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Ecology, Population Dynamics. Levels of Biological Organization. Species ; The lowest level or most exclusive; The technical name given for a kind of organisms. A species can interbreed and produce a fertile offspring that can produce more offspring with each other.
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Levels of Biological Organization • Species; The lowest level or most exclusive; The technical name given for a kind of organisms. A species can interbreed and produce a fertile offspring that can produce more offspring with each other. • Population;consists of a group of interacting individuals of the same species that occupy a specific area at the same time • Community; populations of all different species occupying a particular space
Levels of Biological Organization • Ecosystem; a community of different species interacting with one another and the nonliving environment of matter and energy • Biotic factors ; are living components of an ecosphere. • Abiotic factors; are non-living components of an ecosphere such as minerals and nutrients, sunlight, temperatures, precipitation, etc…. • Biosphere; Zone of the Earth where life is found. Also called the ecosphere. Consists of the interaction of living and nonliving components together.
Ecological Terminology • Ecology; The study of relationships between organisms and their environment • Environment; the air, water, minerals, organisms, and all other external factors surrounding and affecting a given organism at any time.
Ecosystems • All members of a community, along with their physical and chemical environments • Vary greatly in size • Diversity promotes stability and productivity • Dynamic • energy flow is one way • chemicals and matter are cycled • Change over time (succession) Coral Reefs are a rich, diverse and productive ecosystems A coastal wetland on Lake Superior, Wisconsin.
Biomes • Biomes are terrestrial sets of ecosystems characterized by rainfall, temperature, and the dominant form of vegetation. A single biome occupies a large geographic area and usually is found on more than one continent. • Tropical Rainforests • Savannas • Deserts • Temperate Grasslands • Temperate Deciduous Forests • Coniferous Forests • Arctic Tundra Grasslands in the Great Sand Dunes National Monument and Preserve Prairie Creek Redwoods Sate Park
Aquatic Ecosystems • Freshwater • Flowing Water • Lakes • Wetlands • Estuaries (salt and fresh mixed) • Oceans • Intertidal or littoral • Coastal or neritic • Coral Reefs • Open Ocean • Benthic Snake River with Grand Tetons in background Mountain Lake in Grand Teton National Park
Energy Flow in Ecosystems • Food Chains and Food Webs • Energy is described as the basic currency of ecosystems, and the amount of energy controls the size of those populations. • All organisms are potential sources of food, the sequence of organisms, each a source of food to the next, is called a food chain. • Organisms are assigned a feeding level or trophic level depending on whether it is a producer or consumer or ect...
Energy Flow in Ecosystems • Real ecosystems are more complex than this however, one organism often feeds off of several different organisms and food chains to form a interconnected food web.
Energy Flow in Ecosystems • Transfer of energy between trophic levels is inefficient because much of the energy captured is lost to building and maintaining the bodies of organisms. Less than 10% of the energy obtained by organisms at each level is available to organisms in the next trophic level. • A pyramid of energy flow illustrates this energy loss for a simple food chain. • Energy pyramids always have a triangle shape because energy is always lost going up the pyramid. • This also explains why hawks, tigers, and sharks are the first to suffer when an ecosystem is disrupted and vulnerable to extinction.
Limits on Population Growth • Remember a population is a group of organisms of the same species that live within a given area • Population density is total population size per unit of area. • Population densities depend on: • Interactions within the environment • Quality of habitat • Density dependent factors; things that are influenced by the # of organisms in the area. Examples; Diseases, competition, food supply, predation. • Density independent factors: things that are not influenced by the # of organisms in the area. Examples; Natural disasters and environmental disturbances. Water and shelter are critical limiting factors in the desert. Fire is an example of a Density independent Limiting factor.
Exponential, Linear, and Logistic Growth • Linear growth. the quantity increases by a constant amount per unit of time. For example a train accelerating from 1 to 2 to 3, 4, 5 6 7 ECT.. • Once there were two kings from Babylon who enjoyed playing chess, with the winner claiming a prize from the loser. After one match, the winning king asked the loser to pay him by placing one grain of wheat on the first square of the board, two on the second, four on the third, and so on. The # was doubled until all 64 squares were filled. The losing king, thinking he was getting off easy, agreed. It was a big mistake. He bankrupted his kingdom and still could not fulfill the promise. In fact that was more grain than ever harvested. The last square would have 1.8 * 10^19 grains on it or 180,000,000,000,000,000,000.
Exponential, Linear, and Logistic Growth • Exponential growth the quantity increases by a fixed percentage of the whole in a given amount of time. Even a .001 or .1 percent will yield a exponential growth. The amount grows slowly at first then explodes. When graphing a exponential curve it appears to make a “J” shape. • How long does it take to double a resource use, or population size. A quick way to calculate it is to use the rule of 70. • 70/percent growth rate = double time in years. • for example in 1996 the population the worlds pop grew by 1.55% so 70/1.55 = 45 years
Exponential, Linear, and Logistic Growth • Logistic growth is slowed by population-limiting factors and will have “S” curves. • Carrying capacity is the maximum number of organisms that can be supported in a given habitat. • Multiple factors may limit population growth and create a declining birth rate or increasing death rate. • limited food supply • the buildup of toxic wastes • increased disease • predation
Population Growth Exponential vs. Logistical Growth
Lesson 2: Human Population Growth Big Question Why Is Human Population Growth the Underlying Environmental Problem?
Human Population Growth • The human population continues to grow rapidly. The fact is, humanity today represents something unprecedented in the history of the world: never before has one species had such a great impact on the environment in such a short time and continued to increase at such a rapid rate. These qualities make the human population the underlying environmental issue. • To put it into perspective: every second, twice as many children are born as people die. The impact of this is that 2.3 people are added to the world population every second. There are over 31 million seconds in every year, which means that about 72 million people are added each year. These dynamics have profound impact on our environment.
Human Population Growth • The birth rate is the number of individuals born during a specified time interval. • The death rate is the number of individuals who die during that same time interval. • The growth rate is the difference between birth rate and death rate; the net change in the size of the population. • Discussions about the human population problem generally include predicting how large the population will grow over time. How is this done? The simplest forecasting method is to assume that the population undergoes exponential growth at a constant rate per time period rather than by a constant amount.
The history of human population growth Figure 35.8A
Major Periods of Human History • The early period of hunters and gatherers - less than a few million people • The rise of agriculture - first major increase in the human population • The Industrial Revolution - improvements in the food supply and health care led to a rapid population growth • Today -growth has slowed in industrialized nations but is increasing rapidly in many less developed nations
The Logistic Growth Curve • Exponential population growth cannot go on forever; people would eventually run out of food and space. • The birth rate should decline and the death rate should rise, so that the growth rate slows to zero. • The population should follow a smooth S-shaped curve. • The population increases exponentially when small, so the curve rises steeply. • Then the rate of growth gradually declines, until it reaches an upper population limit - the logistic carrying capacity. • However death rates do not increase if there are ongoing improvements in health care and food supplies.
Quality of Life and the Human Carrying Capacity of the Earth • How many people can actually live on Earth at the same time? The answer depends on what quality of life people desire and are willing to accept. The 7 billion (6,973,738,433 ) currently on Earth could probably not all live like Americans, much as they might want to. • One way we can make judgments is thru ecological footprints. • An ecological footprint represents the amount of productive land needed to support a nation’s resource needs.
The Magnitude of our Trash Problem • The U.S. is the #1 trash-producing country in the world at 1,679 pounds per person per year. • This means that 5% of the world's people generate 40% of the world's waste. • 305,529,237 = US population • About 4.4 pounds per person per day, would be 672,000 tons or 97,000 garbage trucks, Lined up end to end. 97,000 trucks is 570 miles, more than Raleigh to Tampa Florida. IN ONE DAY .
Trash History • 1890sAverage 0.6 lbs/person/day without ash. Coal and wood fires heated most homes and buildings, so people had to discard lots of ash. Few people had trash cans in their homes. They fed kitchen waste to dogs and pigs; threw garbage into streets, gardens, and outdoor toilets; and burned some trash. • 1950sAverage 2.6 lbs/person/day. After World War II, the U.S. population grew quickly. Many families had more money to buy new clothing, cars, and furniture, even when the old ones weren't worn out. New disposable products encouraged spending -- and waste. Garbage now includes tin cans, aluminum cans, junk mail, and cellose, but little plastic. • 1990sAverage 4.6 lbs/person/day We've filled our homes and work places with time and energy saving products and gadgets. Garbage now includes plastic bottles, obsolete electronics, styrofoam cups, plastic food wrappers, used batteries, glossy magazines and computer paper.
The E-waste crisis started about the time our present high-school students were born. Photo courtesy of Recycling Council of Ontario
Evolution of E-Waste E-Waste 19501960 1970 1980 1990 2000
What are we throwing away? If we recycled glass, paper, cardboard and metal food containers, as well as composted our food scraps what percentage of trash would be eliminated from the waste stream? MUNICIPAL SOLID WASTE IN 2007 254.1 million tons
Landfills • ~65% of US waste ends up in landfills • 100% of Wake County waste ends up in the landfill. • A garbage graveyard in which wastes are spread out in thin layers, compacted and covered with a layer of clay or plastic foam. • Leachate or garbage juice is pumped to storage tanks and is treated internally or externally. • Methane fumes from decomposition are pumped out from wells and stored. Sometimes it can be burnt for power production or just flamed off.
Do you know where your garbage ends up at? • Here is a aerial photo of the Holly Springs landfill. • Compare the size of the landfill to your local school. • Both pictures use the same scale
The Link between Solid Waste & Climate Change • Methane (CH4), is a greenhouse gas produced in landfills. • Global Warming Potential of methane is 25 times greater than carbon dioxide. • Landfills are second only to livestock industries as the greatest anthropogenic source of methane. • The manufacture, distribution, and use of products—as well as management of the resulting waste—all result in emissions of greenhouse gases that affect the Earth’s climate. Reduction and Recycling reduce production of green house gases.
Incinerators • The US burns 17% of its garbage in incinerators. Incinerators cost more than landfills. However in density populated area that lack land for landfills rely on incinerators to handle most of their garbage. • Burning can reduce the volume of garbage by 60-90%. But it produces ash and creates harmful gases and particles that must be filtered out of the air. • Many experts believe incineration can work safely, but it requires adherence to strict standards and regulations. A 1994 Supreme Court decision requires operators to test their ash and, if it's toxic, to handle it as a hazardous waste. • Citizens are often reluctant to accept an incinerator in their own community because of concerns about safety, odors, and the conflict between recycling programs and incineration. • Economic benefit of the waste to energy plants depends on the price of competitive energy sources.
A Duel Problem: The issue is not just the volume of trash we are producing, but also the hazardous composition our trash. EXAMPLE: These elements in electronic devices can become hazards if set on fire, placed in acid baths, inhaled as dust, or dumped in waterways. • Circuit boards contain cadmium, lead or beryllium • Cathode ray tubes(CRTs)are coated with barium and phosphor, in addition to containing 2-6 lbs of lead. • Batteries are loaded with lead, mercury, and/or cadmium. • Components, switches, or lights contain mercury-, beryllium- and Polychlorinated Biphenyl-containing materials.
Mercury 80200.5 Electrical switches, batteries, barometers, thermometers, fluorescent and neon lights Hg • \ Valuable Properties: Mercury conducts electricity and expands at a constant rate in response to changes in pressure or temperature. In its vapor state, mercury can combine with other gases to form more complex molecules that emit light when charged with electricity. “Mad as a hatter” Hazardous Properties: Exposure to high levels of metallic, inorganic, or organic mercury can permanently damage the brain, kidneys, and developing fetus. Effects on brain functioning may result in irritability, shyness, tremors, changes in vision or hearing, and memory problems.
Lead Lead gasoline Lead Paint Lead Shot for waterfowl outlawed 82207.2 Pb Lead-acid batteries, solder, x-ray protection, paint Valuable Properties: Lead is a very corrosion-resistant, dense, ductile, and malleable metal. Hazardous Properties: Lead can cause damage to the central and peripheral nervous systems, blood system and kidneys. Effects on the endocrine system have also been observed and its serious negative effects on children’s brain development has been well documented. The toxicity of lead comes from its ability to mimic other biologically important metals, most notably calcium, iron and zinc which act as cofactors in many enzymatic reactions and interfering with the enzyme's ability to catalyze its normal reaction(s).
PVC • Cabling, insulation of wires, and computer housings, although many computer moldings are now made with the somewhat more benign ABS plastics. Valuable Properties: PVC is strong, rigid, light weight, waterproof and flame-resistant. PVC also can be made into a soft and flexible plastic by mixing it with plasticizers. Hazardous Properties: The PVC itself isn't toxic or carcinogenic, but the monomer used to make PVC, vinyl chloride, is carcinogenic and can be harmful to people who work in the factories where PVC is made. Dioxin (polychlorinated dibenzo-p-dioxins) is produced as a byproduct of vinyl chloride manufacture and from incineration of waste PVC in domestic garbage. Also the plasticizers that make PVC soft and flexible can be toxic and carcinogenic.
How can we reduce our waste production? • The Four Rs: Rethink, Reduce, Reuse, Recycle • We know that most items we purchase will be thrown away eventually, so why not design for the “end of life” of the product? Engineers and product designers need to address: Rethinking means looking at how we manufacture products and trying to create solutions with less waste in the first place. • Packaging: materials comprise 65% of our waste. • Toxic substances: substitute with less toxic or benign materials (i.e. lead-free solder) that can be harmlessly disposed of or recycled. • Engineer recycling into the design of the computer. (or any mechanical product) Create components which are easily interchangeable for updating or removed for recycling.
Paying for a Bad Design • “Electronics were designed to be disposed of rather than recycled, therefore it is difficult and costly to separate the high-value recyclable materials and the toxic components from discarded electronics."
REDUCE • Source “reduction” is reducing waste before you purchase it, or by purchasing products that are not wasteful in their packaging or use. • Making a new product requires a lot of materials and energy; raw materials must be extracted from the Earth and the product must be fabricated and then transported. • You can practice reduction by selecting products that do not have to be added to landfills or the waste stream in general. • Examples; First and foremost, buy and use less! • Start making wise “package “selections • Think BIG! Buy in bulk. Avoid single serve container. • Buy concentrates rather than diluted products, less packaging • Use Durable goods longer vs. Disposable. Repair when broken vs. just new. • Say NO to junk mail. Call toll-free numbers in unwanted catalogs and ask to be removed from mailing lists. • Use the internet to obtain and pay bills, news, catalogs, ect.. to reduce waste stream. • Start a garden for non-processed and non-packaged foods. • Compost to transform household kitchen scraps into a rich Earth-like material to add to gardens.
REUSE • To reuse is to use an item again after it has been used. This includes conventional reuse where the item is used again for the same function or “new life” where it is used for a different function. • Conventional examples include; • Delivery of milk in refillable bottles • Retreading tires • Using “hand me downs” and shopping at thrift stores instead of always buying new clothing. • Using canvas bags for shopping instead of plastic bags. • Using your own reusable bottle instead of disposable.
Recycle • This term is often misused, or used too broadly. Proper definition of recycling is "the separation and collection of materials for processing and manufacturing into new products, and use of these new products to complete the cycle". This takes more energy when remanufacturing! • Should be the final step, after rethinking product design and reducing waste production through wise purchasing and reuse. • We are “closing the cycle” when we purchase items made up recycled material. • “Downcycling”occurs when the new product is of mixed materials and can not be recycle again (i.e. carpeting and boards made of a mixture plastic bottles and sawdust).
Boom and Bust of Recycling The success of a recycling program is tied to market forces, transportation cost, and proximity to manufacturers. Should you pay for recycling? The more complex an item the more labor is needed to separate materials. If the labor is more costly than the recovered material than recycling is expensive. However one should also include the environmental cost of mining raw material versus recycling raw metal. Items made of a single material are costly to recycle Items made of many materials have higher labor cost to recycle
The 4 Rs Illustrated: Product Lifecycle Rethink Reduce Reduce Material Extraction Material Processing Manufacturing Use WasteManagement Reuse Reuse Repair Recycle Recycle Remanufacture Suggested by OTA, "Green Products by Design: Choices for a Cleaner Environment," 1992.
What can you do? • Learn what you can keep out of the garbage. • Recycle naturally, that is COMPOST in your own back yard • Consume wisely. Plus you can study to become a green engineer or designer
There is no “away” • There is no way to get rid of all our garbage. The best solution is to make less, then find the most appropriate way -- reuse, recycle, burn, or landfill -- to manage what's left. • Where does your trash go? Find out, if you don't know. What would your family do if your trash wasn't picked up every week?
You as an individual • You have purchasing power: • Will you select more “greenly” designed items? • Will you buy less and reuse more? • You can choose a greener lifestyle: • Will you take advantage of existing recycling programs in your community? • Will you pass along your usable goods to thrift stores, online pages like Craig’s list, Freecycle?
Hexavalent chromium anti-corrosion Because chromium can go into solution and move through soil, chromium pools and blooms (the crystallized chromium left on the surface when the water evaporates) may occur some distance from the original site of contamination. 6+ Cr Valuable Properties:It is used as a corrosion inhibitor and in hardening and corrosion protection in metal housing. Hazardous Properties: While other forms of chromium can be trace nutrients for animals and humans, hexavalent chromium is highly toxic even at low concentrations, and in some case carcinogenic, site specific cancer-lung and sinoeus (ATSDR 2000). Also Hexavalent chromium is far more reactive and soluble in water than other forms of chromium, making it more mobile in the environment (Mukherjee 1998).
49.0 Be Beryllium semi-conductor chips, ignition modules, transistors, electrical insulator Valuable Properties: Beryllium is extremely lightweight, hard, a good electrical and thermal conductor, and non-magnetic. Due to its electrical conductivity, it is used in low-current contacts for batteries and electrical connectors Hazardous Properties: Handling beryllium in its solid form, such as a finished computer part that contains beryllium, is not known to cause illness. However, some people who inhale beryllium dust or fumes will develop beryllium sensitization or chronic beryllium disease (CBD).
