1. Life Interacts with Earth
Grotzinger • Jordan
Understanding Earth
Seventh Edition
Chapter 11:
GEOBIOLOGY
Life Interacts with Earth
© 2014 by W. H. Freeman and Company

2. Life Interacts with Earth
Chapter 11
Geobiology:
Life Interacts with Earth

3. About Geobiology
Geobiology is the study of how organisms have been influenced by Earth’s environment.
Earth’s biosphere works as a system.
Micro-organisms play a very important role in Earth processes, including mineral and rock formation and destruction.

4. Lecture Outline The biosphere as a system
2. Microorganisms: nature’s tiny chemists
3. Geobiological events in Earth’s history
4. Evolutionary radiations and mass extinctions

5. Lecture Outline
5. Astrobiology: the search for extraterrestrial life

6. ● Biosphere is the part of our planet that contains all of its
1. The Biosphere as a System
● Biosphere is the part of our
planet that contains all of its
living organisms.
● Ecosystems are composed of
organisms and geologic
components that function in a
balanced, interactive fashion.

7. 1. The Biosphere as a System
● Geobiology is the study of the interactions between the biosphere and Earth’s physical environment.

8. An ecosystem

9. ● Organisms of the ecosystem ● Producers (autotrophs)
1. The Biosphere as a System
● Organisms of the ecosystem
● Producers (autotrophs)
● Consumers (heterotrophs)

11. ● Inputs to the ecosystem: what life is made of ● Carbon ● Nutrients
1. The Biosphere as a System
● Inputs to the ecosystem:
what life is made of
● Carbon
● Nutrients
● Water
● Energy

12. ● Processes and outputs: how organisms live and grow ● Metabolism
1. The Biosphere as a System
● Processes and outputs:
how organisms live and
grow
● Metabolism
● Photosynthesis
● Respiration

15. ● Biogeochemical cycle – a pathway through which a chemical element or
1. The Biosphere as a System
● Biogeochemical cycle –
a pathway through which
a chemical element or
molecule moves between
biologic and environmental
components of an ecosystem.
● Example: greenhouse gasses

16. ● Biogeochemical cycle – a pathway through which a chemical element or
1. The Biosphere as a System
● Biogeochemical cycle –
a pathway through which
a chemical element or
molecule moves between
biologic and environmental
components of an ecosystem.
● Examples: phosphorous and
sulfur cycles

17. Example 1: The phosphorous cycle

18. Tectonic processes
uplift phosphate-
containing rock
to the surface.

19. Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphate-
containing rock
to the surface.

20. Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphate-
containing rock
to the surface.
Runoff carries sediment to rivers, lakes, and oceans.

21. Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphate-
containing rock
to the surface.
Plants take
phosphorus
from soil.
Runoff carries sediment to rivers, lakes, and oceans.

22. Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphate-
containing rock
to the surface.
Plants take
phosphorus
from soil.
Animals eat
plants.
Runoff carries sediment to rivers, lakes, and oceans.

23. Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphate-
containing rock
to the surface.
Plants take
phosphorus
from soil.
Animals eat
plants.
Runoff carries sediment to rivers, lakes, and oceans.
Decomposers break down plant and animal remains and
return phosphorus
to soil.

24. Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphate-
containing rock
to the surface.
Plants take
phosphorus
from soil.
Animals eat
plants.
Runoff carries sediment to rivers, lakes, and oceans.
Phosphate-bearing compounds in fertilizers dissolve in water.
Decomposers break down plant and animal remains and
return phosphorus
to soil.

25. Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphate-
containing rock
to the surface.
Plants take
phosphorus
from soil.
Animals eat
plants.
Runoff carries sediment to rivers, lakes, and oceans.
Phosphate-bearing compounds in fertilizers dissolve in water.
Decomposers break down plant and animal remains and
return phosphorus
to soil.
Phosphorus
leaches from
the soil into water.

26. Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphate-
containing rock
to the surface.
Plants take
phosphorus
from soil.
Animals eat
plants.
Runoff carries sediment to rivers, lakes, and oceans.
Phosphate-bearing compounds in fertilizers dissolve in water.
Decomposers break down plant and animal remains and
return phosphorus
to soil.
Phosphate-containing minerals accumulate to form phosphate-containing rocks.
Phosphorus
leaches from
the soil into water.

27. Example 2: The sulfur cycle

28. Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.

29. Humans burn fossil fuels, giving off sulfur compounds.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.

30. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.

31. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.

32. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.
Acid rain increases
weathering of rocks.

33. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.
Acid rain increases
weathering of rocks.
Rivers transport
dissolved sulfur
to water bodies.

34. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.
Acid rain increases
weathering of rocks.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfur-
bearing compounds
in soil.

35. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.
Acid rain increases
weathering of rocks.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfur-
bearing compounds
in soil.
Animals eat
plants.

36. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.
Acid rain increases
weathering of rocks.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfur-
bearing compounds
in soil.
Animals eat
plants.
Decomposers produce
hydrogen sulfide, which
reacts with iron to produce
pyrite.

37. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.
Acid rain increases
weathering of rocks.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfur-
bearing compounds
in soil.
Animals eat
plants.
Sulfur is leached
from soils and is
transported
to water.
Decomposers produce
hydrogen sulfide, which
reacts with iron to produce
pyrite.

38. Volcanoes release hydrogen sulfide gas.
Humans burn fossil fuels, giving off sulfur compounds.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes uplift rocks, and weathering breaks down sulfur-
bearing minerals.
Acid rain increases
weathering of rocks.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfur-
bearing compounds
in soil.
Animals eat
plants.
Sulfur precipitates
as sulfate and sulfide
minerals.
Sulfur is leached
from soils and is
transported
to water.
Decomposers produce
hydrogen sulfide, which
reacts with iron to produce
pyrite.

39. Thought questions for this chapter
How does the biogeochemical cycle of carbon affect global climate?

40. 2. Microorganisms: Nature’s
Tiny Chemists
● Microbes – single-celled organisms
including bacteria, some fungi and
algae, and protozoa
● most genetically diverse group
● can grow in hostile environments

41. 2. Microorganisms: Nature’s
Tiny Chemists
● Universal tree of life – the hierarchy
of ancestors and descendants of all
life on Earth
● universal ancestor: single root
● three domains of life from the
universal ancestor

42. Three domains in the tree of life

43. 2. Microorganisms: Nature’s
Tiny Chemists
● Extremophiles: microbes
that “live on the edge”
● Halophiles
● Acidophiles
● Thermophiles
● Anaerobes

45. Pink: halophiles living in ponds

46. Dark grey: anaerobes in sediment

47. 2. Microorganisms: Nature’s
Tiny Chemists
● Microorganism-mineral interactions
● Mineral precipitation
● Mineral dissolution

49. White: pyrite formed by anaerobes

50. 2. Microorganisms: Nature’s
Tiny Chemists
● Microbial mats
● Stromatolites

55. ● Origin of life and the oldest fossils ● pre-biotic soup
3. Geobiological Events
in Earth’s History
● Origin of life and the oldest fossils
● pre-biotic soup
● chemical fossils
● ancient microfossils
● stromatolites

56. Pre-biotic soup
experiment

57. Early Archean stromatolites

58. Proterozoic microfossils

59. ● Origin of Earth’s oxygenated atmosphere ● cyanobacteria
3. Geobiological Events
in Earth’s History
● Origin of Earth’s oxygenated
atmosphere
● cyanobacteria
● banded iron formations
● eukaryotic algae
● red beds

61. Archean stromatolites

62. Proterozoic eukaryotic algae

63. Proterozoic red beds

64. 4. Evolutionary Radiations
and Mass Extinctions
● Radiation of life: the Cambrian
explosion
● evolutionary radiation
● work of natural selection
● all major groups formed
● advent of shells on body

65. Cambrian
radiation

66. 4. Evolutionary Radiations
and Mass Extinctions
● Mass extinctions of Phanerozoic life
● Mass extinction at 444 Ma
● Mass extinction at 359 Ma
● End-Permian mass
extinction (251 Ma)
● Mass extinction at 200 Ma
● End-Cretaceous mass
extinction (65 Ma)

68. Knife lies on layer marking End-Cretaceous mass extinction

69. 4. Evolutionary Radiations
and Mass Extinctions
● Mass extinctions of Phanerozoic life
● Mass extinction at 55 Ma
● Paleocene-Eocene
● methane release
● global warming disaster
● radiation of mammals

70. Thought questions for this chapter
During an evolutionary radiation, organisms evolve rapidly. What would the geologic record look like if an evolutionary radiation occurred during an interval represented by an unconformity? How would you distinguish an evolutionary radiation and the effects of an unconformity?

71. 5. Astrobiology: The Search for Extraterrestrial Life
● Places to look for extraterrestrial life
● Habitable zones around stars
● Environments in our solar system
● Mars
● other places

73. Sedimentary rocks on Mars that contain sulfate minerals

74. Thought questions for this chapter
Carbon and water are the basis for all life as we know it. If a giraffe made of silicon walked past one of the Mars Exploration Rovers, how would we know it was alive?

75. Key terms and concepts Autotroph Banded iron formation
Astrobiologist
Autotroph
Banded iron formation
Biogeochemical cycle
Biosphere
Cambrian explosion
Chemoautotroph
Chemofossil
Cyanobacteria
Ecosystem
Evolution
Evolutionary radiation
Extremophile
Gene
Geobiology

76. Key terms and concepts Heterotroph Metabolism Microbial mat
Habitable zone
Heterotroph
Metabolism
Microbial mat
Microfossil
Microorganism
Natural selection
Photosynthesis
Red bed
Respiration
Stromatolite