Geology 144:
The History of Ecosystems
Winter 2008

Introduction
The purpose of this course is to introduce students to history and its underlying principles, with an emphasis on the history of ecosystems.  The aim is to provide a framework for predicting and regulating the human-dominated ecosystems of the future.  Because ecosystems are special cases of economic systems, the course will begin with an introduction to the structure and assembly of economies generally.  Other topics included are the history of biological diversity, development of geochemical cycles and energy relations in the biosphere, extinction, invasion, the role of feedbacks, origins of new ways of life, and the roles of predators, mutualists, parasites, and primary producers.

Assignments
Students will be asked to write three short papers.  The first two, not to exceed one page in length, will be brief critical reviews of topical papers.  The third, which will be of not more than two pages in length and will serve as the final examination, will be the reconstruction of an ancient ecosystem of the student's choice.

Papers will be expected to be polished, well-argued essays, grammatically and orthographically correct, in which all sources cited must be published articles, chapters or books.  All such sources must be cited in full, and all sources in the bibliography must be cited in the text.  All writing must be original; plagiarism is strictly prohibited and, if discovered, will result in failure.

Detailed course outline

I.   Ecosystems as economies

A.  Economic systems:  interacting, metabolizing, responsive entities, parts of a whole

B.  Characteristics of economies:  participants are themselves economies; participants interact, coexist, have common as well as conflicting interests, compete for resources

C.  Resources:  inorganic nutrients, energy, the participants themselves and their products

D.  Variations:  diversity, division of labor, size

E.   Processes at work in economies

1.  Competition:  conflict of interest

2.  Cooperation:  common interest

3.  Inequality during interaction:  dominants and their disproportionate effects on the composition, distribution, and characteristics of participants

4.  Adaptation:  responding to and resisting change, bringing about change

5.  Disturbance:  external and internal events resulting in economic change; parallel with genetic mutation

6.  Production

7.  Consumption

8.  Recycling

9.  Invasion

10.  In situ change

11.  Extinction

12.  Positive and negative feedback

 

II.  Methods of inquiry

A.  How modern ecosystems function

B.  How ecosystems vary according to habitat and geography

C.  How ecosystems interact with each other across geographical and ecological boundaries

D.  The rock record and fossil record, their possibilities and limitations

E.  The principle of uniformitarianism:  inferring the past from the present, qualifications and difficulties

 

III.  Review of living ecosystems

A.  Survey of modern terrestrial, freshwater, and marine systems (tundra, temperate forests, temperate grasslands, deserts, tropical dry forest, tropical rain forest, savanna, marshes and swamps, the intertidal zone worldwide, the benthic photic zone, the deep sea, life in sediments, life in rocks, the marine pelagic realm, the freshwater benthos, the freshwater pelagic realm

B.  Geographical and ecological patterns

1.  Productivity:  a function of altitude, latitude, bathymetry, rainfall, temperature

2.  Consumption

3.  The establishment of geographical and ecological boundaries:  polar-temperate-tropical, forest-grassland-desert; intertidal-sublittoral-abyssal-hadal; benthic-pelagic; freshwater-brackish-marine; dispersal barriers

4.  Patterns of energy conversion and recycling

5.  Patterns in diversity

6.  Metabolism in relation to temperature, salinity, oxygen, carbon dioxide, seasonality

 

IV.  Ancient ecosystems

A.  Ecosystem history in the last 65 million years (the Cenozoic era)

1.  Geographic history of the Cenozoic

2.  Patterns of Cenozoic extinction:  end-Paleocene deep-sea event, end-Eocene events, extinctions of the middle and late Miocene, events of the Pliocene and early Pleistocene; geographical refuges from extinction

3.  Patterns of biotic exchange:  the Great American interchange of the Pliocene and Pleistocene; movements across the Bering land bridge and the role of Asia as the source for much of the terrestrial biota; movements across  the temperate and tropical Pacific and Atlantic Oceans; circum-Antarctic movements; trans-Arctic interchange

4.  Assembly and history of particular biotas:  the temperate North Pacific, the temperate North Atlantic, the tropical marine faunas; the tropical American rainforest; the role of humans in different habitats and different parts of the world

B.  Assembly of ecosystems in deep time

1.  Autotrophy, photosynthesis, and heterotrophy

2.  Evolution of the nitrogen cycle

3.  Controls of the silica and calcium cycles

4.  The history of oxygen and carbon dioxide

5.  The history of consumption: predation, detritivory, parasitism, herbivory

6.  The history and role of mutualisms and other forms of cooperation:  the origin of the eukaryotic cell, plant-animal and plant-fungal partnerships, evolution of agriculture

7.  The Gaia hypothesis:  the biosphere and homeostat

8.  The history of ecosystem expansion:  increased exploitation of space within sediments and rocks, expansion of the pelagic realm and the rise of plankton, exploitation of the land, transitions between tropical and temperate zones, invasion of the high intertidal and deep sea

 C.  The causes and consequences of the great extinctions

1.  The mass extinctions:  magnitudes, dates, effects

2.  Minor extinctions

3.  Recovery from extinctions

 

IV.  Major principles and patterns of ecosystem history

A.  Dominance and the rise in metabolic rates

B.  The role of disturbance

C.  Increased control by organisms over energy and material resources through greater recycling and ecosystem expansion

D.  The role of incumbency

E.  Contingency and predictability

F.  Increased rate of change through time:  decreased stability yet less disturbance

 

V.  The human-dominated biosphere

A.  Human origins:  we as a superspecies; when, where, and under what circumstances humans arose and evolved

B.  The human impact on world ecosystems

C.  The future:  incumbency, extinction, invasion, responsiveness of ecosystems, recycling, opportunities for evolution, productivity

D.  The lessons of history: limitations and opportunities