Communities & Ecosystems


Video Clips

Levels of Biological Studies (7.014, Spring 2005)

Video RealVideo®
8:05 minutes (15:27 - 23:32)

Description and examples of biological study - Biosphere, ecosystems, populations, organisms, and cells.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Overview of Ecology (7.014, Spring 2005)

Video RealVideo®
7:59 minutes (2:48 - 10:47)

Overview, history, and levels of living systems.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Emergent Properties (7.014, Spring 2005)

Video RealVideo®
8:33 minutes (16:45 - 25:18)

Definition and complexity theory. Feeback between organism and environment. Need to study system as a whole with environmental influences. "Natural" state and man-made influences to our biosphere.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Organism/Environment Interaction (7.014, Spring 2005)

Video RealVideo®
15:21 minutes (25:18 - 40:39)

Two-way relationship between the individual and the environment. Examples: Microbes and plants, nitrogen fixation, the carbon cycle, and fossil fuel.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Molecular Ecology (7.014, Spring 2005)

Video RealVideo®
5:00 minutes (40:39 - 45:39)

Study of biosphere as a network of genes. Example: Ocean and microbial life.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Primary Productivity (7.014, Spring 2005)

Video RealVideo®
10:32 minutes (1:43 - 12:15)

Collective photosynthesis. Types and habitats of primary photosynthesizers. Definitions and examples: Biomass, gross primary productivity, respiration rate, net primary productivity, mean residence time, and fractional turnover.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Photosynthesis
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World Net Productivity (7.014, Spring 2005)

Video RealVideo®
6:07 minutes (13:45 - 19:52)

Net primary productive and turnover time in different land and marine ecosystems.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Productivity
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Food Web and Energy Transfers (7.014, Spring 2005)

Video RealVideo®
13:40 minutes (19:52 - 33:32)

Flow of energy through an organism within the food web. Comparisons of exploitation, assimilation, and production efficiencies of different organisms Connection and relationship between grazing, microbial, and detrivore food webs.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Productivity and definitions
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Comparison of Ecosystems (7.014, Spring 2005)

Video RealVideo®
8:18 minutes (33:32 - 41:50)

Open ocean versus tropical forest ecosystems. Average ecological efficiency and number of tropic levels in each ecosystem.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Productivity
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Terrestrial Ecosystems (7.014, Spring 2005)

Video RealVideo®
4:00 minutes (2:15 - 6:15)

Light, water, temperature correlate direct to productivity in terrestrial ecosystems.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Previous sections on productivity
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Biosynthesis and Regeneration (7.014, Spring 2005)

Video RealVideo®
7:55 minutes (6:15 - 14:10)

Conversion to organic forms, recycling, minerals and rocks. Comparison of tropical rain forests and temperate forests in terms of biomass and soil nutrient.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Water Column (7.014, Spring 2005)

Video RealVideo®
6:32 minutes (21:18 - 27:50)

Light, temperature, and nutrients as functions of water depth. Light, water, and nutrients affect marine productivity. Nutrients are most dense in the bottom due to recycling.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Lake Ecosystems and Mixing (7.014, Spring 2005)

Video RealVideo®
3:13 minutes (27:50 - 31:03)

Need to bring up nutrients from the bottom to the light at the top in order to utilize the nutrients. Thermocline in the lake and seasonal nutrient mixing.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Ocean Nutrient Renewal (7.014, Spring 2005)

Video RealVideo®
10:00 minutes (31:03 - 41:03)

Definition and explanation of four types of mixing: Episodic mixing, costal upwelling, equatorial upwelling, and oceanic "conveyer belt".

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Lake ecosystems and mixing
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Importance of Nutrients (7.014, Spring 2005)

Video RealVideo®
6:16 minutes (41:03 - 47:19)

"Law of minimum." Growth of plants can be limited by nutrients in lowest supply relative to requirements. Example: Carbon/Nitrogen/Phosphorus ratio.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Biogeochemical Cycles - Overview (7.014, Spring 2005)

Video RealVideo®
4:22 minutes (3:53 - 8:15)

Interconnected biogeochemical cycles. Definition of related terms. Flux, steady state and non-steady state effects. Solar energy as the primary source that drives the various cycles.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Productivity
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Geological Cycle (7.014, Spring 2005)

Video RealVideo®
3:50 minutes (8:15 - 12:05)

Cycle participants and length. Solar and geothermal energies as input. Cycle includes various rocks and soils.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Water Cycle (7.014, Spring 2005)

Video RealVideo®
5:16 minutes (12:05 - 17:21)

Reservoirs, fluxes, and balances within the cycle. Residence time of water in reservoirs.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Global Phosphorous Cycle (7.014, Spring 2005)

Video RealVideo®
4:36 minutes (17:21 - 21:57)

Sedimentary cycle without atmospheric component. One way flow influenced by human activities. Reservoirs, fluxes, balances, and participants of the cycle.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Global Nitrogen Cycle (7.014, Spring 2005)

Video RealVideo®
10:21 minutes (21:57 - 32:18)

Transformations between various nitrogenous components using redox chemistry-nitrification, denitrification, nitrogen fixation, and ammonification. Reservoirs, fluxes, imbalanced cycle, and human influences.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Redox chemistry; aerobic and anaerobic conditions
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Global Carbon Cycle (7.014, Spring 2005)

Video RealVideo®
4:40 minutes (35:31 - 40:11)

Reservoirs, fluxes, and imbalances that result in carbon dioxide annual increase in the atmosphere.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Community Ecology (7.014, Spring 2005)

Video RealVideo®
4:23 minutes (0:39 - 5:02)

Definition, characteristics, and effects on the environment.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Species Interactions (7.014, Spring 2005)

Video RealVideo®
5:32 minutes (5:02 - 10:34)

Definition and implications of Darwinian fitness, Adaptation, and Competition. Possible relationships between two organisms with respect to fitness.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Competition (7.014, Spring 2005)

Video RealVideo®
3:52 minutes (10:34 - 14:26)

Intraspecific and interspecific competition.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Ecological Niche (7.014, Spring 2005)

Video RealVideo®
6:34 minutes (14:26 - 21:00)

Definition, niche overlap, and competition.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Competition Experiment (7.014, Spring 2005)

Video RealVideo®
7:03 minutes (21:00 - 28:03)

Gause's experiment of growing competing organisms in simple, controlled environment. Developed logistic equations to predict growth of one population taken into consideration size of the other population.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Logistic equations
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Video RealVideo®
10:13 minutes (28:03 - 38:16)

Case study of introduction of zebra mussel as an invasive species. Case study on growth of two species of barnacles.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Competition
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Biogeochemistry (7.014, Spring 2005)

Video RealVideo®
5:49 minutes (10:47 - 16:36)

Definition, scale, and studies. Earth as a biosphere.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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System for Bacteria (7.014, Spring 2005)

Video RealVideo®
5:16 minutes (21:58 - 27:14)

Environment and conditions of deep sea volcano for chemosynthetic bacteria.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Chemosynthesis
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Character Displacement (7.014, Spring 2005)

Video RealVideo®
6:12 minutes (38:16 - 44:28)

Changes in physical characteristics that lead to competitive co-existence. Example: Beak depth of species on the same island.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Video RealVideo®
8:58 minutes (3:01 - 11:59)

Growth, changes, and immigration of species inhabiting different islands.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Predation (7.014, Spring 2005)

Video RealVideo®
16:53 minutes (11:59 - 28:52)

Predation as a force of evolution. Prey and predator logistic equations that are dependent on each other's densities, creating an oscillatory system. Example: Snowshoe hare and cats; prey and predator mites.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Predation and Community Structure (7.014, Spring 2005)

Video RealVideo®
17:44 minutes (28:52 - 46:36)

John Wart's experiment that demonstrated that predation affects community structure within a niche. Predators and prey that drive evolution of both populations. Example: Industrial melanism.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: Predation
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Lecture Notes

Productivity (7.014, Spring 2005)

Document PDF
Page 1

Definition and calculation for primary productivity, gross and net productivity, mean residence time, and fractional turnover.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Document PDF
Page 2

Definition and calculation for exploitation, assimilation, and production efficiencies at each trophic level and overall ecological efficiency.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Practice Problems

Ecosystems (7.014, Spring 2005)

Document PDF
Problem 2 (page 2)

Use characteristics and genes expressed in two ecotypes to determine their environment in the water.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Food Web - Example (7.014, Spring 2005)

Document PDF
Problem 3 (page 3)

Productivities and efficiencies in a food web. Determine the food source that gives the highest ecological efficiency.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Document PDF
All Problems (page 1)

Components and energy transfer of a food web involving plants, herbivores, and carnivores. Example of estimated transfers and efficiencies.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Communities (7.014, Spring 2005)

Document PDF
All Problems (page 1)

Example demonstrating predator-prey relationship as well as food source and consumption. Comparison of top-down and bottom-up models.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Exam Questions

Document PDF
Problem 2 (page 3)

Efficiencies and energy transfers in a food web. Changes in parameters created by addition of new organisms.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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Document PDF
Problem 2b (page 4)

Niche for individual species and relationships between two species.

Instructors: Prof. Penny Chisholm, Prof. Graham Walker, Dr. Julia Khodor, Dr. Michelle Mischke
Prior Knowledge: None
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