Grotzinger • Jordan
Understanding Earth
Sixth Edition
Chapter 11:
GEOBIOLOGY
Life Interacts with the Earth
© 2011 by W. H. Freeman and Company
Chapter 11
Geobiology:
Life Interacts
with Earth
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.
Lecture Outline
1. The biosphere as a system
2. Microorganisms: nature’s tiny chemists
3. Geobiological events in Earth’s history
4. Evolutionary radiations and mass
extinctions
Lecture Outline
5. Astrobiology: the search for
extraterrestrial life
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.
1. The Biosphere as a System
● Geobiology is the study of the
interactions between the
biosphere and Earth’s
physical environment.
An ecosystem
1. The Biosphere as a System
● Organisms of the ecosystem
● Producers (autotrophs)
● Consumers
(heterotrophs)
1. The Biosphere as a System
● Inputs to the
ecosystem:
what life is made of
● Carbon
● Nutrients
● Water
● Energy
1. The Biosphere as a System
● Processes and outputs:
how organisms live and
grow
● Metabolism
● Photosynthesis
● Respiration
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
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
Example 1: The phosphorous cycle
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Runoff carries
sediment to
rivers, lakes,
and oceans.
Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Runoff carries
sediment to
rivers, lakes,
and oceans.
Plants take
phosphorus
from soil.
Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Runoff carries
sediment to
rivers, lakes,
and oceans.
Plants take
phosphorus
from soil.
Animals eat
plants.
Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Runoff carries
sediment to
rivers, lakes,
and oceans.
Plants take
phosphorus
from soil.
Animals eat
plants.
Decomposers
break down plant
and animal
remains and
return phosphorus
to soil.
Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Plants take
phosphorus
from soil.
Runoff carries
sediment to
rivers, lakes,
and oceans.
Phosphatebearing
compounds in
fertilizers
dissolve in
water.
Animals eat
plants.
Decomposers
break down plant
and animal
remains and
return phosphorus
to soil.
Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Plants take
phosphorus
from soil.
Animals eat
plants.
Runoff carries
sediment to
rivers, lakes,
and oceans.
Phosphatebearing
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.
Wind and rain erode
phosphate-containing
rocks.
Tectonic processes
uplift phosphatecontaining rock
to the surface.
Plants take
phosphorus
from soil.
Animals eat
plants.
Runoff carries
sediment to
rivers, lakes,
and oceans.
Phosphatebearing
compounds in
fertilizers
dissolve in
water.
Phosphate-containing
minerals accumulate to
form phosphatecontaining rocks.
Decomposers
break down plant
and animal
remains and
return phosphorus
to soil.
Phosphorus
leaches from
the soil into water.
Example 2: The sulfur cycle
THE SULFUR CYCLE
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Volcanoes release hydrogen sulfide gas.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Volcanoes release hydrogen sulfide gas.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Volcanoes release hydrogen sulfide gas.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Acid rain increases
weathering of rocks.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Volcanoes release hydrogen sulfide gas.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Acid rain increases
weathering of rocks.
Rivers transport
dissolved sulfur
to water bodies.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Volcanoes release hydrogen sulfide gas.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Acid rain increases
weathering of rocks.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfurbearing compounds
in soil.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Volcanoes release hydrogen sulfide gas.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Acid rain increases
weathering of rocks.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfurbearing compounds
in soil.
Animals eat
plants.
Volcanoes release hydrogen sulfide gas.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Acid rain increases
weathering of rocks.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfurbearing compounds
in soil.
Animals eat
plants.
Decomposers produce
hydrogen sulfide, which
reacts with iron to produce
pyrite.
Volcanoes release hydrogen sulfide gas.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Acid rain increases
weathering of rocks.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfurbearing 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.
Volcanoes release hydrogen sulfide gas.
Rain combines with
hydrogen sulfide to
form sulfuric acid.
Acid rain increases
weathering of rocks.
Tectonic processes
uplift rocks, and
weathering breaks
down sulfurbearing minerals.
Humans burn
fossil fuels,
giving off sulfur
compounds.
Rivers transport
dissolved sulfur
to water bodies.
Plants use sulfurbearing 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.
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
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
Three domains in the tree of life
2. Microorganisms: Nature’s
Tiny Chemists
● Extremophiles: microbes
that “live on the edge”
● Halophiles
● Acidophiles
● Thermophiles
● Anaerobes
Pink: halophiles living in ponds
Dark grey: anaerobes in sediment
2. Microorganisms: Nature’s
Tiny Chemists
● Microorganism-mineral
interactions
● Mineral precipitation
● Mineral dissolution
White: pyrite formed by anaerobes
2. Microorganisms: Nature’s
Tiny Chemists
● Microbial mats
● Stromatolites
3. Geobiological Events
in Earth’s History
● Origin of life and the oldest fossils
● pre-biotic soup
● chemical fossils
● ancient microfossils
● stromatolites
Pre-biotic soup
experiment
Early Archean stromatolites
Proterozoic microfossils
3. Geobiological Events
in Earth’s History
● Origin of Earth’s oxygenated
atmosphere
● cyannobacteria
● banded iron
formations
● eukaryotic algae
● red beds
Proterozoic banded iron formation
Proterozoic eukaryotic algae
Proterozoic red beds
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
Cambrian fossils
Cambrian
radiation
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)
Knife lies on layer marking
End-Cretaceous mass extinction
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
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
Key terms and concepts
Astrobiologist
Autotroph
Banded iron formation
Biogeochemical cycle
Biosphere
Cambrian explosion
Chemoautotroph
Chemofossil
Cyanobacteria
Ecosystem
Evolution
Evolutionary radiation
Extremophile
Gene
Geobiology
Key terms and concepts
Habitable zone
Heterotroph
Metabolism
Microbial mat
Microfossil
Microorganism
Natural selection
Photosynthesis
Red bed
Respiration
Stromatolite