S Science 1206
Life Science – Sustainability of Ecosystems
Exploits Valley High
Version 1.0
Unit 1 – Life Science
Sustainability of Ecosystems
- Define sustainability
- Examine historical attitudes and practices in relation to those of sustainability.
- Define a paradigm and paradigm shift.
- Discuss how attitudes towards pesticides have changed
- Discuss how attitudes towards forests have changed with respect to commercial usage, residential usage and replanting programs.
- Define ecology and ecosystem.
- Explain how biotic and abiotic factors affect ecological interactions.
- Define abiotic factors (include space, temperature, oxygen, light, water, inorganic and organic soil nutrients)
- Define biotic factors (include decomposing animals, disease, predator/prey, competition, symbiosis).
- Define succession.
- Describe the factors that contribute to succession.
- Describe what is meant by the term climax community.
- Examine the flow of energy in ecosystems using the concept of pyramid of energy.
- Examine how energy availability affects the total mass of organisms in ecosystems and summarize this relationship in a pyramid of biomass.
- Define niche and relate it to habitat.
- Classify organisms as producer, consumer, autotroph, heterotroph, decomposer, herbivore, carnivore, omnivore, and saprobe.
- Define competition and explain how competition arises among organisms.
- Differentiate between interspecific and intraspecific competition.
- Describe the feeding relationships in terms of competition, food chains, and food webs.
- Demonstrate how the many interrelated food chains give a community its stability and identify the conditions required for a stable self sustaining ecosystem.
- Examine the use of pesticides over the course of human history.
- Describe the impact that DDT usage has had on bird populations
- Describe how continued DDT usage in third world countries is impacting bird populations
- Diagram the carbon cycle and describe the processes required to cycle from carbon reservoirs to the atmosphere.
- Describe the importance of oxygen to ecosystems.
- Describe the significance of global warming and eutrophication.
- Describe how humans have altered the C, O, and N cycles in ecosystems.
- Describe what is being done to negate human impact on these cycles
- Analyze the impact of external factors on the ecosystem biomes; include weather change, introduced species, pollution and industry/agriculture.
- Explain why ecosystems may respond differently to short-term stress and long-term change
– Describe the potential impact that a large scale logging project could have on a native species such as the pine martin
– Explain the impact that an abnormally dry summer could have on a bog ecosystem
– Describe how ecosystems are able to respond to changes and return to its previous state
- Describe how soil composition and fertility can be altered and how these changes could affect an ecosystem.
– Explain the role that fertilizers and irrigation practices have had on soil quality
– Describe the potential impact that overuse of fertilizers can have on ecosystems
- Relate the distribution of biomes within Canada to the impact of external factors.
- discuss how abiotic factors affect the distribution of organisms
– discuss the reasons for ecosystems that share similar abiotic features also sharing similar animal life.
- Describe how Canadian research projects in environmental science and technology are funded.
- Compare the risks and benefits to the biosphere of applying new scientific knowledge and technology to industrial processes
- Propose and defend a course of action on a multi-perspective social issue.
- Describe the role peer review has in the development of scientific Knowledge.
_ Identify examples where scientific understanding about an ecosystem was enhanced or revised as a result of human invention or related technologies.
– Discuss the improvements that have occurred with respect to pest control.
Define sustainability
Ø Sustainable development – the development of our resources to meet both the current demands and the long-term demands of the resource; the practice of managing a resource in such a way that it will meet the needs of the present without jeopardizing the needs of future generations.
Ø Discuss historical attitudes and practices in the fishing industry, the forestry, the moose population and other resources in relation to sustainability.
Ø Read the Lorax by Dr. Seuss (Appendix A).
Ø Complete activity: A Sustainable Resource (Appendix A).
Define a paradigm and paradigm shift.
Ø Paradigm – A generally accepted viewpoint or way of thinking. The way that humans view the world is known as a paradigm. "The earth and all things on it exist for the sole benefit of humans" was an old world paradigm.
Ø Paradigm Shift – when how everyone views something suddenly changes; refers to a change in view with respect to a generally held belief. Changes in paradigms are known as paradigm shifts.
Ø Examples:
Ø Cod fishery (endless supply of cod vs. limited numbers)
Ø Endless supply of wood on NL (vs. forests are limited)
Ø Spontaneous generation (vs. biogenesis)
Ø World is flat (vs. sphere)
Ø Earth the center of the universe (vs. the sun)
Ø Models of the atom
Ø The Earth's resources are not in endless supply for our plunder.
J.E. Lovelock, a British scientist, compares the earth to a living body. Our planet is a living, self-regulating system; (in terms of climate and chemical composition).
The earth must be in a state of balance or equilibrium with every other component. What affects one part affects all parts.
Paradigm shift to come from the 1992 World Summit in Rio:
Ø The world must cut their emissions of green house gases to 5% below the 1990 level.
Ø We have the power to influence all life on this planet. With this power comes an equal responsibility for stewardship.
Ø We must recognize that we share this planet with many other creatures and that we are willing to balance our needs with those of other species
Kyoto accord:
Ø Attempt to reduce the greenhouse gas emissions 5% below 1990 levels.
Ø Each country would be given so many credits. If they used up all their credits, they would have to pay a fine or fee.
Comment on the statement – Canada should (should not) ratify the Kyoto accord
Examine historical attitudes and practices in relation to those of sustainability.
Changes in our paradigms about our forests:
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 forests extended as far as the eye could see, and beyond. The forest would simply grow new trees to replace those taken. People would never have to worry about having enough trees for their use. 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, 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 (large hook with an attached lead weight fashioned like a fish) attached to a length of line. The jigger was thrown over the side of the boat and allowed to sink to the bottom. The jigger would then be brought up just off the bottom and jigged up and down until it struck a cod. The cod was then hauled to the surface and thrown into the boat at the fisherman's feet. This cycle was repeated until the boat was full.
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. As a result of modern technology, 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?
Discuss how attitudes towards pesticides have changed.
Use of pesticides over the course of human history
Ø First-Generation Pesticides
o As early as the 500BC sulfur was first used to repel insects
o During the 15th century arsenic, lead and mercury were applied to crops as insecticides
o In 1763 French gardeners began using nicotine sulfate, a chemical extracted from the tobacco plant, to kill insect
o By the mid 1800’s two more plant extracts were being used: Head of the chrysanthemum and the Root of a tropical legume
o Many plants have developed chemical defenses against animals
Ø Second-Generation Pesticides
o Chemical made in the lab
o In 1939 Paul Mueller created DDT
o Over 500 chemical pesticides are registered for use in Canada alone
o 2.3 million tons of pesticides are used every year à 0.4 kg for every person
Chemicals taken from plants create a much lower risk for humans and the ecosystem
Many people now consider pesticides themselves to be a problem and many provincial and municipal governments have banned their usage in many locations. The town of GFW has now banned the sale of these products in local stores and their usage must be regulated by certified lawn care specialists. This is a major paradigm shift in this field.
Farmers use of pesticides:
Ø 30% of the annual crop in Canada is lost due to pests
Ø Cost
Ø In 1954 three million tones of wheat from the Prairies was destroyed by stem rust
Homeowners may use pesticides:
Ø To grow nice/productive gardens
Ø Control lawn and reduce unwanted weeds/pest
Discuss how attitudes towards forests have changed with respect to commercial usage, residential usage and replanting programs.
Many individuals and companies now understand the proper need for a sustainability program for the forestry. This has led to reductions in the amount of wood that can be cut for residential purposes and has seen major changes in the industry related to cutting practices, replanting and other issues related to silviculture.
Forestry companies use pesticides on huge tracks of forest land
Ø Spruce budworm
Ø From 1986 to 1990 NB dispensed about 170,000 kg of chemicals over 443,000 ha every year to control the growth of budworms
People are concerned about spraying pesticides close to communities and in the watershed that provides communities with drinking water.
Ø Public ideas about chemicals
Ø Unknown effects of chemicals
Define ecology and ecosystem
Ecology - The study of the interactions among living organisms and between organisms and their non-living environment. (Oikos – the place where one lives; logos – the study of).
Ecosystem - An area, which includes the relationships between populations of species and between those populations and the non-living (abiotic) factors in their environment. An Ecosystem is a community of organisms and the physical environment in which it lives.
Ecosystems are dynamic (always changing) and change be either natural or artificial (man-made). The area between and connecting 2 or more ecosystems is called an ecotone (the grassy meadow found between a pond and a forest).
Population - All of the members of the same species in an ecosystem or habitat.
Community - The collection of all the populations of species in the ecosystem.
Define abiotic factors
Abiotic factors are nonliving factors (were never alive) in an ecosystem.
Abiotic factors:
Ø Temperature (Environmental temperature affects biological processes and the ability of most organisms to regulate their temperature. Few organisms have active metabolisms at temperatures below 0oC or above 45oC because enzymes function best within a short range of temperature and become denatured if the temperature is too high).
Ø Amount of sunlight (Sunlight is the ultimate source of energy for all photosynthetic organisms which in turn provide the resources for other living things (in most ecosystems). Light also affects the development and behaviour of many organisms).
Ø Strength and direction of wind
Ø Soil (inorganic and organic soil nutrients) Inorganic soil nutrients include minerals such as phosphates, nitrates, potassium, magnesium and a host of other minerals derived from rocks. Organic nutrients include organic compounds in humus which promote the growth of bacteria, fungi, and a host of other organisms beneficial to the soil. The physical structure, water holding potential, pH, and nutrient level of soil limit the distribution of plants and in turn the animals that inhabit a terrestrial region.
Ø Space (All organisms require enough space or territory to insure adequate resources to food, water, shelter, and mates).
Ø Oxygen (Most living organisms require oxygen for cellular respiration, which is a process that releases energy from food).
Ø Water (Water (humidity) is necessary for all life. The ability to find water, to maintain water balance, and to conserve water help determine the habitat range for each species).
Define biotic factors
Biotic factors are the living factors/components found with an ecosystem. It includes any once-living factors. Biotic factors include all other organisms that interact with the individual both of the same species and all other species.
Ø Predator-prey relationships (important biotic factor which helps to limit the size of populations within an ecosystem. A predator is an animal that kills and eats another animal for food. The prey is the hunted animal. An example is the lion and the zebra. When a lion kills a zebra for food, the lion helps to prevent the overpopulation of the zebra. If the number of zebra declines too much the lion will starve. There is a balance between the number of predator and prey in any ecosystem.
Ø Food chains/webs
Ø Disease (bacteria, etc.) Disease is the result of infection by fungi, bacteria, virus, and other pathogens. Disease is an important biotic factor because disease tends to reduce the number of organisms within the community.
Ø Competition (struggle for survival that occurs between two organisms either of the same or different species. Competition tends to limit the size of the population keeping it in balance with the available resources.)