Sustainability and Changing Paradigms

Sustainability and Changing Paradigms

Lesson Outcomes define sustainability define paradigm describe an example to illustrate a paradigm shift examine the attitudes and practices of our forefathers in terms of the

taking of natural resources in relation to the concept of sustainability discuss how attitudes toward our forests have changed with respect to

commercial usage, residential usage, and replanting programs

discuss the conditions necessary for a sustainable fishery

The way that humans view the world is known as a paradigm.

Changes in paradigms are known as paradigm shifts.

Sustainability

The modern paradigm views the Earth as a sustainable system provided that renewable resources are not used at a faster rate than they are replaced or recycled.

The term sustainability means that the system can meet the needs not only of our present human population, but also those of the future.

Questions to think about… How would you describe your own views about the taking of natural resources? Can man continue to exploit the Earth's resources as if they were unlimited? Has the overall focus shifted to environmental issues and concerns? Why are we shifting to a different paradigm? How does loss of habitat (habitat destruction) affect biodiversity? What responsibility do we have regarding the extinction or endangerment of

species? What responsibility must we take regarding pollution - water, air, and soil? How does the practice of clear-cut logging affect the environment? Is clear-cutting of forests a sustainable practice? We place value on products made as a result of the taking of natural resources

but do we consider the value of the original resource and the long term cost of its destruction?

Do we care about the problems listed above? What can we do as individuals to change?

Not that long ago (early 1900s), most people believed that natural resources were limitless.

Renewable resources are those resources that will continue to get replaced if not overused or abused, and that are in such supply that they will last for an extremely long time.

Examples: fishery, forest, wildlife, water, solar energy and wind.

Renewable Resources

Nonrenewable resources

Nonrenewable resources are those that are in limited supply and can be completely used up of action is not taken to protect them.

Examples: fossil fuels (oil and gas), minerals and soils.

Explain why each of the following is or is not a sustainable practice.

Taking oil from the grand banks of Newfoundland.

Establishing an open pit diamond mine in the far north (tundra).

Replanting trees in a forest clear-cut. Catching more fish each year than are

reproduced.

Changes in our paradigms about our forest.

If trees were cut down to build a ship, a home, or to use as fuel, little or no thought was given to it. The forest would simply grow new trees to replace those taken.

The early foresters used simple tools including an axe and a saw. A typical forest worker could cut and stack about two cords (a cord is defined as a pile of wood 4 feet high x 4 feet wide x 8 feet long) of wood per day.

Today’s Forestry Industry… Technology has changed and the equipment is

available which can cut 2 cords of wood in just a few minutes rather than a day.

With this change in technology, can our forests now be considered limitless?

What will happen to our forests if we cut them down at a rate faster than they can grow back?

What effect does clear-cutting have on the forest ecosystem?

Changes in our Paradigms

about our fishery Fish would be taken from the seas with no thought about the

number that remained. It was believed that man could never take all the fish that existed within the lakes and oceans because there were so many fish and relatively so few fisherman.

The technology used by the inshore fisherman included the use of an open boat known as a dory and a single jigger attached to a length of line. The jigger would then be brought up just off the bottom and jigged up and down until it struck a cod. This cycle was repeated until the boat was full.

Today…

Modern technology has changed to include the use of factory ships which make use of drift nets more than 5 km long, and electronic equipment designed to detect the location of the fish.

Fish are caught by the metric ton rather than as individual fish. The number of fish taken as a result of the use of modern technology has destroyed the fish stocks to the point that the Atlantic Canada fishery has been shut down to allow the recovery of the fish stocks.

Was the change in fishing technology sustainable? Can we manage a sustainable fishery in the future?

Messages http://www.youtube.com/watch?

v=6FsAw8HeSvU Mother earth http://www.youtube.com/watch?

v=tD5XUZ90e5s&feature=related

Introduction to Ecology

Lesson outcomes define ecology and ecosystem distinguish between biotic factors and abiotic factors and

describe examples to illustrate each explain how abiotic factors affect the sustainability of the

ecosystem describe examples to illustrate biotic interactions describe ways that organisms respond to changes in

environmental conditions describe symbiotic relationships including: mutualism,

commensalism, parasitism, and predation describe trophic structure in terms of food chains and food webs explain how biotic and abiotic factors affect ecological

interactions and the distribution of organisms

Ecology is the scientific study of the interactions of organisms and their environment.

Interactions of organisms and their environment refers to the way the organism affects the environment as well as how the environment affects the organism.

An Ecosystem is a community of organisms and the physical environment in which it lives.

Each of the following concepts describes the organisms within their environment

Abiotic Factors Biotic Factors Symbiotic Relationships Trophic Structure Herbivore, Carnivore, Omnivore and

Saprobes

Abiotic Factors Abiotic factors are the nonliving factors

which affect life in any ecosystem. Some abiotic factors are described below:

Space Temperature Oxygen Sunlight Water Inorganic and Organic Soil Nutrients

Biotic Factors Biotic factors refer to the living

environment and include all other organisms that interact with the individual both of the same species and all other species.

Biotic factors also includes: Detritus (decomposing animals and plants) and Disease Predator/prey interaction Competition Symbiotic relationships

Symbiotic relationships Symbiotic relationships are biotic

relationships in which two different organisms live in close association with each other to the benefit of at least one. There are five types of symbiotic relationships including: mutualism, commensalism, parasitism, parisitoidism. and predation.

Symbiotic relationships

Mutualism is the type of symbiosis resulting in mutual benefit to both of the organisms in the relationship.

An example of this would be the relationship between the algae and fungus of lichens. The fungi penetrate the roots of the plants and make soil nitrogen available to the plant, receiving carbohydrates in return. This allows them to live in an environment in which neither could survive alone.

Symbiotic relationships

Commensalism is a relationship in which one organism benefits from the relationship but the other organism seems to neither be harmed nor benefited.

One example to illustrate commensalism is the beaver and the fish. A beaver builds a dam to regulate water level which helps the beaver survive winter. The fish benefit from the beaver, but the beaver is neither harmed nor gains benefit from the fish.

Another example of commensalism is the relationship between

trees and nesting birds.

Symbiotic relationships

Parasitism is a symbiotic relationship in which one organism benefits and the other is harmed. The organism that benefits is called the parasite, the organism that is harmed is called the host.

An example would be the tapeworm. They live in the digestive tracts of various organisms, while there they are provided with nutrient and an environment in which to grow and reproduce. However, the host is harmed by the presence of the tapeworm.

Symbiotic relationships Predation is where the interaction is beneficial to

one species and detrimental to the other. This is not always considered a symbiotic relationship, although it is quite similar to parasitism, except for the degree of harm to the host or prey. With predation, the prey is killed.

An example of predation is when a lion kills a zebra and eats it as its source of food.

Trophic Structure

Trophic structure refers to the feeding relationships within the ecosystem. These feeding relationships are generally divided into five trophic levels based on their source of nutrition

Trophic StructureFive trophic levels based on their source

of nutrition primary producers primary consumers secondary consumers tertiary consumers decomposers (also known as

detritivores).

Trophic Structure Feeding relationships are generally viewed as a food web

consisting of all the possible food chains that exist within the

ecosystem.

Trophic Structure Producers or autotrophs are organisms,

such as green plants, that produce their own food. They make organic compounds (food such as sugar) from inorganic compounds (carbon dioxide and water) by photosynthesis.

Consumers or  heterotrophs are organisms that obtain nutrients from other organisms. They cannot synthesize their own food so they must obtain it ready made.

Trophic Structure Decomposers are organisms of decay.

These are also called saprobes. They are generally fungi or bacteria that break down the complex compounds in the remains of dead animals and plants, producing simple substances that can be used again by the producers.

Trophic Structure Herbivores are animals that feed only on plants.

Rabbits, cattle, horses, sheep and deer are all herbivores. Carnivores are animals that feed on other

animals. Some carnivores may be predators (such as lions, hawks, and wolves who attack and kill their prey and feed on their bodies) and some may be scavengers (they feed on dead animals that they find).

Omnivores are animals that feed on both plants and animals. Examples of omnivores are humans and bears.

Saprobes are organisms that get nutrients by breaking down the remains of dead plants and animals, or their wastes. Examples of saprobes are bacteria and

fungi.

1. Which branch of biology studies the interactions among organisms and their environment? a. meteorologyb. ecologyc. botanyd. genetics

2. Which is an example of a biotic factor that affects the size of a population in a specific ecosystem?a. average temperatureb. amount and kinds of soil mineralsc. concentration of oxygend. number and kinds of predators

3. Which is the best example of a biotic interaction?a. Plants grow more slowly in winter than in summer.b. Fish move to deeper, cooler water during summer.c. Sea birds often compete for nesting space. d. Wind often causes trees to grow very short.

4. Fish often live in a beaver pond. What relationship is illustrated by this example? a. mutualismb. commensalismc. parasitismd. predation

5. Which term refers to an animal, such as a bear, that eats both plant and animal? a. autotroph b. primary consumer c. herbivore d. omnivore

6. Which is required by any terrestrial ecosystem? a. a producerb. a tertiary consumerc. at least five trophic levelsd. a fourth level carnivore

1. Which branch of biology studies the interactions among organisms and their environment?

a. meteorologyb. ecologyc. botanyd. genetics

2. Which is an example of a biotic factor that affects the size of a population in a specific ecosystem?

a. average temperatureb. amount and kinds of soil mineralsc. concentration of oxygend. number and kinds of predators

3. Which is the best example of a biotic interaction?

a. Plants grow more slowly in winter than in summer.b. Fish move to deeper, cooler water during summer.c. Sea birds often compete for nesting space. d. Wind often causes trees to grow very short.

4. Fish often live in a beaver pond. What relationship is illustrated by this example?

a. mutualismb. commensalismc. parasitismd. predation

5. Which term refers to an animal, such as a bear, that eats both plant and animal?

a. autotroph b. primary consumer c. herbivore d. omnivore

6. Which is required by any terrestrial ecosystem?

a. a producerb. a tertiary consumerc. at least five trophic levelsd. a fourth level carnivore

Read 1.5 "Ecology" on pages 22-23. Answer questions 1-6 from "Understanding Concepts" on page 23.

 Energy flow through an

ecosystem The vast majority of life on Earth

depends on sunlight as its source of energy. Of all the radiant energy that reaches the earth, some of it penetrates the earth's atmosphere to the Earth's surface, but only a small quantity is used to drive the process of photosynthesis.

About 0.023% of the energy that reaches the Earth is used in photosynthesis, yet this energy is sufficient to drive nearly all life on Earth!

The actual amount of energy that reaches the surface of the Earth is affected by the albedo effect of clouds and dust particles in the atmosphere.

Albedo is a measure of the amount of light reflected from an object.

Albedo is normally expressed as a decimal value representing the percentage of light reflected.

For example, clouds have an average albedo about .27 so about 27% of the suns energy is normally reflected by clouds back to space. On a clear day, more light

would be able to penetrate to the Earths surface and as a result a greater amount of photosynthesis should occur.

Photosynthesis, a biological process, uses the energy of sunlight to manufacture sugar, which serves as the universal food for life. Oxygen produced as a product of photosynthesis is released into the environment

6CO2 + 6H2O + sunlight energy → C6H12O6 + 6O2

  where CO2 represents carbon dioxide H2O represents water C6H12O6 represents the sugar molecules

(carbohydrate) and O2 represents oxygen As you can see from the formula, the energy that had originally come

from the sunlight is transferred to the molecules of sugar, (C6H12O6 ),

The sugar serves as the source of energy for nearly all life on Earth.

The energy stored in the sugar is passed from the plants to other organisms when the plants are consumed as food.

This passage of food from producer to various consumers in turn is known as a food chain.

If the community has a great deal of biodiversity, there will be several organisms that can feed on more than one type of food resource

as a result there would be several possible food chains. which together make up a food web.

Each step in the food chain is called a trophic level. Corn → Mouse → Snake → Hawk

energy flow always begins with a producer. Producers are also known as autotrophs. The mouse, snake, and hawk are consumers.

Consumers are called heterotrophs because they can not make their own food.

The final consumers in any food chain/web are the decomposers.

Corn → Mouse → Snake → Hawk → Decomposers

 

To release the energy stored in the sugar, organisms carry out a metabolic process known as cellular respiration.

The process of cellular respiration does transfer energy from the food to the organism for carrying life processes, but also releases heat which can not be used any further.

The transfer of energy from one trophic level to the next is never 100% efficient since each organism must utilize some of the energy to support its own existence.

The idea that each higher trophic level has less energy available to it is known as the pyramid of energy.

The Pyramid of Energy. Energy is not recycled. As the food is passed through the food web,

most of the energy is lost. In general terms, about 10% of the energy

stored in one trophic level (such as producers) is actually transferred to the next trophic level (for example the herbivores)

Eventually there is so little energy remaining in the top trophic level that no higher trophic level can be supported. This is why there are so few if any fourth order consumers in an ecosystem.

The figure below represents the 10% rule for energy transfer.

Pyramids of Biomass and Number Since the amount of water present within the tissues of different

organisms varies, biologists use the dry mass of the organism for comparison since it is believed that dry mass more closely reflects the actual amount of "living matter" in the organism.

The dry mass is known as biomass. The availability of energy will also affect the number of organisms and the mass of the organisms at each trophic level.

The pyramid of biomass is a graphical representation of the total biomass of all the members of each trophic level. Generally the pyramid of biomass has the same shape as the pyramid of energy.

In a grassland environment, 10,000 kg of grass and other producers (dry mass) should support about 1,000 kg (dry mass) of grasshopper

and other plant eating insects.

The pyramid of number is the third type of graphical representation used by biologists to study ecosystems. The pyramid of number is often similar in shape to the pyramid of energy or biomass, but there are exceptions.

Consider a single spruce tree in a boreal forest (biomass = 100 kg) which is infested by 100,000 spruce bud worms (total biomass = 10 kg), which are in turn eaten by 5 insect eating birds (total biomass = 1 kg). The pyramid of biomass would appear normal (base representing 100 kg, middle piece representing 10 kg, and a top piece representing 1 kg). The pyramid of number for this example will not look normal. The pyramid of number would have a very small base representing the producer (1 tree), a very large herbivore level (100,000 spruce bud

worms), followed on top by a small predator level (5 birds).

Some species in the ecosystem function as a keystone species.

A keystone species is one considered so important to the stability of the ecosystem, that if there was a decline in that species, the community would not be able to maintain its stability and may even collapse.

E.g: Sea Otter