CIV220 Urban Engineering Ecology
Bagley L3: Fundamentals of Ecosystems – Mass:
A self-sustaining biological system that consists of individual
organisms, populations of organisms and communities of populations
living together and interacting with each other and the surrounding
• Mass and energy are conserved in ecosystems
Bagley L4: Fundamentals of Ecosystems – Energy:
• 2 Law of Thermodynamics
The amount of useful energy in a system decreases with every energy
transfer, OR for every spontaneous reaction that occurs, entropy
• Energy flows through ecosystems and it is the flow of energy that
drives the cycling of mass in ecosystems.
Bagley L6: Energy Flow through Ecosystems:
Organisms that can convert light energy to chemical bond energy and
convert carbon dioxide and other inorganic nutrients to organic
Organisms that can only obtain energy for life from chemical bond
Bagley L5: Food Chains & Bioaccumulation:
• Food Chain Movement of energy from one trophic level to another.
Organisms that eat detritus (waste material), e.g.; vultures, fungi,
The effect of toxic compounds. There are two types of toxicity.
o Acute Toxicity
Toxicity is manifested rapidly, or acutely. Responses include
disease, loss of reproductive capability and sever mutations. It
is caused by exposure to highly toxic compounds and large
doses of less toxic compounds over a short period of time.
o Chronic Toxicity
Toxicity is manifested slowly, or chronically. It is caused by
long-term exposure to small concentrations of toxicants. An
example is the toxicity caused by carcinogens.
The concentrating of chemicals in species higher up in the food
chains. Materials that bioaccumulate are pesticides, heavy metals,
PCBs, and fat-soluble chemicals.
• Global Distillation
The spreading of harmful chemicals through a cycle of evaporation,
atmospheric circulation and, eventually, condensation in sub-zero
temperatures. This processes has resulted in colder areas like the poles
becoming “sinks” for these compounds.
Bagley L12: Cells and Metabolism:
Self-contained biological unit that is capable of metabolism and
reproduction. Organisms are made up of cells, and can even be single-
• Cell Self-contained biological package of molecules capable of
metabolism. Three main components:
o Cell Membrane
o Genetic Material (inside nucleus)
The sum of all chemical reactions occurring in living cell.
• Cell Membrane
It is the boundary between the cell and the rest of the universe. It is
the cell’s system boundary. It is made up of a double layer of
phospholipids, which are large molecules that have hydrophilic and
hydrophobic ends. This double layer lines up in a manner so that the
hydrophilic ends are towards the outsides so as to allow for the
movement of particles in and out of the cell.
Membrane proteins also help facilitate the movement of constituents
across the membrane.
• Genetic Material
The chemical compounds that store information required by the cell.
It is deoxyribonucleic acid (DNA). It is a polymer made of
Everything else inside the cell that is not genetic material or any other
Polymers made of amino acids. Proteins perform several functions:
Form the principle components of hair, horns and spider webs.
o Energy and material storage
For example, egg components.
For example, haemoglobin carries oxygen.
o Cell Movement
For example, contractile proteins in muscle. o Chemical Catalysts
For example, enzymes. Catalysts are substances that increase
the rate of reactions under a given set of conditions, but are not
consumed the by the reaction.
• There are two types of metabolism:
The chemical reactions conducted to build cell components
(synthesis). For example, plants take carbon dioxide and water
and produce sugar, cellulose and many other plant products.
The chemical reactions conducted to generate energy and
electrons. Catabolic reactions
Provide energy to maintain cell activities such as
movement and cell repair.
Provide energy to be used to synthesize new compounds
Provide electrons to be used for synthesis.
A cell stores the energy form catabolism to use in anabolism.
D&M Ch.6: Functional Ecology and Succession:
• Plant CSR Theory
Three primary threats to the survival of primary producers:
Anything adversely affecting the ability to accumulate carbon
through photosynthesis, e.g.; shade reduces productivity; cold
Anything that damages or destroys the biomass of plants and
bacteria, either directly (e.g.; forest fire) or indirectly (e.g.;
unstable substrate scree slope).
Effects of other plants or bacteria in competitive foraging for
resources such as water, light, nutrients and space.
The overview of the CSR theory shows that:
o Low stress, low disturbance Competitors (C-strategists) o Low stress, high disturbance Disturbance Tolerators (R-
o High stress, low disturbance Stress Tolerators (S-strategists)
o High stress, high disturbance Uninhabitable
• r-K Model (Opportunist- Equilibrium)
According to this model, there are two types of survival strategies:
o r-strategists who are opportunists. Often small and rapidly
dispersed, and are adapted towards rapid reproduction.
o K-strategists are equilibrium species. Lower rate of
reproduction larger and better at competing for resources and
tend to live longer.
The shifting of one ecosystem to another over time. Primary
succession refers to the development of an ecosystem in an
environment that previously had no life, e.g. lava fields.
Colonization small number of highly stress-tolerant plants, total
biomass is low, soil lacking organic matter and nutrients.
Development Colonizing organisms modify the environment,
making it favourable for other organisms. Pioneer organisms are
eventually replaced by more competitive species.
Climax A diverse ecosystem is achieved that does not succeed to
Bagley L11: Ecosystem Types:
• 4 major groups:
lentic (standing water)
lotic (running water)
estuaries (mouth of a river where stream meets tide)
upwelling regions – upwelling occurs when deep, cool
waters are brought against a continental barrier and
forced to the surface, e.g.; coast of Peru in South
Saltwater ecosystems are affected by temperature, salinity,
pressure, winds and tides.
Bagley L23: Diversity and Stability:
• Ecological Diversity
Also known as species richness, it is the number of species in an
ecosystem or region. It is found by counting the number of species,
and increases as the area, length of time spent counting and total
number of organisms counted increases.
• Diversity Indices
There are two types of indices:
o Dominance Indices – gives more weight to common, or
dominant, species, e.g.; Simpson Dominance Index
o Information Statistics Indices, e.g.; Shannon-Weaver Index
• Keystone Species
A species that ensures the diversity of an ecosystem because of its
predation on and/or other interaction with a number of species. Bagley L14: Defining systems:
Group of organisms of the same species in a specific system.
A specified group of processes with clearly defined boundaries.
The physical, geographic place where organisms live.
Bagley L15: Population Growth and Death:
The condition when things do not change with time.
The condition when a system is at minimum free energy.
• Carrying Capacity
The maximum possible population for a given level of resources.
Bagley L17: Competition and Coexistence:
Organisms compete for limited resources in an environment. There
are two types:
Competition for resources between organisms of the same
Competition for resources between organisms of different
• Gause’s Principle
At equilibrium, two species with identical resource requirements
cannot occupy the same habitat.
Bagley L18: Mutualism: • Mutualism
Relationship between two species that benefits both.
Relationship between two species that benefits one but does not affect
• Obligate Mutualism
Mutualistic organisms are dependent on each other for survival. There
are two types:
o Non-symbiotic Mutualism
Mutualistic organisms live physically different lives.
o Symbiotic Mutualism
Mutualistic organisms live together in close physical
Bagley L19: Predator-Prey Dynamics I:
• There are 4 general predator-prey relationships:
animals eating plants.
animals eating other animals.
organisms sustaining themselves at the expense of other
organisms not necessarily in the form of eating.
subset of carnivory where animals eat other animals of the
Bagley L21: Habitat Fragmentation:
• Habitat Fragmentation
The breaking up of a larger continuous habitat into smaller,
discontinuous pieces or fragments.
A collection of smaller, physically separated populations of the same species. There are 4 types:
Individual populations are far enough to actually become
Individual populations are close enough to allow
Direction of recolonization between individual
populations is arbitrary.
Large core population is extinction resistant.
Satellite populations are smaller and may become extinct.
Colonization or recolonization occurs from core to
Version of classic type.
Recolonization is so rapid that no individual population
Is considered a metapopulation.
Another version of classic type.
Individual populations are not recolonized after they
become extinct because
• physical barriers between colonies cannot be
breached due to distance or other obstacles like
• Other colony populations are not productive
enough to allow migration out.
Bagley L7: Photosynthesis:
The process of converting light energy into chemical bond energy.
• Reduction Reaction
Atoms receive electrons. Occurs during the dark phase of photosynthesis and does not require light.
• Oxidation Reaction
Atoms lose electrons. Occurs during light phase of photosynthesis and
Bagley L8: Oxygen and Carbon Cycles:
• Oxygen Cycle
o Photosynthesis – separates oxygen from water.
o Respiration – biochemical oxidation of compounds to produce
energy. Converts oxygen back to water.
• Carbon Cycle
formation of methane, facilitated by methanogenic bacteria.
Bagley L9: Sulphur, Acid Rain and Global Warming:
• Acid Mine Drainage
When sulphide found in mine tailings is exposed to air, it is oxidized
to sulphuric acid, and can cause acid mine drainage.
• Sewer Crown Corrosion
The same phenomenon as acid mine drainage except found in sewers
as a result of sulphide in sewer gas.
Bagley L24: Concepts of Industrial Ecology:
• Industrial Ecology
An approach to the design of products and processes that evaluates
such activities through the dual perspective of product
competitiveness and environmental interactions.
• Life Cycle Analysis (LCA)
Examination of an entire life cycle of a product from raw material to
disposal. Consists of three stages: o Inventory Analysis
o Impact Analysis
o Improvement Analysis
• Inventory Analysis
This stage consists of conducting mass and energy balances for the
product over its entire life cycle. It is conducted as follows:
o Clearly identify the final product of interest.
o Identify all of the processes involved in producing this product
and the mass and energy requirements of production.
o Identify the mass and energy requirements of the product
throughout its life.
o Identify the ultimate fate of the product.
• Impact Analysis
o How can the environmental impact of a product be determined?
o How can different enviro