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spring 2014
SYLLABUS
ORIGIN AND EVOLUTION OF LIFE ON EARTH
SECTION I: ABIOGENESIS AND GEOLOGY
January 14 Introduction to the course
We begin with a first look at the theorie of A.I. Oparin, the Russian biochemist who began the
scientific study of abiogenesis during the first half of the 20th century. His basic hypothesis forms the
theme of the course, although many of the specifics of his proposals are no longer widely accepted.
January 16 Abiogenesis
The study of abiogenesis [life from non-preëxisting life] begins by looking at the first two steps in
the process: the abiogenic synthesis of monomers and, polymerization. Reading: EE chapter 5
(Lazcano).
January 21 Evolution of the first living system
Oparin's theory provides a framework for discussing self-assembly of the first cells and the interface
between non-living and living systems. Once living systems exist, they evolve through the Darwinian
mechanism of Natural Selection.
January 23 The rock cycle
The origins of life is very tightly linked with the active chemistry of Earth's surface. In this lecture
we take a quick look at the dynamics of Earth as a system. Reading: EE chapter 10 (Siever).
January 28 Introduction to Historical Geology
The historical development of the geological timescale and the principles of stratigraphy are
introduced. We review radiometric dating methods and other aspects of dating ancient rocks, on the
Earth and elsewhere.
January 30 Earth origins
The planetesimal or accretion theory for Earth's origin is important for constraining the range of
possible components available for abiogenesis. Much of what we know of the conditions on early Earth
comes from the study of meteorites and the study of nearby planets [comparative planetology]. Reading:
EE chapter 2 (McElroy).
SECTION II: ABIOGENESIS AND EVOLUTION
February 4 • QUIZ 1
February 4 Chemical Evolution I
The abiological synthesis of organic precursors to biomolecules could have occurred on the early
Earth. Or were they generated in space and transported here in comets and meteorites? We examine the
evidence for Earth's earliest environments and the abiological synthesis of simple organic compounds.
February 6 Chemical Evolution II
The synthesis of monomers. What kinds of chemical reactions could have produced simple organic
compounds? Are these chemical reactions compatible with what we know about initial conditions on the
planet? We review the research in this field, starting with a very famous experiment by Stanley Miller
and Harold Urey in 1953.
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February 11 Polymerization: the generation of macromolecules
The organic molecules that are used to build living systems are mostly polymers, larger molecules
made up of smaller subunits. Nucleic acids, lipids, complex carbohydrates and proteins all fit into this
category. The mechanisms and environments that supported the genesis of such molecules is an active
area of origins research today. Reading: EE chapter 3 (Matthews).
February 13 RNA and DNA: The origins of the genetic system
Nucleic acids play a special role in living systems because they contain the genetic information that
is encoded and passed on from organism to organism. How did the genetic code get started and how has
it evolved?
February 18 Cellular metabolism and photosynthesis
Living organisms depend upon the packaging of life into membrane-bound units called cells. Cells
use energy in ways that are common throughout life. How do cells manipulate and control the chemical
energy that is contained in certain molecules? We explore the origins of photosynthesis and related
mechanisms for creating food from inorganic sources. Reading: EE chapter 8 (Margulis).
February 20 Self-Assembly: The bugaboo of abiogenesis
This is where Oparin's theory is weakest - we are long way from understanding how a collection of
molecules can assemble into a living system. We explore some of the different directions this topic
holds at the present time, from materials science and physics to experimental attempts to build actual
cells. Reading: EE chapter 4 (Deamer).
February 25 • QUIZ 2
February 25 Darwinian Evolution
Once a primitive living system was up and running on Earth, the Darwinian process of Natural
Selection provides a well-studied basis for subsequent evolution and development of life.
February 27 Evolutionary Systematics
Introduction to the science and methods of Systematics, the study of diversity of life on Earth;
including classification, taxonomy and species concepts.
March 11 Phylogeny
Building The Tree of Life (TOL). Traditional methods in the construction of phylogeny. Molecular
systematics and molecular clocks.
March 13 On the origin of the Eukaryotic cell
We take a digression into a discussion of the origin of the eukaryotic cell, which probably occurred
during Proterozoic time. This leads into a discussion of a fundamental debate in evolutionary biology
about the significance of lateral gene transfer, symbiogenesis, and reticulate evolution in determining
the fundamental units of biological classification -- Domains and Kingdoms. Reading: EE chapter 8
(Margulis).
SECTION III: PRECAMBRIAN LIFE
March 18 The Archean fossil record.
We survey the fossil record for earliest life on Earth. This includes direct evidence of prokaryotes,
indirect chemical evidence and trace fossils. Reading:EE chapter 6 (Strother & Barghoorn).
March 20 The Proterozoic fossil record
The record of life during the Proterozoic is based on unequivocal microfossils preserved in cherts
and in siliciclastic sedimentary rocks. We survey the kinds of fossils, including chemical fossils and
biomarkers, that characterize the later half of Precambrian time. Reading: EE chapter 9 (McMenamin)
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March 25 • QUIZ 3
March 25 Stromatolites: A modern analog of Precambrian Earth
Stromatolites are organo-sedimentary structures that trap and bind sediment constructed by
communities of mat-building microörganisms. Their occurrence at 3 Ga is pretty strong evidence for the
origins of life by that time. They exist today in the Bahamas and in Western Australia. Reading: EE
chapter 7 (Golubic).
March 27 Life during Ediacaran time.
The organisms that lived during the end of Precambrian time were very different from those that rose
to dominance during the Phanerozoic. This lecture surveys the creatures found during the Ediacaran
Period as we attempt to comprehend their functional biology.
SECTION IV: EARTH SYSTEMS HISTORY
April 1 The evolution of biological complexity
The origin of complex multicellularity leads us to Haeckel’s gastrea theory vs. the
synzoöspore and causes an examination of the position of complex multicellularity within the
eukaryotic supertree.
April 3 The Cambrian Explosion
The sudden appearance of animals at 542 Ma remains one of the great unsolved puzzles of
evolutionary biology.
April 8 Phanerozoic diversity.
The origin and early evolution of the Metazoa with emphasis on the fossil record. We take a brief
look at the pattern of increasing diversity of life on Earth over the last 542 Myr. This pattern is greatly
affected by environmental and climatic changes over millions of years in combination with evolutionary
responses by species to local biological and environmental factors.
April 10 Grand cycles and the evolution of the oceans.
Until just a few years ago, the history of the composition of the oceans was considered to be
essentially unchanged through geologic time. A new paradigm of alternating aragonite and calcite seas
has now taken hold.
April 15 Terrestrial Ecosystems.
We look at the origin and evolution of plant life on land and the effects this has had on the changing
Earth.
April 22 • QUIZ 4
April 22 Evolution of the atmosphere and climate
Changes in O2 and CO2 throughout Earth history have had (and are having) profound effects on all
life on Earth. We review the geological evidence that documents these changes over time and discuss
the impact they have had on the origin and evolution of life on Earth.
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SECTION V: EXOBIOLOGY
April 24 The Gaia Hypothesis
James Lovelock and Lynn Margulis formulated the Gaia Hypothesis to help emphasize the
importance of biological processes that influence the composition of the reactive gasses in Earth's
atmosphere. The Gaia Hypothesis is often misunderstood to be more of a social phenomenon, but we
will use it as a means to study the interaction between life and the Earth's life-sustaining environment.
Reading: EE chapter 1 (Lovelock).
April 29 Of the Plurality of Worlds: S.E.T.I. and the exoplanets
The Greenbank Equation is a generalized calculation about the probability of life elsewhere in the
Universe. The search for extraterrestrial intelligence has received a boost in recent years with the
continuing discovery of (exo)planets outside our own solar system.
May 1 The search for life on Mars
The early Viking experiments and ALH84001. Evidence of water and sedimentary rocks on Mars
today. Course review.
May 12 @ 09:00 – 11:00 FINAL EXAMINATION room 300 Higgins.
Course Particulars
Contact Information.-Lecturer: Paul Strother
Teaching Assistants: Shaina Cohen “cohensv@mail. bc.edu”
Fernando Alverado “blohmf@mail.bc.edu”
Email: paul.strother@bc.edu, please use "GE146" in the subject header.
Office telephone: 617 552-8395 (MWF) or 617 552-1967 (TTh)
Office Hours: 1-2 pm Tuesdays and Thursdays, or by appointment.
Textbooks.-Environmental Evolution (2nd ed.) by Margulis et al. (eds.). MIT Press. EE.
On the Origin of Species by Charles Darwin.
Any additional reading assignments will be announced in class.
Grading.-1. There will be 4 in-class lecture quizzes, each of which is worth 10% of your grade (40% total)
2. Final Examination (35%)
3. Lab grade (25%)
Examination policy.—You may use your class notes during quizzes and exams; however, they must be
written by you and they must be in hardcopy.
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update: January 13, 2014
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