been made
in laboratories.
D. has been rejected because it is illogical.
17-2
– As concentrations of oxygen rose in the
ancient atmosphere of Earth, organisms
began to evolve
A. anaerobic pathways.
B. plasma membranes.
C. metabolic pathways that used
oxygen.
D. photosynthesis.
17-4
– Darwin's species of finches were very
similar but different in beak size and
feeding habits. This is an example of
A. convergent evolution.
B. coevolution.
C. adaptive radiation.
D. stabilizing selection.
17-4
– A slow steady change in a particular
line of descent is called
A. coevolution.
B. gradualism.
C. punctuated equilibrium.
D. convergent evolution.
17-4
– Master control genes are called
A. hox genes.
B. developmental genes.
C. embryonic genes.
D. regulatory genes.
17-4
– Some evidence suggests that species do not
change much over long periods of time and
then undergo relatively short periods of rapid
speciation. This kind of change is called
A. coevolution.
B. genetic equilibrium.
C. adaptive radiation.
D. punctuated equilibrium.
17-4
– Fossil evidence shows that mass extinctions
A. ended the existence of many species in a short
period of time.
B. occurred mainly when the dinosaurs disappeared.
C. require an asteroid strike to occur.
D. caused convergent evolution among animals.