unit 12 human impact on the environment human impact on the environment 1
TRANSCRIPT
Unit 12Unit 12 Human Impact Human Impact
on the on the EnvironmentEnvironment
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Humans depend on their environment for:
• Food• Water• Shelter• Clean Air
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Renewable Resources
• A resource is something that is ready to use if or when it is needed.
• Renewable resources can regenerate and are replaceable.
• But, they still can be limited in availability• As an example, fresh water is renewable but
overuse and drought can sometimes make it scarce.
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Nonrenewable Resources• Once they’re used they cannot be replaced.
• For example, fossil fuels take hundreds of millions of years to form, burning them as an energy source means they are gone.
• Fossil fuels include coal, oil , and natural gas.
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Renewable Resource
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Nonrenew
ableResource
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Renewable
Resource
Nonrenew
able
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RenewableResource
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Renewable Resource
Overconsumption of Resources
The U.S. has only 4.6% of the world’s population, yet we consume 40% of the earth’s natural resources.
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World Population and Resources
What is the this cartoon trying to tell us?
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World Population
What is the message being conveyed by this cartoon?
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Reached on October 31,2011
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The trend shown on the graph would most likely result ina.a decreased demand for deforestationb.an increase in available freshwaterc.a decrease in air pollutiond.an increased demand for land use
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The trend shown on the graph would most likely result ina. decreased demand for deforestation• an increase in available freshwater• a decrease in air pollution• an increased demand for land use
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Which human activity will most likely have a negative effect on global stability?
A)decreasing water pollution levelsB) increasing recycling programsC) decreasing habitat destructionD) increasing world population growth
Regents Practice
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Which human activity will most likely have a negative effect on global stability?
A)decreasing water pollution levelsB) increasing recycling programsC) decreasing habitat destructionD) increasing world population growth
Regents Practice
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Which human activity would most likely deplete finite resources?
A) use of natural enemies to eliminate insect pestsB) development of wildlife refugesC) governmental restriction of industrial pollutionD) uncontrolled population growth
Regents Practice
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Which human activity would most likely deplete finite resources?
A) use of natural enemies to eliminate insect pestsB) development of wildlife refugesC) governmental restriction of industrial pollutionD) uncontrolled population growth
Regents Practice
Destructive Consequences of Human Activity
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Human activity damages the biosphere and has created serious environmental concerns.
•Ozone Depletion
• Acid Rain
• Global Warming
•Biomagnificaiton of Pollutants
• Loss of Biodiversity 22
What is the Ozone Layer?
•The ozone layer is found in the upper atmosphere and it is composed of three oxygen (O3)molecules. It limits the amount of ultraviolet light (UV) energy that reaches the Earth’s surface.
•Ozone actually absorbs UV radiation and prevents it from reaching the earth.
• UV light damages the DNA of plants and animals which can cause skin cancer and other diseases.
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How can the Ozone layer be damaged?•Various air pollutants, such as chlorofluorocarbons (CFCs), enter the upper atmosphere and break down ozone molecules.
•CFCs have been used as refrigerants, as propellants in aerosol sprays, and in the manufacture of plastic foams. •When ozone breaks down, the ozone layer thins, allowing more UV radiation to penetrate and reach the surface of the earth.
•This area of major ozone thinning is called the ozone hole and it is located above Antarctica at the south pole.
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1. CFC’s are released a rise into the stratosphere.
2. Sunlight breaks down the CFC’s, releasing chlorine.
3. Chlorine destroys the ozone (O3) molecules.
4. More UV (ultraviolet) rays reach the Earth’s surface, raising the risk of skin cancer.
These images of the ozone hole were taken by NASA between September 1981 and September 1999.
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This year’s Antarctic ozone hole was smaller than in recent years, both in terms of area and depth, according to the World Meteorological Organization’s (WMO’s) Antarctic Ozone Bulletin. Using information gathered from the ground, from weather balloons and from satellites, the Bulletin said that the ozone hole area reached zero on November 10, 2013 – earlier than in recent years.
Ozone Update !
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What will the continued depletion of the ozone layer most likely cause?
A) an increase in skin cancer among humansB) a decrease in atmospheric pollutantsC) an increase in marine ecosystem stabilityD) a decrease in climatic changes
Regents Practice
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What will the continued depletion of the ozone layer most likely cause?
A) an increase in skin cancer among humansB) a decrease in atmospheric pollutantsC) an increase in marine ecosystem stabilityD) a decrease in climatic changes
Regents Practice
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What is Acid Rain?
•Acid Rain is actually any form of precipitation (rain, snow, fog or dew) that contains high concentrations of sulfuric and nitric acids.
•The acids can have harmful affects on the environment and the organisms living there.
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Acid Rain can Damage Forests
•Acid rain can be extremely harmful to forests. Acid rain that seeps into the ground can dissolve nutrients, such as magnesium and calcium, that trees need to be healthy.
•Trees that are located in mountainous regions at higher elevations, such as spruce or fir trees, are at greater risk because they are exposed to acidic clouds and fog, which contain greater amounts of acid than rain or snow
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The damage first appears in individual leaves and limbs.
It doesn’t take long before the entire tree is damaged and dies off.
Damage to Forests !
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Acid Rain Damages Buildings and Objects
•Acid rain can also have a damaging effect on many objects, including buildings, statues, monuments, and cars.
• The chemicals found in acid rain can cause paint to peel and stone statues to begin to appear old and worn down, which reduces their value and beauty.
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Damage to Buildings and Objects
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Acid Rain causes Acidification of Lakes and streams
•Some types of plants and animals are able to tolerate acidic waters. Others, however, are acid-sensitive and will be lost as the pH declines.
•Generally, the young of most species are more sensitive to environmental conditions than adults. At pH 5, most fish eggs cannot hatch. At lower pH levels, some adult fish die. Some acid lakes have no fish.
•The chart below shows that not all fish, shellfish, or the insects that they eat can tolerate the same amount of acid; for example, frogs can tolerate water that is more acidic (i.e., has a lower pH) than trout.
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What is the Water Cycle?
•The water cycle or hydrologic is a continuous cycle where water evaporates,
travels into the air and becomes part of a cloud, falls down to earth as
precipitation, and then evaporates again. This repeats again and again in a
never-ending cycle. Water keeps moving and changing from a solid to a liquid
to a gas, over and over again.
•Would you believe that a dinosaur could have once used your last drink
of water? Water on earth today has been here for millions of years. Because of
the water cycle, water moves from the earth to the air to the earth again. It
changes from solid to liquid to gas, over and over again.
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Fun Facts •Without water, the earth would look like the moon.
•All living things need water to live. People can live several weeks without food, but only a few days without water. We should drink six to eight glasses of water each day!
•Water makes up 83% of our blood, 70% of our brain, and 90% of our lungs. Overall, our bodies are 70% water. •A tomato is about 95% water. An apple, a pineapple, and an ear of corn are each 80% water.
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What Causes Acid Rain?
•Burning of fossil fuels (such as coal) and other industrial processes release into the air pollutants that contain sulfur dioxide and nitrogen dioxide.
• When these substances react with water vapor, they produce sulfuric acid and nitric acid.
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The Acid Rain Process
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What can be done to prevent acid rain? Conserve Energy!
•Since energy production creates large amounts of the pollutants that cause acid rain, one important step you can take is to conserve energy.
•Turn off lights, computers, televisions, video games, and other electrical equipment when you're not using them.
•Encourage your parents to buy equipment that uses less electricity, including lights, air conditioners, heaters, refrigerators, and washing machines. Such equipment might have the Energy Star label.
•Walk, ride or carpool.46
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Regents Practice Question
In lakes that are exposed to acid rain, fish populations are declining. This is primarily due to changes in which lake condition?
A) Size B) temperature C) pH D) location
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Regents Practice Question
In lakes that are exposed to acid rain, fish populations are declining. This is primarily due to changes in which lake condition?
A) Size B) temperature C) pH D) location
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Regents Practice Question:
Which situation is a result of human activities?
A)decay of leaves in a forest adds to soil fertility
B) acid rain in an area kills fish in a lake
C) ecological succession following volcanic activity reestablishes an ecosystem
D) natural selection on an island changes genefrequencies
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Regents Practice Question:
Which situation is a result of human activities?
A)decay of leaves in a forest adds to soil fertility
B) acid rain in an area kills fish in a lake
C) ecological succession following volcanic activity reestablishes an ecosystem
D) natural selection on an island changes genefrequencies
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What is a greenhouse?•A greenhouse is made of glass. It traps the Sun's energy inside and keeps the plants warm, even in winter.
•It has glass walls and a glass roof. People grow tomatoes and flowers and other plants in them. A greenhouse stays warm inside, even during winter.
•Sunlight shines in and warms the plants and air inside. But the heat is trapped by the glass and can't escape. So during the daylight hours, it gets warmer and warmer inside a greenhouse, and stays pretty warm at night too.
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What is the Greenhouse Effect ?
Earth's atmosphere does the same thing as the greenhouse. Gases in the atmosphere such as carbon dioxide do what the roof of a greenhouse does. During the day, the Sun shines through the atmosphere. Earth's surface warms up in the sunlight. At night, Earth's surface cools, releasing the heat back into the air. But some of the heat is trapped by the greenhouse gases in the atmosphere. That's what keeps our Earth a warm and cozy 59 degrees Fahrenheit, on average. 53
•The greenhouse effect is now getting too strong, Earth is getting warmer and warmer. Too much carbon dioxide and other greenhouse gases in the air are making the greenhouse effect stronger.
•Too much heat energy is getting trapped in our atmosphere.
The Point Is…
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What is Global Warming?
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•Global Warming refers to an increase in the Earth’s atmospheric and oceanic temperatures due to an increase in the greenhouse effect resulting from increased CO2 emissions.
•Since the Industrial Revolution, CO2 output has increased by nearly 40% as compared to pre-industrial levels.
•There is more CO2 in the atmosphere than at any time in the last 800,000 years.
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Deforestation Contributes to Global WarmingDeforestation is the removal of a forest and the conversion of the land into nonforest use.
•The trees are no longer available to take in the CO2 gas as part of the process of photosynthesis.
Examples:FarmingRanchingRoadwaysLogging
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Explanation of the causes of global warming
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Current Global Conditions
•Since 1850 there has been a rise in the Earth’s temperature of approximately
1° C or approximately 1.8° F.
•It is an average of 1degree which means that some places are affected more than others.
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Global Warming and the Arctic Region
•Average temperatures in the Arctic region are rising twice as fast as they are elsewhere in the world. Arctic ice is getting thinner, melting and rupturing.
•The polar ice cap as a whole is shrinking. Images from NASA satellites show that the area of permanent ice cover is contracting at a rate of 9 percent each decade. If this trend continues, summers in the Arctic could become ice-free by the end of the century.
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Is Global Warming Killing Polar Bears? Sadly, yes.
They have to stay on shore more, because the ice forms later in the year and lasts for fewer months. Polar bears need the ice to live. They hunt seals from the ice floes. Less time on the ice means less food to eat. Polar bears do not hibernate. They have to have enough fat storage build up throughout the winter to last them throughout the spring, summer, and parts of fall.
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What is global warming doing to the environment?
1. Global warming makes the sea rise due to polar ice caps melting. When the sea rises, the water covers many low land islands. This is a big problem for many of the plants, animals, and people on islands.
2. The water covers the plants and causes some of them to die. When they die, the animals lose a source of food, along with their habitat. 3. The animals may die also or lose their homes. As a result, they would also have to leave the area. This would be called a break in the food chain, or a chain reaction, one thing happening that leads to another and so on. 63
Global Warming Affects Climate
•As the climate gets warmer, we can expect more extreme weather.
•Warmer oceans fuel more intense hurricanes, meaning destruction and flooding in coastal areas.
•Wildfires and drought are plaguing southern and western states.
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What is the Carbon Cycle?
•Carbon atoms continually move through living organisms, the oceans, the atmosphere, and the crust of the planet.
•This movement is known as the carbon cycle.
• The paths taken by carbon atoms through this cycle are extremely complex, and may take millions of years to come full circle.
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How does the Carbon Cycle work?•In the atmosphere, carbon is attached to some oxygen in a gas called carbon dioxide. (CO2)
•Plants use carbon dioxide and sunlight to make their own food and grow. The carbon becomes part of the plant.
•Plants that die and are buried may turn into fossil fuels made of carbon like coal and oil over millions of years.
•When humans burn fossil fuels, most of the carbon quickly enters the atmosphere as carbon dioxide.
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Regents Practice Question
Global warming has been linked to a decrease in the
A) size of the polar ice capsB) temperature of the EarthC) rate of species extinctionD) rate of carbon dioxide production
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Regents Practice Question
Global warming has been linked to a decrease in the
A) size of the polar ice capsB) temperature of the EarthC) rate of species extinctionD) rate of carbon dioxide production
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Regents Practice Question
One possible reason for the rise in the average air temperature at Earth’s surface is thatA) decomposers are being destroyedB) deforestation has increased the levels of oxygen in the atmosphereC) industrialization has increased the amount of carbon dioxide in the airD) growing crops is depleting the ozone shield
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Regents Practice Question
One possible reason for the rise in the average air temperature at Earth’s surface is thatA) decomposers are being destroyedB) deforestation has increased the levels of oxygen in the atmosphereC) industrialization has increased the amount of carbon dioxide in the airD) growing crops is depleting the ozone shield
BiomagnificationOf Pollutants
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What is Biomagnification ?
It is the increase in concentration of a substance that occurs as you move up higher in the food chain.
•As one organism eats another, the toxin becomes more and more concentrated.
•Some toxins, such as the pesticide DDT, concentrate in plants and animals.
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What is DDT ?•DDT stands for dichloro, diphenyl trichloroethane.
•DDT was a pesticide used on crops in the 1970’s to kill mosquitoes. At the time people were afraid of getting malaria from mosquitoes. People thought DDT did not hurt any animals because it did not effect humans, but they were wrong.
•DDT was affecting many animals other then mosquitoes.
•When mother birds ate the animals exposed to DDT, it concentrated or accumulated in her body and caused her egg shells to be formed with a very thin shell and babies couldn’t hatch because their shells cracked.
•Rachel Carson's book Silent Spring helped make people want to ban DDT. 74
DDT Half Life DataDDT has a half-life of 15 years, which means if you use 100 kg of DDT, it will break down as follows:
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Loss of Biodiversity
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What is Biodiversity?
•Biodiversity refers to the variety of living organisms in an ecosystem.
•The larger variety means a greater stability to the ecosystem.
•The diversity results from variations in the genetic make-up of each organism including plants and animals. 78
Loss of Biodiversity
•As a result of human activities, especially the destruction of tropical rain forests and other habitats, plants and animals are becoming extinct at a faster rate than the planet has ever previously experienced.
•If they were to survive, scientists believe many of the disappearing plants could become useful to humans as medicines, foods, and industrial products.
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Throughout history, humans have used plants to treat all kinds of illnesses. Today, about 40 percent of our prescription medicines come from plant extracts or synthesized plant compounds. Plant-based medicines are everywhere, including the shelves of our local drugstores.
Plant Medicines
Derived from: Mint (mentha)Parts used: Leaves
Active ingredient: Menthol. Mentholis now made synthetically or frompeppermint or other mint oils.
Use: Relieves itching, relaxes musclesoreness, opens congested sinuses andupper respiratory tract
Mint can be grown easily in agarden. The leaves can be used fortea, salads, and as an herb in foods.
Throat Lozenges, MuscleCreams, and Cold and Nasal Medicines
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Derived from: Cinchona tree Part used: Bark
Active ingredient: Quinine. Quinine andquinidine are both extracts from cinchona bark.Both are still used against malaria parasites.
Use: Treatment for malaria10,000 tons of cinchona bark is harvestedannually to make drugs to treat malaria.
Quinine (Malaria Drug)
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