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

Life Interacts with Earth 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 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

● 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.

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

An ecosystem

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

● 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

● 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

● 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

● 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

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.

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

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.

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.

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.

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.

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.

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.

Example 2: The sulfur cycle

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

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

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

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.

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.

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.

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.

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.

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.

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.

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.

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

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

● 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

Pre-biotic soup experiment

Early Archean stromatolites

Proterozoic microfossils

● 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

Archean stromatolites

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 body

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

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?

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

Sedimentary rocks on Mars that contain sulfate minerals

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?

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

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