Transcript The History of Life - Kasson

Chapter 14 The History of Life
Section 1: Fossil Evidence of Change
Section 2: The Origin of Life
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Moon Fun Page
Spare moon buggy
tire! Click on a lesson name to select.
Early Earth / Origin of Life
Earth formed 4.5 billion years ago
Soon after a Mars sized meteor hit
earth, broke stuff free that formed the
moon
For many millions of years
after forming, earth was
bombarded by meteors
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• Life is a continuum extending from the earliest
organisms through various branches to the great
variety of forms alive today.
• Life on Earth began over 3.8 billion ago.
– Earth forms -4.5 billion yrs
– Earth molten / hit by meteors constatly until -4 billion yrs
– Life shows up at -3.8 billion yrs
– Life appeared only 200 million yrs after it was possible for life to exist
200m is really short span in geologic / evolutionary terms!
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Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Land Environments
 Earth formed about 4.6 billion years ago.
 Gravity pulled the densest elements to the
center of the planet.
 After about 500 million years, a solid crust
formed on the surface.
1. (10 pts) Events timeline:
Put the following events in order on a timeline. You don't have to specify when (MYA)
each happened, but do place them proportionately where they belong:
1st Euk cell, 1st animal, O2 accumulates, Pangea starts breaking up, earth forms,
1st cell (bact), -4.5 billion years ago mark, 1st multicelled org., 1st humans, 1st
plant, Present day.
Put these in
order on test
Timeline of Earth History
1st plant
(-450m yrs)
1st Euk Cell
First Prokaryotic cell (-3.8)
-2b yrs
-4.5 billion yrs
-2.25b yrs
-1.5b yrs
1st Multicelled org
1st animal
-500m yrs
Present
1st Human
Formation of Earth
accumulates
-4.5 b yrs
Oxygen
-200,000 yrs
Pangea
-2.7b yrs
-250m yrs
• All life today arises only by the reproduction
of preexisting life, the principle of
biogenesis.
– (Biogenesis = life must come from life, can’t spontaneously appear)
• Although there is no evidence that spontaneous
generation occurs today, conditions on the early Earth
were very different.
– There was very little atmospheric oxygen to
attack complex molecules.
– Energy sources, such as lightning, volcanic
activity, and ultraviolet sunlight, were more
intense than what we experience today.
3. (2 pts) Explain the key factors of the early earth environment that would possibly have
enabled a first cell to form .
Early atmosphere not like the
present
-No Oxygen
-CO2, H20,N2, CH4
More energy at the earth’s surface
-UV (sun more intense)
-Volcanoes
-Lightning
***No oxygen is key to origin of life***
O2 is a powerful oxidizer and would
have degraded any organic
molecules that would have
happened to form
Obviously reactive stuff
Without O2 organic molecules built up on early earth:
Organic molecules formed in oceans and accumulated
The oceans became big pools of organic molecules
Also additional organic mater
was delivered to early earth via
meteors
Meteor jam-packed with
organic molecules
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Atmosphere
 The gases that likely made up the atmosphere are
those that were expelled by volcanoes.
 Water vapor (H2O)
 Carbon dioxide (CO2)
 Sulfur dioxide (SO2)
 Carbon monoxide (CO)
 Hydrogen sulfide (H2S)
 Hydrogen cyanide (HCN)
 Nitrogen (N2)
 Hydrogen (H2)
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
The Geologic Time Scale
 The geological time scale is a model that
expresses the major geological and biological
events in Earth’s history.
 The geologic time scale is divided into the
Precambrian time and the Phanerozoic eon.
 Eras of the Phanerozoic eon include the
Paleozoic, Mesozoic, and Cenozoic eras.
 Each era is divided into one or more periods.
2. (4 pts) Eras timeline
Put the eras in chronological order on a timeline. Show proportionately how long each
one lasted
4. (4 pts) Match the events to the era
_____Bacteria evolve ability to do photosynthesis
A.
_____Koala bears show up (type of mammal)
B.
_____T. rex vs. velociraptor battles common
C.
_____First amphibians appear
D.
• By comparing different sites, geologists have
established a geologic time scale with a
consistent sequence of historical periods.
– These periods are grouped into four eras:
•
•
•
•
Precambrian: oldest, first cell – simple animal
Paleozoic: earliest fish, amphib’s, reptiles, mammlas
Mesozoic: age of dinosaurs
Cenozoic: classes of mammals, birds appear - today
• Boundaries between geologic eras and
periods correspond to times of great change,
especially mass extinctions, not to periods
of similar length.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Precambrian
 Nearly 90 percent of Earth’s entire history,
stretching from the formation of Earth to
the beginning of the Paleozoic era about
542 million years ago
 Autotrophic prokaryotes enriched the
atmosphere with oxygen.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
The Paleozoic Era
 The ancestors of most major animal groups
diversified in what scientists call the Cambrian
explosion.
 Life in the oceans continued to evolve at the
end of the Cambrian period.
 Fish, land plants, and insects appeared during
the Ordovician and Silurian periods.
 The first tetrapods emerged in the Devonian.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
 A mass extinction ended the Paleozoic era
at the end of the Permian period.
 Between 60 and 75 percent of the species
alive went extinct.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
The Mesozoic Era
 Mammals and dinosaurs first appeared late
in the Triassic period, and flowering plants
evolved from nonflowering plants.
 Birds evolved from a group of predatory
dinosaurs in the middle of the Jurassic period.
 About 65 million years ago, a meteorite
struck Earth.
5. Explain the best theory that explains the
extinction of the dinosaurs
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
The Cenozoic Era
 Mammals became the dominant land animals.
 After the mass extinction at the end of the
Mesozoic era, mammals of all kinds began
to diversify.
Most orders of modern mammals, including
primates, appeared 50-60 million years
ago.
• Humans diverged from other primates only
5 million years ago
Humans species showed up only ~200,000 yrs ago
5. Explain how all of the continents can be billions of years old, yet all of the ocean floor
crust is only several million years old
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
 Plate tectonics describes the movement of several
large plates that make up the surface of Earth.
 These plates, some of which contain continents,
move atop a partially molten layer of rock
underneath them.
The continents are “islands” of light rock that float on the liquid mantle below
Mid ocean ridges generate new
crust that keeps continents
moving
• The continents drift about Earth’s surface on
plates of crust floating on the hot mantle.
Earthquakes /
volcanoes form at
plate boundaries
In the movie
“2012” the sun
sends out extra
radiation that
warms earths
core “like a
microwave”
Which causes
plates to start
moving around
• About 250 million years ago, all the land
masses were joined into one supercontinent,
Pangaea, with dramatic impacts on life on
land and the sea.
See note book file for proportional timeline
6. Explain why the “Fossil record” is considered to be very strong evidence in support of the
theory of evolution by natural selection.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Clues in Rocks
 A fossil is any preserved evidence of an
organism.
 Most organisms decompose before they
have a chance to become fossilized.
The fossil record is the ordered array in
which fossils appear within sedimentary
rocks.
7. Describe four different types of fossils:
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
• Trace fossils: consist of footprints, burrows,
or other impressions left in sediments by the
activities of animals.
• These rocks are in
essence fossilized
behavior.
– These dinosaur tracks
provide information
about its gait.
Mold/ Cast
Mold:
Impression left by organism (- impression)
Cast:
Object created when sediment fills mold (+ imp.)
Replacement: original material of
organism is replaced with
mineral crystals
-leaves detailed replicas
• Petrified fossils:
• Under the right conditions minerals dissolved in
groundwater seep into the tissues of dead
organisms, replace its organic material, and
create a cast in the shape of the organism.
Amber fossils
-Organism gets trapped in tree sap that
dehydrates/ hardens over time into amber
• Organic Remains type fossils
• If an organism dies in a place where
decomposition cannot occur, then the entire
body, including soft parts may be preserved as a
fossil.
– These organisms have been frozen in ice, or
preserved in acid bogs.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Fossil Formation
 Nearly all fossils are formed in sedimentary
rock.
 The sediments build up until they cover the
organism’s remains.
 Minerals replace the organic matter or fill the
empty pore spaces of the organism.
Finding Fossils in SE MN
Olmsted and Goodhue Co.’s have many road cuts that expose the
“Decorah Shale” (Shale rock is a type of sedimentary
rock formed from
mud/clay that is compacted together by pressure over time)
Google: “Fossil Collecting in Twin Cities
area” for more info (look for pdf)
Decorah shale is grey / green
8. Explain why the fossil record is very
incomplete:
The fossil record is a substantial, but incomplete, chronicle of
evolutionary history
• The discovery of a fossil depends on a sequence
of improbable events.
– First, the organism must die at the right place and time
to be buried in sediments favoring fossilization.
– The rock layer with the fossil must escape processes
that destroy or distort rock (e.g., heat, erosion).
– The fossil then has only a slight chance that it will be
exposed by erosion of overlying rock.
– Finally, there is only a slim chance that someone will
find the fossil on or near the surface before it is
destroyed by erosion too.
9. How do scientists know how old fossils are? /
i.e. How do scientists date fossils?
A. Relative dating:
B. Absolute dating
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Dating fossils
 Relative dating is a
method used to
determine the age of
rocks by comparing
them with those in
other layers.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Absolute Dating
 Uses the decay of
radioactive isotopes
to measure the age
of a rock
 Radioactive
isotopes that can be
used for radiometric dating are found only in
igneous or metamorphic rocks.
10. What are the proposed steps to explain how a first cell could have formed?
How to make a cell:
• Under one hypothetical scenario this occurred
in four stages:
(1) the creation of small organic molecules;
(2) joining these small molecules into polymers:
(3) origin of self-replicating molecules;
(4) packaging of these molecules into “protobionts.”
11. What is “Spontaneous generation” and how did Louis Pasteur disprove it?
Chapter 14
The History of Life
14.2 The Origin of Life
Origins: Early Ideas
 Spontaneous generation is the idea that life arises
from nonlife.
 Francesco Redi, an Italian scientist, tested the idea
that flies arose spontaneously from rotting meat.
Chapter 14
The History of Life
14.2 The Origin of Life
 The theory of
biogenesis states
that only living
organisms can
produce other living
organisms.
 Louis Pasteur
designed an
experiment to show
that biogenesis was
true even for
microorganisms.
Chapter 14
The History of Life
14.2 The Origin of Life
Origins: Modern Ideas
 Simple organic molecule formation
 The primordial soup hypothesis was an
early hypothesis about the origin of life.
 Organic molecules could have been
synthesized from simple reactions.
 UV light from the Sun and electric
discharge in lightning might have been
the primary energy sources.
12. What was the Miller-Urey experiment and what did it show?
Chapter 14
The History of Life
14.2 The Origin of Life
 Stanley Miller and
Harold Urey were the
first to show that simple
organic molecules
could be made from
inorganic compounds.
Stanley/ Miller
provided evidence
that organics could
have formed on
early earth
Chapter 14
The History of Life
14.2 The Origin of Life
Making Proteins
 Life requires proteins.
 One possible mechanism for the formation of proteins
would be if amino acids were bound to a clay particle.
13. What do most scientists consider the first genetic material was made of? Why?
Chapter 14
The History of Life
14.2 The Origin of Life
Genetic Code
 Many biologists consider RNA to have
been life’s first coding system.
 Other researchers have proposed that clay
crystals could have provided an initial
template for RNA replication.
• Living cells may have been
preceded by protobionts,
aggregates of abiotically
produced molecules (with
lipids).
• Protobionts do not reproduce
precisely, but they do maintain
an internal chemical
environment from their
surroundings and may show
some properties associated
with life, metabolism, and
excitability.
• Early protobionts with selfreplicating, catalytic RNA
would have been more
effective at using resources
and would have increased in
number through natural
selection
• Once primitive
RNA genes and
their
polypeptide
products were
packaged within
a membrane, the
protobionts
could have
evolved as
units.
Chapter 14
The History of Life
14.2 The Origin of Life
Cellular Evolution
 Scientists hypothesize that the first cells were
prokaryotes.
Chapter 14
The History of Life
14.2 The Origin of Life
Photosynthesizing Prokaryotes
 Archaea are autotrophic.
 They do not obtain their energy from the Sun.
 Archaea also do not need or produce oxygen.
Chapter 14
The History of Life
14.2 The Origin of Life
 Many scientists think that photosynthesizing
prokaryotes evolved not long after the
archaea.
 Prokaryotes, called cyanobacteria, have been
found in rocks as old as 3.5 billion years.
14. Explain the endosymbiont theory and provide 2 pieces of evidence that support this theory:
Chapter 14
The History of Life
14.2 The Origin of Life
The Endosymbiont Theory
 The ancestors of eukaryotic cells lived in
association with prokaryotic cells.
 The relationship between the cells
became mutually beneficial, and the
prokaryotic symbionts became organelles
in eukaryotic cells.
 This theory explains the origin of
chloroplasts and mitochondria.
Chapter 14
The History of Life
14.2 The Origin of Life
• ***Several lines of evidence support a
close similarity between bacteria and the
chloroplasts and mitochondria of
eukaryotes***.
– 1. These organelles and bacteria are similar is
size.
– 2. Enzymes and transport systems in the inner
membranes of chloroplasts and mitochondria
resemble those in the plasma membrane of
modern prokaryotes.
– 3. Replication by mitochondria and chloroplasts
resembles binary fission in bacteria.
– 4. The single circular DNA in chloroplasts and
mitochondria lack histones and other proteins, as
in most prokaryotes.
– 5. Both organelles have their own transfer RNAs,
ribosomes, and other molecules for transcription
of their DNA and translation of mRNA into
proteins.
– 6. The ribosomes of both chloroplasts and
mitochondria are more similar to those of
prokaryotes than to those in the eukaryotic
cytoplasm that translate nuclear genes.
Prod: “Origin of the first cell”
Create a booklet or poster with text & pictures and
multiple pages (or a comic book format) to
describe how first cell could have arisen.
Things to include:
1. Making small molecules (What was early earth
like? What was missing!?!)
2. Making proteins (polymers…how?)
3. Role of RNA
4. Origin of protobionts
5. Origin of Prokaryotes
6. Origin of Eukaryotes (endosymbiont theory)
Chapter 14
The History of Life
Chapter Resource Menu
Chapter Diagnostic Questions
Formative Test Questions
Chapter Assessment Questions
Standardized Test Practice
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Glencoe Biology Transparencies
Image Bank
Vocabulary
Animation
Click on a hyperlink to view the corresponding lesson.
Chapter 14
The History of Life
Chapter Diagnostic
Questions
Which is an example of the theory of
spontaneous generation?
A. Tadpoles become frogs.
B. A starfish can grow from a severed arm.
C. Damp hay and corn create mice.
D. From a tiny acorn, an oak can grow.
Chapter 14
The History of Life
Chapter Diagnostic
Questions
What gas do scientists think was absent from
Earth’s early atmosphere?
A. sulfur
B. nitrogen
C. oxygen
D. water vapor
Chapter 14
The History of Life
Chapter Diagnostic
Questions
In which period did the first land vertebrates
appear?
A. Cambrian
B. Devonian
C. Triassic
D. Mesozoic
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
14.1 Formative
Questions
Which geological change during the Mesozoic
era had the greatest effect in shaping the
course of evolution?
A. plate tectonics
B. extensive glaciation
C. increased volcanic activity
D. meteorite impact
Chapter 14
The History of Life
14.2 Formative
Questions
At one time people believed that mold growing
on a piece of cheese was created by the
cheese. This is the idea of __________.
A. biogenesis
B. transgenesis
C. primordial generation
D. spontaneous generation
Chapter 14
The History of Life
14.2 Formative
Questions
According to the endosymbiont theory, what may
have happened to a prokaryotic cell that entered
a host cell?
A. It was digested by the host cell.
B. It became an organelle in the host cell.
C. It became a harmful parasite in the host cell.
D. It was removed from the host cell by
exocytosis.
Chapter 14
The History of Life
14.2 Formative
Questions
An ancient prokaryote containing photosynthetic
pigments that was engulfed by a host cell may
have become a _________.
A. chloroplast
B. lysosome
C. centriole
D. ribosome
Chapter 14
The History of Life
Chapter Assessment
Questions
Which is the half-life of the radioactive isotope
shown in the graph?
A. 18 years
B. 36 years
C. 54 years
D. 72 years
Chapter 14
The History of Life
Chapter Assessment
Questions
Study the graph. Determine the age of a rock if
it contained 40% C-14.
A. 2,857.5 years
B. 7,576 years
C. 11,460 years
D. 5,730 years
Chapter 14
The History of Life
Chapter Assessment
Questions
Use the illustration to infer what Pasteur’s
experiment showed?
Chapter 14
The History of Life
Chapter Assessment
Questions
A. Tilted bottles often spill.
B. Microorganisms do not grow in flasks.
C. Sterile liquids cannot spoil.
D. Microorganisms can enter the tilted flask.
Chapter 14
The History of Life
Standardized Test
Practice
Which factor made it unlikely that life existed on
Earth 4 billion years ago?
A. absence of oxygen
B. absence of food
C. intense heat
D. intense sunlight
Chapter 14
The History of Life
Standardized Test
Practice
For which fossil might a paleontologist most
likely use carbon-14 to determine its age?
A. fossilized microbes in volcanic rock
B. dinosaur footprints found in sedimentary
rock
C. marine fossils found in a deep sedimentary
layer
D. a woolly mammoth frozen in a glacier since
the last Ice Age
Chapter 14
The History of Life
Standardized Test
Practice
Beryllium-10 (Be-10) has a half life of about
1.5 million years. If a sample is analyzed and
determined to contain ¼ of the original Be-10,
what is the age of the sample?
A. 750,000 years
B. 3 million years
C. 4.5 million years
D. 6 million years
Chapter 14
The History of Life
Standardized Test
Practice
Which provides the best evidence that a
meteorite struck the earth 65 million years
ago?
A. a large crater that was found
B. a layer containing high levels of iridium
C. the sudden appearance of mammals
D. the sudden disappearance of dinosaurs
Chapter 14
The History of Life
Standardized Test
Practice
In this experiment
using water and the
gases to simulate
Earth’s early
atmosphere, which
was not one of the
final products?
Chapter 14
The History of Life
Standardized Test
Practice
A. amino acids
B. nucleotides
C. RNA molecules
D. sugar molecules
Chapter 14
The History of Life
Standardized Test
Practice
Why do scientists believe that archea are
the closest relatives to Earth’s first cells?
A. They are eukaryotes.
B. They contain DNA.
C. They carry out photosynthesis.
D. They live in extreme environments.
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