1. Chapter 19: The History of
Life
2. 19.1 The Fossil Record
3. Fossils and Ancient Life
Extinct
5. Species that has died out.
4. Types of Fossils
5. Footprints, burrows, tracks, teeth, pieces of bone, in all
shapes and sizes.
4. Fossils in Sedimentary Rock
5. Over many years, water pressure gradually compresses
the lower layers and turns the sediments into rock.
4. What Fossils Can Reveal
Paleontologists
5. Researchers who study fossils.
5. Fossils can reconstruct entire ancient ecosystems.
3. Dating Earth’s History
4. Relative Dating
Relative Dating
Index Fossils
5. Places rock layers and their fossils into a temporal
sequence.
5. Distinctive fossils used to establish and compare the
relative ages of rock layers and the fossils they contain.
4. Radiometric Dating
Radiometric Dating
Half-Life
5. Relies on radioactive isotopes, which decay, or break
down, into nonradioactive isotopes at a steady rate.
5. Half of the original radioactive atoms have decayed.
3. Geologic Time Scale
Geologic Time Scale
5. Timeline of Earth’s history.
4. Establishing the Time Scale
5. Paleontologists discovered major changes in the fossil
record at boundaries between certain rock layers.
4. Divisions of the Geologic Time Scale
5. Cretaceous Period was 80 million years long
5. Hadean Eon = 4.6 billion years ago
5. Archean Eon = 4 billion
5. Proterozoic Eon = 2.5 billion
5. Phanerozoic Eon from end of Proterozoic to present day
5. Eons are divided into eras.
Era
Period
5. A long and distinct period of history with a particular
feature or characteristic.
5. A portion of time that ranges from nearly 100 millions
of years to just under 2 million years.
4. Naming the Divisions
5. Precambrian time covers about 90 percent of Earth’s
history.
3. Life on a Changing Planet
4. Physical Forces
Plate Tectonics
5. Climate is one of the most important aspects of Earth’s
physical environment.
5. Explains how solid “plates” move slowly above the
Earth’s molten core- a process called continental drift.
5. Continental drift affects climate.
4. Biological Forces
SUMMARY
5. Organisms today shape the landscape by building soil
from rock, and sand and cycle nutrients through the
biosphere.
Paleontologists study the Earth, and they have a geologic
time scale. Eons are separated into eras, and eras are
separated into periods.
2. 19.2 Patterns and Processes
of Evolution
3. Speciation and Extinction
Macroevolutionary Patterns
5. Grand transformations in anatomy, phylogeny, ecology,
and behavior
4. Macroevolution and Cladistics
5. Paleontologists study fossils to learn about patterns of
macroevolution and the history of life.
4. Adaptation and Extinction
5. When a species fails to adapt to changing environments,
they become extinct.
4. Patterns of Extinction
Background Extinction
5. Standard rate of extinction ( slow and steady )
Mass Extinction
5. Many species over a relatively short period of time.
3. Rate of Evolution
4. Gradualism
Gradualism
5. Involves a slow, steady change in a particular line of
descent
4. Punctuated Equilibrium
Punctuated Equilibrium
5. Equilibrium that is interrupted by brief periods of more
rapid change.
4. Rapid Evolution After Equilibrium
5. When a small population can evolve faster than the
larger population because of genetic changes spread more
quickly among fewer individuals.
3. Adaptive Radiation and Convergent Evolution
4. Adaptive Radiation
Adaptive Radiation
5. An evolutionary process by which a single species or a
small group of species evolves over a relatively short time
into several different forms that live in different ways.
4. Convergent Evolution
Convergent Evolution
5. When evolution produces similar structures and
characteristics in distantly – related organisms.
3. Coevolution
Coevolution
5. The process by which two species evolve in response to
changes in each other over time
4. Flowers and Pollinators
4. Plants and Herbivorous Insects.
SUMMARY
There are different rates, patterns, and types of evolution.
2. 19.3 Earth’s Early History
3. The Mysteries of Life’s Origins
4. The First Organic Molecules
5. In 1953, chemists Stanley Miller and Harold Urey tried
recreating conditions on the early Earth to see if organic
molecules could be assembled under these conditions.
4. Formation of Microspheres
5. Several hypotheses suggest that structure similar to
proteinoid.
4. Evolution of RNA and DNA
5. One hypothesis suggests that RNA evolved before DNA
4. Production of Free Oxygen
5. Many scientists think that Earth’s early atmosphere may
have been similar to the gases released by a volcano today.
3. Origin of Eukaryotic Cells
4. Endosymbiotic Theory
Endosymbiotic Theory
5. Prokaryotic calls entered those ancestral eukaryotes. The
small prokaryotes began living inside the larger cells.
4. Modern Evidence
5. During the 1960’s, Lynn Margulis of Boston University
noted that mitochondria and chloroplasts contain DNA
similar to bacterial DNA
3. Sexual Reproduction and Multicellularity
4. Significance of Sexual Reproduction
5. Genetic Variation increases the likelihood of a
population’s adapting to changes in an environment.
4. Multicellularity
SUMMARY
5. Multicellular organisms evolved a few hundred million
years after the evolution of sexual reproduction.
There are many hypothesis about molecules and cells from
Earth’s early times.