1. Modified by M. Elizabeth February 2008

2. Chapter 14 The History of Life
Section 1: Fossil Evidence of Change
Section 2: The Origin of Life

3. Earth formed about 4.6 billion years ago as a molten planet.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Land Environments
Earth formed about 4.6 billion years ago as a molten planet.
Gravity pulled the densest elements to the center of the planet during the first 500 million years.
After about 4 billion years, a solid crust formed on the surface, but molten outer core remains.
Volcanoes erupted, giving off gases and forming the early atmosphere.

4. Layers of Earth

5. 14.1 Fossil Evidence of Change
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)

6. A fossil is any preserved evidence of an organism.
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.
Are found in the earth’s crust – the very uppermost part of the earth that is exposed to the surface, or lying immediately below the oceans.

7. 14.1 Fossil Evidence of Change
Chapter 14
The History of Life
14.1 Fossil Evidence of Change

8. Chapter 14
The History of Life

9. Nearly all fossils are formed in sedimentary rock.
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Fossil Formation
The three most common material that fossils form in are sedimentary rock, amber, and ice.
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.

11. The Best Crust for Fossils
Sedimentary Rocks are the best crust for fossil formations;
Example: The Grand Canyon. Strata = Layers of sediment so its called sedimentary rock

12. Rocks contain clues to the Earth’s past.

13. Does not give exact ages
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.
Does not give exact ages

14. Law of Superposition:Youngest on Top
An undeformed sedimentary rock layer is older than the layers above it and younger than the layers below it D C B A

15. Radioactive isotopes that can be
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
Radiometric Dating
Uses the decay of radioactive isotopes to accurately measure the age of a rock
Radioactive isotopes that can be
used for radiometric dating are found only in
igneous or metamorphic rocks.

16. The Geologic Time Scale
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.

17. Geologic Time Notations
ya – Years Ago
mya – Million of years ago
bya – Billion years ago
Eons to Eras to Periods once life on Earth
Time before life = Precambrian
2 Eons Proterozoic and Phanerozoic
Phanerozoic = 3 eras
Precambrian Time Paleozoic ERA Mesozoic ERA Cenozoic ERA

18. Era word roots Geologist use the clues in some of these words.
For example:
zoic refers to animal life
paleo means ancient
meso means middle,
ceno means recent.
So the relative order of the three youngest eras, first Paleoozoic, then Mesozoic, then Cenoozoic, is straightforward.

19. Autotrophic prokaryotes enriched the atmosphere with oxygen.
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.
Visualizing Geologic Time

20. The first tetrapods emerged in the Devonian.
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.

21. 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 land species alive went extinct and 96 of all marine species. Why were marine organisms more affected?
The greatest of the five major mass extinctions was the Permian Mass Extinction .
The five major mass extinctions: Ordovician, Devonian, Permian, Triassic and Cretaceous.

22. The Mesozoic Era (Triassic, Jurassic, Cretaceous)
Chapter 14
The History of Life
14.1 Fossil Evidence of Change
The Mesozoic Era (Triassic, Jurassic, Cretaceous)
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. A hypothesis that this resulted in the K/T Mass Extinction ending the Cretaceous Period.

23. 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.

24. Chapter 14
The History of Life

25. Mammals became the dominant land animals.
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.

26. 14.2 The Origin of Life Origins: Early Ideas
Chapter 14
The History of Life
14.2 The Origin of Life
Origins: Early Ideas
Spontaneous generation is the mistaken idea that life arises from non-life.
Francesco Redi, an Italian scientist, tested the idea that flies arose spontaneously from rotting meat.

27. 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.

28. Simple organic molecule formation
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 to start the chemical reactions of gases in early atmosphere.

29. 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.
Later, scientists found that hydrogen cyanide could be formed from even simpler molecules in simulated early Earth environments.

30. Chapter 14
The History of Life

31. Four Requirements of Life
Chapter 14
The History of Life
14.2 The Origin of Life
Four Requirements of Life
Simple organic molecules, the building blocks of life.
A way to synthesize proteins from amino acids.
A coding system for replicating proteins – such as DNA.
A way to form cells from molecules - membranes

32. Life requires proteins.
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.

33. Some RNA sequences appear to have changed very little through time.
Chapter 14
The History of Life
14.2 The Origin of Life
Genetic Code
Some RNA sequences appear to have changed very little through time.
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.

34. Scientists hypothesize that the first cells were prokaryotes.
Chapter 14
The History of Life
14.2 The Origin of Life
Cellular Evolution
Scientists hypothesize that the first cells were prokaryotes.
Many scientists think that modern prokaryotes called archaea are the closest relatives of Earth’s first cells.

35. Archaea are autotrophic.
Chapter 14
The History of Life
14.2 The Origin of Life
Domain Archaea
Archaea are autotrophic.
They do not obtain their energy from the Sun.
Archaea also do not need or produce oxygen.

36. Chapter 14
The History of Life
14.2 The Origin of Life
Many scientists think that photosynthesizing prokaryotes part of evolved not long after the archaea.
Prokaryotes, such as cyanobacteria, have been found in rocks as old as 3.5 by.
Photosynthesizing bacteria like cyanobacteria dramatically changed the atmosphere – increasing oxygen content for you and I.

37. The Endosymbiont 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.
Three properties of chloroplasts and mitochondria shared with prokaryotes: circular DNA, similar ribosomes, reproduced by fission.

38. Chapter 14
The History of Life
14.2 The Origin of Life

39. Chapter Resource Menu Chapter Diagnostic Questions
The History of Life
Chapter Resource Menu
Chapter Diagnostic Questions
Formative Test Questions
Chapter Assessment Questions
Standardized Test Practice
biologygmh.com
Glencoe Biology Transparencies
Image Bank
Vocabulary
Animation
Click on a hyperlink to view the corresponding lesson.

40. Which is an example of the theory of spontaneous generation?
Chapter 14
The History of Life
Chapter Diagnostic Questions
Which is an example of the theory of
spontaneous generation?
Tadpoles become frogs.
A starfish can grow from a severed arm.
Damp hay and corn create mice.
From a tiny acorn, an oak can grow.

41. What gas do scientists think was absent from Earth’s early atmosphere?
Chapter 14
The History of Life
Chapter Diagnostic Questions
What gas do scientists think was absent from
Earth’s early atmosphere?
sulfur
nitrogen
oxygen
water vapor

42. In which period did the first land vertebrates appear?
Chapter 14
The History of Life
Chapter Diagnostic Questions
In which period did the first land vertebrates
appear?
Cambrian
Devonian
Triassic
Mesozoic

43. In which type of rock do paleontologists search for fossils?
Chapter 14
The History of Life
14.1 Formative Questions
In which type of rock do paleontologists search
for fossils?
igneous
metamorphic
sedimentary
volcanic

44. Which dating method determines the age of
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?
absolute dating
geological dating
relative dating
sedimentary dating

45. Which geological change during the Mesozoic
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?
plate tectonics
extensive glaciation
increased volcanic activity
meteorite impact

46. At one time people believed that mold growing
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 __________.
biogenesis
transgenesis
primordial generation
spontaneous generation

47. According to the endosymbiont theory, what may
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?
It was digested by the host cell.
It became an organelle in the host cell.
It became a harmful parasite in the host cell.
It was removed from the host cell by
exocytosis.

48. An ancient prokaryote containing photosynthetic
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 _________.
chloroplast
lysosome
centriole
ribosome

49. Which is the half-life of the radioactive isotope shown in the graph?
Chapter 14
The History of Life
Chapter Assessment Questions
Which is the half-life of the radioactive isotope
shown in the graph?
18 years
36 years
54 years
72 years

50. Study the graph. Determine the age of a rock if it contained 40% C-14.
Chapter 14
The History of Life
Chapter Assessment Questions
Study the graph. Determine the age of a rock if
it contained 40% C-14.
2,857.5 years
7,576 years
11,460 years
5,730 years

51. Use the illustration to infer what Pasteur’s experiment showed?
Chapter 14
The History of Life
Chapter Assessment Questions
Use the illustration to infer what Pasteur’s
experiment showed?

52. Tilted bottles often spill. Microorganisms do not grow in flasks.
Chapter 14
The History of Life
Chapter Assessment Questions
Tilted bottles often spill.
Microorganisms do not grow in flasks.
Sterile liquids cannot spoil.
Microorganisms can enter the tilted flask.

53. Which factor made it unlikely that life existed on
Chapter 14
The History of Life
Standardized Test Practice
Which factor made it unlikely that life existed on
Earth 4 billion years ago?
absence of oxygen
absence of food
intense heat
intense sunlight

54. For which fossil might a paleontologist most
Chapter 14
The History of Life
Standardized Test Practice
For which fossil might a paleontologist most
likely use carbon-14 to determine its age?
fossilized microbes in volcanic rock
dinosaur footprints found in sedimentary
rock
marine fossils found in a deep sedimentary
layer
a woolly mammoth frozen in a glacier since
the last Ice Age

55. Beryllium-10 (Be-10) has a half life of about
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?
750,000 years
3 million years
4.5 million years
6 million years

56. Which provides the best evidence that a
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 large crater that was found
a layer containing high levels of iridium
the sudden appearance of mammals
the sudden disappearance of dinosaurs

57. In this experiment using water and the gases to simulate Earth’s early
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?

58. amino acids nucleotides RNA molecules sugar molecules
Chapter 14
The History of Life
Standardized Test Practice
amino acids
nucleotides
RNA molecules
sugar molecules

59. Why do scientists believe that archea are
Chapter 14
The History of Life
Standardized Test Practice
Why do scientists believe that archea are
the closest relatives to Earth’s first cells?
They are eukaryotes.
They contain DNA.
They carry out photosynthesis.
They live in extreme environments.

60. Glencoe Biology Transparencies
Chapter 14
The History of Life
Glencoe Biology Transparencies

61. Chapter 14
The History of Life
Image Bank

62. Section 1 Vocabulary fossil paleontologist relative dating
Chapter 14
The History of Life
Vocabulary
Section 1
fossil
paleontologist
relative dating
law of superposition
radiometric dating
half-life
geologic time scale
era
period
Cambrian explosion
K-T boundary
plate tectonics

63. Section 2 Vocabulary spontaneous generation theory of biogenesis
Chapter 14
The History of Life
Vocabulary
Section 2
spontaneous generation
theory of biogenesis
endosymbiont theory

64. Visualizing Geologic Time Continental Drift Miller-Urey Experiment
Chapter 14
The History of Life
Animation
Visualizing Geologic Time
Continental Drift
Miller-Urey Experiment