St/Est 404 the Living World

ST/EST 404 THE LIVING WORLD

CHAPTER 10 NOTES

CHAPTER 10

Ecosystems

(pp. 316 - 347)

1 What is an ecosystem?

After the individual, the population and the community, the fourth level of ecological organization is the ______.

1.1 INTERACTIONS WITHIN AN ECOSYSTEM: TROPHIC RELATIONSHIPS

Ø Trophic relationships are the ______connections among the ______organisms in an ecosystem.

· Trophic relationships are often represented by a ______.

· The position of each organism in a chain corresponds to its ______.

· Food chains contain the following trophic levels:

· ______

Example:

______

(grass) (woodland vole) (milk snake) (owl)

______

(sow bugs) (microorganisms) (earth worms) (fungi)

PRODUCERS

Organisms like plants, ______and certain ______can transform ______matter into organic matter.

Category / Description / Examples
Inorganic matter / Matter that is ______necessarily produced by living organisms. / Water, ______
Organic matter / Matter that enters into the composition of ______organisms and that is usually ______by them / Proteins, ______,
______

· Autotrophs (A.K.A ______) are at the bottom of the food chain because they introduce ______into the ecosystem.

· They use ______, ______, carbon dioxide and soil nutrients to produce organic matter.

· The process by which they do this is called ______.

CONSUMERS

Heterotrophs (A.K.A ______) are living organisms that CANNOT produce food for themselves. They obtain the ______they need by eating ______living organisms or their products.

Consumers can be divided into different types.

1. ______or first order consumers feed on ______or their seeds. Examples: ______, granivores (seed-eaters) and frugivores (fruit-eaters)

2. Consumers of the second, third and fourth orders ______species of the respective ______order. Species in the second order or higher are usually ______.

F NOTE: In different food chains, an animal’s order can be ______.

3. ______are consumers of several orders at once.

DECOMPOSERS

· Decomposers are connected to ______the trophic levels.

· They feed on ______(dead organic matter) breaking it down into ______matter.

A trophic network (or food ______) is a representation of the many trophic ______that exist in an ecosystem.

http://classes.dma.ucla.edu/Winter06/161B/projects/tonyau/ps2/1/images/FoodWeb.JPG

1.2 Ecosystem Dynamics

MATERIAL FLOW AND CHEMICAL RECYCLING

Matter cannot be ______or ______(Law of Conservation of Mass).

Producers are constantly changing inorganic matter from the environment into ______matter.

What prevents all the inorganic matter from being used up by the producers?

______are continually breaking down the ______matter in the detritus they feed on, producing the ______matter that plants need.

IT’S THE CIRCLE/CYCLE OF LIFE!J

Matter passes from one ______to another, but it remains in ______in the ecosystem.

ENERGY FLOW

· ______is the primary source of energy in an ecosystem.

· Producers (autotrophs) transform part of that ______energy into ______energy which is then passed on to ______.

· At every trophic level, organisms obtain energy from the ______they eat and store it in their tissues.

· As energy passes from one ______level to the next, a large part is ______in the form of ______and ______.

· Unlike matter, energy is ______recycled, so ecosystems must receive a continual supply of new energy from the ______.

ENVIRONMENTAL EXTRA (p.323) What is vermicomposting and why is it growing in popularity?

______

1.3 PRIMARY PRODUCTIVITY IN ECOSYSTEMS

One of the most important parameters in the study of ecosystems is the mass of new organic matter they produce.

Ø ______is the total mass of all organic matter (plant and animal) in an ecosystem at any given time.

Ø The Primary Productivity in an ecosystem is the amount of new ______generated by its ______.

The more new organic matter created in an ecosystem, the ______the capacity of the ecosystem to supply energy to its organisms.

FACTORS AFFECTING PRIMARY PRODUCTIVITY OF AN ECOSYSTEM

· Amount of ______(sun is necessary for ______)

· Amount of ______available

· Access to essential ______for producers (esp: ______, ______, ______and ______)

· ______(some weather conditions ______the growth of producers while others do not)

PHYTOPLANKTON UNDER THREAT (p. 325) – Why is a drop in phytoplankton concentration a cause for concern? ______

______

2 Disturbances

Ø A disturbance is an event that ______an ecosystem. It can lead to the ______of an organism and alter the availability of ______.

· Disturbances can be of different ______. (Examples: snowstorms, sandstorms, ______or ______eruptions)

· Disturbances may vary in ______. (Example: some rivers flood every spring while other rivers flood only occasionally.)

· Disturbances can be more or less ______in nature. (Example: an ice storm will cause less damage if it lasts only a few ______than if it lasts several ______.)

2.1 NATURAL DISTURBANCES

They are triggered by ______phenomena rather than by ______.

Examples of natural disturbances include the following:

ST/EST 404 THE LIVING WORLD

CHAPTER 10 NOTES

· ______

ST/EST 404 THE LIVING WORLD

CHAPTER 10 NOTES

2.2 HUMAN DISTURBANCES

Humans remain the main source of environmental disturbances on Earth. These activities that damage ecosystems may be individual acts like ______to large-scale projects, like ______operations, ______spills at sea, and ______.

2.3 ECOLOGICAL SUCCESSION

Following a disturbance, an ecosystem will undergo a series of gradual ______, which may be spread out over ______of years. Any alteration in an ecosystem leads to change.

END OF CHAPTER 10 ST NOTES

2.4 ECOLOGICAL FOOTPRINTS (EST ONLY)

Many ______on Earth are disturbed by humans because we need to ______part of the world’s resources to survive.

Equation for calculating the ecological footprint of a population:

Ecological Land and water Land and water used Land and water

footprint of = occupied by + to produce goods + to dispose of the

a population the population and services for population’s waste

the population

With this equation we can calculate the impact of human activities on ecosystems.

Resources available for development in the Earth’s ecosystems correspond to the Ecological ______.

In 2003, the Earth’s carrying capacity was ______hectares per person.

· If the ecological footprint of each human was equal to this amount, it would mean that all the Earth’s surface was under ______.

· If the footprint were greater, it would mean that the Earth was not ______enough to meet our needs

· If the footprint were smaller, the Earth would be able to ______both present human needs and those of future______, and even those of populations of other ______.

Canada’s average ecological footprint is ______hectares per person - ______times greater than the Earth’s carrying capacity. This means that if all humans were as avid consumers as Canadians are the Earth’s population would need ______planets like its own just to meet all its needs! This is a very scary statistic when you consider that there are 8 countries whose ecological footprint is larger than ours!!!! Check out the web site listed below.

http://www.nationmaster.com/graph/env_eco_foo-environment-ecological-footprint

3 Ecotoxicology (EST ONLY)

Humans disturb the world’s ecosystems by ______them with substances that do not occur there naturally or by significantly increasing ______of substances already present.

3.1 CONTAMINANTS

Table 10.19: MAIN CLASSES OF CONTAMINANTS

CLASS OF CONTAMINANTS / EXAMPLES
Inorganic contaminants / Lead, ______, nitrogen oxides,______, ______
Insecticides, pesticides, polychlorinated biphenyls (PCBs), benzene
Viruses and harmful bacteria
Radioactive contaminants / ______, ______, ______

A contaminant is said to be toxic when it ______an organism.

Toxicity depends on three factors:

______. The more concentrated the contaminant, the ______the risk that it is toxic. Ex. In Quebec, concentration of lead (Pb) in drinking water cannot exceed 0.01 ppm.

Type of ______it comes in contact with. Certain contaminants are toxic to some organisms but not to ______. Ex. Certain ______are toxic only to broad-leaved weeds.

The length of ______. Generally, the longer the exposure, the ______the risk of toxicity.

TOXICITY THRESHOLDS

Examples:

· World Health Organization sets average toxicity threshold of SO2 for plants at 30 mg/m3.

· Microcystins released into water by cyanobacteria have a toxicity threshold of ______for humans.

Toxic effects vary but can include red ______on skin or ______.

F Lethal ______ is the amount of contaminant necessary, in a ______dose, to cause organisms death.

F LD50 is the dose that causes death among ______% of individuals.

3.2 THE BIOACCUMULATION AND BIOCONCENTRATION OF CONTAMINANTS

Many contaminants that result from human activities ______natural degradation and can ______ecosystems for years.

Examples of pollutants which can be absorbed by living organisms include heavy ______, ______(a substance with insulating properties), and ______(a powerful insecticide).

BIOCONCENTRATION (or ______) is a phenomenon by which the ______of a contaminant in the tissues of living organisms tends to ______with each trophic level.

4 Biotechnology to the rescue (EST ONLY)

Discharge of contaminants from our ______, ______and ______waste have caused many of the world’s environment problems and often it is not possible to simply remove the ______water and ______from a polluted site. Solutions in ______are used to counteract certain environmental problems.

4.1 DECONTAMINATING SOIL THROUGH POLLUTANT BIODEGRADATION

Ø Biodegradation is the breaking down of organic matter into inorganic matter by ______.

Ø Bioremediation is a ______for cleaning up a ______site, using micro-organisms that ______contaminants.

· Fertilizer sprayed onto an oil-soaked beach can ______the growth of microorganisms that degrade the ______.

· The fungus, Phanerochaete chrysosporium, can chew up some of the long-lasting ______resins that clog landfill sites.

4.2 PHYTOREMEDIATION

· Plants can also be used to ______sites by absorbing contaminants in ______, ______or ______. The plants can then be harvested so that the contaminants can be ______and ______.

· ______is a biotechnology that uses plants or algae to eliminate contaminants from a site.

· Cabbages can be used to remove ______from the soil.

4.3 WASTEWATER TREATMENT

Methods to limit the ______of pollutants also exist and are applied mainly to treating ______.

Wastewater is water that is discharged after ______or ______use and that is polluted as a result of human activities.

Undesirable elements in wastewater include

· Sand and other ______particles

· ______(microorganisms that can cause disease)

· Decomposing ______

· Nutrients that stimulate excessive growth of ______, ______and aquatic plants

· ______

There are two main methods to treat and clean wastewater before returning it to the environment.

1. ______tanks

2. ______plants

1. SEPTIC TANK

http://www.captainwater.com/septictank-picture.jpg

HOW IT WORKS

1. ______from the house is drained into a container – the ______.

2. Solid waste ______at the bottom of the tank and forms ______.

3. The ______is occasionally collected by specialized companies, which treat it to make it ______to the environment.

4. The ______part of the wastewater can drain out of the ______tank into the surrounding land (______) where ______decompose it.

2. WASTEWATER TREATMENT PLANT

http://blog.pennlive.com/pennsyltucky/2008/07/Waste70908.jpg

PRIMARY OR PHYSICAL TREATMENT

1. Wastewater passes through a screen to remove ______piece of debris (plastic bags, rags, etc.)

2. ______and ______is removed in a degritter.

3. ______sedimentation: Heavy ______matter collects in a ______tank where it forms ______which is then emptied out of the tank.

SECONDARY OR BIOLOGICAL TREATMENT

4. Waste water is transferred into another tank where it is mixed with ______and a lot of air which eliminates contaminants.

5. ______sedimentation: Remaining solids fall to the ______of the secondary settling tank.

DISINFECTION

6. Water is treated with ______compounds or ______rays to destroy disease-causing (pathogenic) microorganisms.

7. The water is then discharged back into the river or lake from whence it came.

END OF CHAPTER 10 EST NOTES