Understanding Earth Sixth Edition Chapter 11: GEOBIOLOGY Life Interacts with the Earth © 2011 by W. H. Freeman and Company Grotzinger Jordan

Chapter 11 Geobiology: Life Interacts with Earth

About Geobiology Geobiology is the study of how organisms have been influenced by Earth’s environment. Geobiology is the study of how organisms have been influenced by Earth’s environment. Earth’s biosphere works as a system. Earth’s biosphere works as a system. Micro-organisms play a very important role in Earth processes, including mineral and rock formation and destruction. 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 planet that contains all of its living organisms. living organisms. ● Ecosystems are composed of organisms and geologic organisms and geologic components that function in a components that function in a balanced, interactive fashion. 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 what life is made of ● Carbon ●Nutrients ● Nutrients ●Water ● Water ● Energy

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

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

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

Example 1: The phosphorous cycle

Tectonic processes uplift phosphate- containing rock to the surface.

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

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

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

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

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

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

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

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

THE SULFUR CYCLE Example 2: The sulfur cycle

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

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

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

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

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

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

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

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

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

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

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

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

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

Three domains in the tree of life

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

Pink: halophiles living in ponds

Dark grey: anaerobes in sediment

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

White: pyrite formed by anaerobes

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

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

Pre-biotic soup experiment

Early Archean stromatolites

Proterozoic microfossils

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

Proterozoic banded iron formation

Proterozoic eukaryotic algae

Proterozoic red beds

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

Cambrian fossils

Cambrian radiation radiation

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

Knife lies on layer marking End-Cretaceous mass extinction

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

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

AstrobiologistAutotroph Banded iron formation Biogeochemical cycle Biosphere Cambrian explosion ChemoautotrophChemofossilCyanobacteriaEcosystemEvolution Evolutionary radiation ExtremophileGeneGeobiology Key terms and concepts

Habitable zone HeterotrophMetabolism Microbial mat MicrofossilMicroorganism Natural selection Photosynthesis Red bed RespirationStromatolite Key terms and concepts