Transcript The History of Life

Chapter 14 The History of Life
Section 1: Fossil Evidence of Change
Section 2: The Origin of Life
Main Idea: Fossils provide evidence of
the change in organisms.
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1. fossil-any preserved evidence of an
organism
2. sedimentary rock- all fossils are formed in
this type of rock
3. paleontologist – scientist who studies fossils
4. relative dating – method used to determine
the age of a rock by comparing it to other rocks
in the surrounding layers
5. geological time scale- model that expresses
the major geological and biological events in
Earth’s history
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6. Plate tectonics- describes the
movements of several large
plates that make up the surface
of the Earth.
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Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Clues in Rocks
1. A fossil is any preserved evidence of an
organism.
2. The fossil record is like a book with many
missing pages. Perhaps more than 99
percent of the species that have ever lived
are now extinct, but only a tiny percentage of
these organisms are preserved as fossils.
3. Most organisms decompose before they
have a chance to become fossilized.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
4. Only those organisms buried rapidly in
sediment are readily preserved.
5. This occurs more frequently with organisms
living in water because the sediment in aquatic
environments is constantly settling, covering,
and preserving remains of organisms.
6. Nearly all fossils are formed in sedimentary rock.
7. Sedimentary rock is formed from
accumulated sediments settling over time.
These sediments eventually harden and form
rock.
8. Fossils formed by:
• Organism dies and is buried in sediment
• Minerals may replace the organic matter or
fill the empty pore spaces of the organism.
• In other cases, the organism decays,
leaving behind an impression of his body.
• Sediments eventually harden into rock.
The Fossilization Process
• Sediments from upstream
rapidly cover the body, slowing
its decomposition. Minerals
from the sediments seep into the
body.
• Over time, additional layers
of sediment compress the
sediments around the body,
forming rock. Minerals
eventually replace all the body’s
bone material.
• A Protoceratops
drinking at a river falls
into the water and
drowns (dies).
• Earth
movements or
erosion may
expose the fossil
millions of years
after it formed.
Chapter 14
The History of Life
Fossil Formation
9. A paleontologist is a scientist who
studies fossils. From fossil evidence,
paleontologists infer the diet of an
organism and the environment in which it
lived.
10. To determine the age of a fossil,
scientist’s use two methods relative dating
and radiometric dating.
11. Relative dating is a method used to
determine the age of rocks by comparing
them with those in other layers.
12. Relative dating is
based on the law of
superposition, which
states that younger
layers of rock are
deposited on top of
older layers.
13. Radiometric
dating uses the decay
of radioactive
isotopes to measure
the age of the rock.
14. The geologic
time scale is a model
that expresses the
major geological and
biological events in
Earth’s history. It is
made of epochs, eras
and periods.
The geologic
time scale
• The divisions in the
geologic time scale
are distinguished
by the organisms
that lived during
that time interval.
15. Geology is the scientific study of the
origin, history, and structure of the earth
Theory of continental drift - the world was
made up of a single continent through most of
geologic and eventually separated and drifted
apart, forming into the seven continents we
have today.
16. Plate tectonics
describes the
movement of several
large plates that
make up the surface
of Earth.
Chapter 14
The History of Life
17. Early ideas on the origin of life–
spontaneous generation is the idea that life
arises from nonlife.
Theory of biogenesis- only living organisms
can produce other living organisms.
18. Modern ideas of
the origin of life—
primordial soup theory in
1920’s proposed that the
early atmosphere of
earth had a mix of gases
and organic molecules
with energy from the sun
or lightning could have
started life.
19. Some scientists
theorized that life
could have come
from organic
reactions in deep sea
vents in the ocean.
20. Cellular
evolution—first cells
were prokaryotes.
Scientists believe that
photosynthetic
prokaryotes like
cyanobacteria
evolved from the first
bacteria.
21. Eukaryotic cells appeared in fossil record
much later. Scientist use the endosymbiont
theory to explain how more complex cells
developed.
This theory states
that the mitochondria
and chloroplasts of a
eukaryotic cell were
once bacteria that
entered another
bacteria as either
food or a parasite.
Chapter 14
The History of Life
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Chapter 14
The History of Life
14.1 Formative
Questions
In which type of rock do paleontologists search
for fossils?
A. igneous
B. metamorphic
C. sedimentary
D. volcanic
Chapter 14
The History of Life
14.1 Formative
Questions
Which dating method determines the age of
rocks by comparing them to rocks in other
layers?
A. absolute dating
B. geological dating
C. relative dating
D. sedimentary dating
Chapter 14
The History of Life
Glencoe Biology Transparencies
Chapter 14
The History of Life
Image Bank
Chapter 14
The History of Life
Vocabulary
Section 1
fossil
era
paleontologist
period
relative dating
Cambrian explosion
law of superposition
K-T boundary
radiometric dating
plate tectonics
half-life
geologic time scale
Chapter 14
The History of Life
Vocabulary
Section 2
spontaneous generation
theory of biogenesis
endosymbiont theory
Chapter 14
The History of Life
Animation
 Visualizing Geologic Time
 Continental Drift
 Miller-Urey Experiment