Syllabus
Osher Lifelong Learning Institute at the University of Illinois
Emergence of Life
Instructor: Professor Bruce W. Fouke
Mondays January 25 – March 14, 2016
Course Description
How did Life emerge on Earth? How have Life and Earth co-evolved through geological time? Is Life
elsewhere in the universe? This course reevaluates these questions and the 4 billion-year history of Life
on Earth through the lens of the most up-to-date concepts of the "Tree of Life". The course fundamentally
reconsiders what early Life and evolution looked like before the root of the Tree of Life, the overall
succession of Life that has inhabited our planet, and the search for Life throughout the cosmos. Results
have direct application to a wide variety of pressing societal interests that range from energy and human
medicine to environmental sustainability and space exploration.
Lecture 1. Course Welcome and Overview of Geobiology and Astrobiology
The course begins with a discussion of the historical and philosophical approaches that have been
developed (and are now actively applied) to the completion of scientific research. If done well, scientific
research is both reproducible and predictive in nature. The work of Professor Carl Woese is evaluated as
an example. The basic tools required for this type of scientific reasoning and the ability to overcome the
challenging concepts of scale and complexity are then presented.
Lecture 2. The Tree of Life and Early Earth Environments
The advent of Life on Earth came about as a result of a remarkable confluence of physical, chemical and
biological processes, all of which were intrinsically linked to rapidly changing early Earth environments.
Within this context, cutting-edge approaches in molecular phylogeny have revealed new understandings
of the series of events associated with the emergence of Life, and the possible distribution of Life within
the cosmos. In this process, early assemblages of biochemical components (called the progenote) then
transitioned into individual living cells. These cells then evolved to form the Tree of Life (Bacteria,
Archaea and Eucarya).
Lecture 3. Fossilization and Precambrian Life-Earth Interaction
The accurate interpretation of ancient fossilized life requires the development of crime scene investigative
approaches (CSI). This version of ancient forensic science yields remarkably detailed and complete
reconstructions of the lifestyles of ancient organisms that have been deceased for hundreds, thousands,
millions and even billions of years. These reconstructions, when conducted within the context of ancient
environmental conditions, provide valuable information regarding the evolutionary success of organism
morphology and lifestyle. Therefore, “survival of the fittest” becomes “survival of those fit best”. The
first great natural experiment in this respect, run by the lineage of the Eucarya, was the Ediacaran fauna at
the end of the Precambrian.
Lecture 4. Paleozoic Life After the Advent of Skeletons
A watershed event in the evolution of Life on Earth was the development of external hard skeleton
components, called the Cambrian Explosion at 542 million years before present. The initial successes of
the invertebrates were shortly followed by the appearance of vertebrates with internal skeletons. Life then
utilized these newfound evolutionary capabilities, beginning distinct cycles of radiation, diversification
and extinction, which define the three great Eucarya faunas of the Phanerozoic. A benchmark event in this
process was the evolution of jaws and it’s ensuing influence on predation.
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Lecture 5. Paleozoic Plants, Reptiles and the Transition to Land
In the early Paleozoic plants evolved to leave the water and invade the terrestrial landscape. The shift
meant an abundant food source was readily available on land, and was followed by the transition of
vertebrates into land-based ecosystems. Global increases in CO2 and associated greenhouse warming in
the Pennsylvanian further propelled the success of both prevascular and vascular plants and the related
terrestrial radiation of the three lineages of the reptiles (Anapsids, Synapsids and Diapsids). While
Synapsid predators dominated the late Paleozoic, a massive meteor impact and later environmental
changes reset the ecological and evolutionary stage, opening the door to the rise of the Diapsids.
Lecture 6. Mesozoic Reign of Dinosaurs and the Development of Flight
More than 80% of Life was extinguished during the Permian-Triassic extinction event, opening vast
swaths of ecological opportunity for radiation and diversification of Life during the Mesozoic. Symbiosis,
the mutually beneficial association of two living organisms, was widely utilized during this time period.
A fascinating lineage of Diapsid reptiles rose to replace the Synapsid predators of the late Paleozoic,
evolving multiple distinct types of reptiles. Flight evolved in the process, allowing Pterosaurs to have a
global reach in their annual migrations. Radiation and diversification continued, with the emergence of
the lineage of the Dinosaurs, Archeopteryx and eventually the birds. The end of the Mesozoic was
ushered in by another catastrophic meteor impact, driving the dinosaurs to extinction and opening the
evolutionary stage for the Cenozoic.
Lecture 7. Cenozoic Mammals and Global Environmental Change
With the demise of the Dinosaurs, Mammals rapidly radiated and diversified during the Cenozoic. The
combination of abundant food sources and significant fluctuations in global climate fostered extreme
variations in morphology, body size and interaction with the environment. One distinct advantage that
mammals had over previous groups was the increase in brain size within respect to body size, evidenced
by fossilized mammal skulls. Multiple theories on primate and hominoid evolution are visited, focusing
on recent evidence that sheds new light on intermediate transitional forms in the lineage. This is
contextualized with an overview of the extreme changes in global climate that have taken place
throughout the Cenozoic and into the modern day Earth.
Week 8. Astrobiology and the Search for Life in the Cosmos
All people ask the same fundamental questions: Where are we from? Where are we going? Is there life
elsewhere in the universe? The National Aeronautical and Space Administration (NASA) is dedicated to
search for answers to these questions. The NASA Astrobiology Roadmap describes our current state of
knowledge regarding the origins, evolution, distribution, and future of life in throughout the universe.
These fundamental concepts of life and habitable environments, established upon the modern synthesis of
the Tree of Life, will direct us in recognizing biospheres that might be quite different from our own.
Previous, current and future NASA missions continue to fundamentally reset and enhance our ability to
scientifically answer these vexing questions.
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