Which terrestrial biome is called the breadbasket of the world

The Earth System

Earth is the third planet from the sun in our solar system. Earth orbits the sun in an elliptical (oval) path. Earth’s orbit is sometimes called the “Goldilocks zone.” Mercury and Venus travel too close to the sun to sustain life—they’re “too hot.” Planets beyond Earth travel too far from the sun—they’re “too cold.” But Earth is “just right.” (Note that there’s evidence that Mars—the Red Planet—once may have sustained microscopic life on its surface. However, conditions on the Red Planet no longer seem favorable.)

The term “Earth system” refers to the different processes and cycles that exist on the planet. All of these work together to sustain life. The four domains of the Earth system include the geosphere, the hydrosphere, the atmosphere, and the biosphere. Let’s quickly review each of these.

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The geosphere refers to the solid portion of the planet. It includes the rocks and minerals that make up the continents as well as the ocean floor. It also includes structures within Earth, including the liquid mantle and the dense, solid, metallic core. Nonliving surface ground layers, such as desert sands and volcanic rock, are part of the geosphere.

The hydrosphere includes all the water on or near Earth’s surface. The oceans are the major component of the hydrosphere. They make up 97 percent of the Earth’s water. Glaciers and polar ice caps make up about 2 percent of the hydrosphere. Only about 1 percent of the hydrosphere is made up of the liquid freshwater found in ponds, streams, rivers, lakes, and underground water reservoirs (aquifers).

Aquifers are the main freshwater source in America’s “breadbasket” states of the Midwest and Great Plains. (“Breadbasket” states get their name from the volume of wheat, a primary ingredient in bread, grown there.) The hydrosphere extends several miles above the surface of the planet into the atmosphere, mainly in the form of water vapor.

Water vapor is water in its gaseous state. Precipitation is water released from the clouds. It may take the form of rain, freezing rain, sleet, snow, or hail. It’s part of the water cycle.

For more information on the hydrosphere, follow this link: What is the HYDROSPHERE?

The atmosphere is the planet’s blanket. It allows living beings on the planet to breathe. It also protects us from the unfriendly features of the universe, such as meteors, cosmic radiation, and the effects of solar flares.

The atmosphere is made up of a variety of layers, as follows:

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· The troposphere is the densest part of the atmosphere. It starts at Earth’s surface and extends upward from about 5 miles (in the higher or lower latitudes) to 9 miles (over the equatorial regions). Most of our weather takes place here.

· The stratosphere extends from the troposphere upward about 31 miles. The ozone layer, which protects the planet from solar ultraviolet radiation, is located in this region.

· The mesosphere starts just above the stratosphere. This layer is where most meteors burn up to become “falling stars.” It extends upward for about 53 miles.

· The thermosphere extends from just above the mesosphere. It extends upward for about 372 miles. The thermosphere is the region where most human-made satellites orbit the planet. It’s also the location of the Aurora Borealis (the Northern Lights).

· The ionosphere extends upward about 600 miles from the thermosphere. This layer gets its name because it includes electrons and assorted ions, allowing for radio communications on the planet. Broadcast signals are radio frequencies that are bounced off the ionosphere.

· The exosphere extends from the ionosphere/thermosphere upward some 6,200 miles. This layer is the outer limit of Earth’s atmosphere.

For a more in-depth look at the atmosphere, access this site by NASA: Earth's Atmospheric Layers

The biosphere is the layer of Earth where life exists. It includes all life on land, water, and in the air. The list of organisms living on Earth is long and complex. It includes all plants and fungi. It includes microscopic creatures like bacteria, viruses, and ocean plankton. And, of course, it includes all animals, including humans.

Want to review Earth’s system as an animated short? Check out this video:

Ecology Defined

Ecology is the branch of biology that deals with the relationships between organisms and their environments. Ecologists employ scientific methods. They work to understand how organisms act and interact with the physical and chemical environment around them.

The term “ecology” also refers to organized efforts to understand and protect the environment. Ecologists seek to understand practices that affect the environment, such as timber clear-cutting and petroleum-based “factory” farming, and replace them with alternative, sustainable practices.

Basic Concepts of Ecology

Ecosystems

An ecosystem is a biological community of organisms and their shared environment. Many kinds of ecosystems exist on Earth. Examples include ponds, grasslands, forests, estuaries (the tidal mouth of rivers, where tides and streams meet), and marshes like the Florida Everglades.

In many cases, the actual boundaries of any ecosystem are hard to determine. Researchers work on defining specific locales. We do know that an ecosystem is made up of a community of different living (biotic) flora and fauna that interact with each other in a specific, nonliving (abiotic) environment. Abiotic factors include sunlight, the physical and chemical makeup of the environment, and the local climate pattern.

The main focus of an ecosystem study involves the processes that link living (biotic) components to nonliving (abiotic) components through energy transformations and biochemical cycling. As an example, look at the illustration of the nitrogen cycle. The nitrogen cycle is the process by which nitrogen gets from the air into the soil and then into plants and animals. Eventually it cycles back to the air.

Can you identify the biotic (living) components in the illustration? These include animals that supply wastes, plants, and decomposers (mushrooms and fungi that break down dead or decaying organisms).

The arrows show vital processes of biochemical cycling. Through these processes, nitrogen from the air is supplied to plants. Follow the arrows to track the complete cycle of nitrogen that starts in the atmosphere and returns to it. Energy transformations occur wherever you see chemical reactions in the illustration. For example, nitrogen-fixing bacteria provide nitrogen to the roots of legumes. Decomposers break down the bodies of dead organisms and return nitrogen to the soil in the form of ammonia.

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Are you interested in learning more about the nitrogen cycle? Review this presentation:

Other vital environmental cycles include the water (hydrologic) cycle, the carbon cycle, and the phosphorus cycle.

As you think about these cycles, keep in mind that ecology is defined as the interactions of organisms with one another and with the environment. That can happen in all sorts of ways. However, an ecosystem is deemed healthy if the interactions are sustainable; that is, they’re balanced and stable. In a sustainable ecosystem, the cycles work flawlessly and dependably. The ecosystem can adapt to changing seasons and the gradual change of climate patterns.

By contrast, unhealthy ecosystems are unbalanced or unstable. Ecosystems can become unhealthy in a variety of ways. For example, petroleum-based mechanized agriculture disrupts various natural cycles, such as the nitrogen cycle, by depleting or contaminating the soil.

Within the environment of an ecosystem, a habitat is the actual location in which organisms like plants and animals live. For example, the environment around the Mountain Lake Hotel in Virginia forms a specific habitat. It’s also the location of a University of Virginia environmental field station. If you scan the terrain around and beyond a particular kind of habitat such as Mountain Lake, you can establish its geographic range. The geographic range includes all the local areas that feature similar habitats.

Ecological studies may focus on individuals, populations, communities, and/or entire ecosystems. Sometimes studies focus on individuals, such as white tail deer, painted turtles, redwing blackbirds, loblolly pines, or birch trees. These studies examine reproduction, behavioral development, and physiology. When the focus is on populations, the study might examine the species’ resource needs, group behaviors, and population growth. Ecologists might focus on the sources of a species’ abundance on the one hand as well as conditions that may lead to its extinction on the other.

Studies of communities look at how the populations of different species interact with each other. For example, studies may focus on the interactions between predators and their prey. Predator and prey populations are interdependent. When predators reduce the population of a prey below a certain level, predator populations will also decrease. Other community studies might examine relationships between competing species that thrive on the same resources. For example, in Australia, the population of European feral (wild) rabbits negatively impact native grazing species like wallabies. In this context, feral rabbits are defined as an invasive species. Invasive species aren’t native to an environment and can cause harm.

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The community of organisms and their environments form an ecosystem. When we study the ecosystem itself, we’re engaged in ecosystem ecology. That is, we’re looking at how the whole system works. These types of studies focus on functional aspects of the system, including the following:

· The amount of energy supplied to the system through photosynthesis*

· The distribution of energy through the food chain

· The rates of organic decomposition and the rate at which nutrients are recycled within the system

*Photosynthesis is the process by which phytoplankton and all the many species of plants absorb energy from the sun and provide it to all life on Earth. A simplified formula for the process of photosynthesis looks like this:

6CO2 + 6H2O → (sunlight) → C6H12O6 + 6O2

In the balanced equation, 6 molecules of carbon dioxide + 6 molecules of water = glucose [C6H 12O6] + 6 molecules of oxygen.

Photosynthesis is the source of all life energy. Photosynthesis is like breathing. We inhale the oxygen from plants. Then plants absorb the carbon dioxide produced when we exhale.

Learn how energy gets into our food by watching this short presentation:

Ecological Niche

Ecological niche describes how an organism or population responds to the distribution of resources and competitors in an environment. An ecological niche includes all the resources available to a species along with the living and nonliving conditions that may have a favorable or unfavorable impact. Put another way, an ecological niche refers to all the possible interactions of a species with other species in a community. Interactions include the following:

· Competition: This occurs when two or more species compete for the same resources.

· Predation: Predators are at the top of the food chain in an ecosystem. Their survival depends on the availability of prey populations. Big fish eat smaller fish, and so on. Trophic interaction is a term used to describe feeding behaviors in an ecosystem.

· Parasitism: Parasites are organisms that live on other organisms. Many species are subject to parasites. For example, the Anopheles mosquito feeds on the blood of both animals and humans. These mosquitos can spread disease-bearing pathogens like those that cause malaria.

· Mutualism: This describes a mutually beneficial relationship between unrelated species. Pollination of flowering plants (angiosperms) offers a prime example. Bees collect pollen as a source of nutrients. As they move from flower to flower, they spread pollen to other angiosperms. This enables the reproduction (pollination) of flowering plants. Thus, bees and angiosperms have a mutual relationship.

All of the above are important, along with abiotic factors such as climate and soil type. Informally, a niche is thought of as the “role” played by a species within a community or habitat.

Biomes

A biome is different from an ecosystem. An ecosystem describes the interaction of living and nonliving things in an environment. A biome, on the other hand, is a specific geographic area that can be identified by the species living there. A biome is made up of many ecosystems. For example, the aquatic biome includes a number of ecosystems. These include ecosystems associated with phytoplankton, coral reefs, kelp forests, fish, and so on.

The five major biomes of planet Earth include desert, tundra, aquatic, forest, and grassland biomes.

· Desert Biomes Desert biomes cover about one-fifth of Earth’s land surface. Deserts form due to the low level of rainfall in an area. A primary characteristic of all deserts is low species diversity, including reptiles and small mammals like field mice and gophers. Four major types of deserts exist in this biome: hot and dry, semiarid, coastal, and cold. Hot and dry deserts include the Sahara, the Arabian Peninsula, central Australia, and the Mojave Desert in the American Southwest. Semiarid deserts can be found in areas of Utah, Montana, and the Great Basin. Coastal deserts include the far northwestern Sahara where it borders the Atlantic Ocean, and the Atacama Desert of Chile, which borders the Pacific Ocean. Cold deserts are found in places like Antarctica and Greenland. We’ll return to this topic later, as we consider the nature and extent of desertification in general as well as within our current era of climate change and global warming.

· Tundra Biomes Tundra biomes are the coldest of all the biomes. The word “tundra” comes from the Finnish word tunturia, which means “treeless plain.” Frosty landscapes, extremely low temperatures, and little precipitation characterize tundra. Tundra biomes are poor in nutrients and follow short growing seasons. There are two types of tundra: arctic tundra and alpine tundra. Arctic tundra refers to the Arctic region in the northern hemisphere, around the North Pole. Alpine tundra refers to mountain regions at high altitudes. In these areas, trees can’t grow and nighttime temperatures are below freezing.

· Aquatic Biomes Aquatic biomes fall into two groups: freshwater and oceanic (marine). Freshwater biomes include lakes, ponds, streams, rivers, and marshes or wetlands. Oceanic biomes cover about 75 percent of Earth’s surface, making them the largest biomes on the planet. The five main ocean biomes include the Pacific, Atlantic, Indian, Southern, and Arctic Oceans. Together, they link a huge number of ecosystems. Lesser oceanic sub-biomes include bays, gulfs, and estuaries. Life on Earth began in the oceans. For about a billion years, Earth’s surface was sterile. Surface life only began as plants spread inland and pumped oxygen into the atmosphere. Eventually, the ratio of oxygen to nitrogen in the atmosphere reached 21 percent. This ratio allowed amphibians to come ashore and air-breathing creatures to evolve. (Did you know that the ion balance in human blood serum is roughly identical to the ion balance of ancient oceans? That’s why it’s recommended that people switch from iodized salt to sea salt.) Earth’s oceans are critical to survival of all life on the planet. They regulate global climate patterns. They’re also the source of the water cycle, which is initiated as the surface evaporates. Of course, oceans are also home to millions of fish species, aquatic mammals (dolphins, whales), plankton, phytoplankton, mollusks, jellyfish, and so on. Phytoplankton provides most of the oxygen in the air through photosynthesis. Indeed, these tiny organisms are the basic foundation of the oceanic food chain—not to mention the foundation for all life on Earth.

· Forest Biomes Forest biomes include three main types—tropical rainforests, temperate forests, and boreal forests (also called taiga). These three kinds of forests once occupied about 70 percent of the planet’s surface. Today, due largely to deforestation, pollution, and industrial and agricultural activities, forests occupy only about one-third (30 percent) of Earth’s land area. Tropical forests are confined to regions near the equator. These forests harbor the largest array of species of all kinds. They’re also a significant source of atmospheric oxygen. The largest of the tropical forests on Earth is the Amazon basin. This area is sometimes called our planet’s “lungs” because of the volume of atmospheric oxygen it supplies. Other major tropical forest areas include the Guyana Shield of northern South America (from Guyana to Venezuela to Colombia and Ecuador), as well as regions of Indonesia, Malaysia, Vietnam, Cambodia, Thailand, and southernmost India. They also include Africa’s Congo Basin (“the Congo”) in Central Africa. This region includes the Democratic Republic of the Congo and extends into highland regions of Uganda, Rwanda, and Burundi, where we find the threatened domain of the mountain gorilla. The deforestation of tropical rainforests in Brazil and Southeast Asia is a problem. Deforestation deprives the planet of precious resources found only in rainforests. This includes amazing species diversity, an unknown number of medicinal herbs (many pharmaceutical drugs originated from tropical medicinal herbs), and, of course, the oxygen pumped into the atmosphere. Subtropical forests constitute a subdomain of tropical forests. They represent a transition zone from tropical forests to higher-latitude temperate forests. In the United States, Florida and the Gulf Coast states are thought of as subtropical climate regions. However, in most of this region, subtropical forests are mainly noticeable by their absence. In much of this region, forests and wetlands have been destroyed for urban residential development as well as agricultural and industrial development. Of course, the same may be said of temperate forests worldwide. Temperate forests, as suggested by their name, occupy Earth’s temperate latitudes. These are the regions from 40 to 60 degrees latitude in the northern and southern hemispheres. In Europe, temperate forests can be found from northwestern Europe to the Arctic Circle in Scandinavia. North American temperate forests include the temperate rainforests of the U.S. Pacific Northwest and Canada’s British Columbia. Otherwise, temperate forests remain in the eastern United States and portions of southeastern Canada. In Asia, temperate forests exist in western Russia, northeast China, and Japan. In the southern hemisphere, temperate forests cover much less territory. They can be found in southern Chile, Tasmania in Australia, and South Island in New Zealand. In general, temperate forests include both coniferous and deciduous species. (Coniferous trees produce cones and evergreen needles. Deciduous trees produce leaves that fall off seasonally.) Temperate rainforests are home mainly to coniferous (evergreen) species. In general, deciduous trees are those that produce leaves that change colors in the fall, drop to the ground, and sprout new leaves in the spring. Coniferous trees bear needles and cones and stay green all year round. However, not all trees or shrubs fall neatly into these categories. Some trees that grow needles and cones are actually deciduous trees. Some broadleaf trees and shrubs are neither coniferous nor deciduous. Examples include rhododendron and mountain laurel. Both are broadleaf evergreens that stay green all year long. They reproduce in the same manner as other angiosperms (flowering plants). Taiga is the Russian name for forest, although in southerly regions they are called boreal forests. The taiga represents the world’s largest connecting terrestrial biome, making up about 30 percent of all of Earth’s forests. In Asia, the taiga covers much of northern Russia and Siberia. Taiga forests are also found in northern Mongolia and Kazakhstan as well as on the Japanese island of Hokkaido. In Europe, taiga forests cover an area that includes northern Norway, Sweden, and Finland. In North America, boreal forests occupy most of the land area of the Canadian interior as well as a portion of Alaska. Spring and fall are barely noticeable in the taiga. Instead, there’s a short summer season that’s warm and humid. This is followed by a much longer season during which the closely packed coniferous trees are covered in frost and snow. If this season had a message on a sign, it might read, “Hostile to life. Enter at your own risk.” On the other hand, during the brief summer, the taiga is a haven for insects, which attract many species of birds. The birds build nests as they feast on the insects. A number of animal species are also adapted to life there. The snowshoe rabbit, for example, changes color from beige to white. Other year-round animals find ways to adapt to arctic temperatures. These include moles that tunnel under the snow, as well as bears, mice, badgers, wolverines, squirrels, and reindeer (in Eurasia).

· Grassland Biomes Two main types of grassland biomes exist: savannas and temperate grasslands. Species diversity, rainfall patterns, climate zones, and soil types distinguish these biomes from each other. Savannahs feature scattered individual trees separated by grasses. Africa is one example. The savanna covers nearly half the surface of central Africa, south of the Sahara. A key feature of the savanna is the alteration of dry and rainy seasons. During the rainy season, vegetation flourishes. Food can be gathered and stored. This is followed by a dry season, during which the land once again becomes parched and dry. Natural or human-set fires reduce the desiccated vegetation to ash. The ash revitalizes the soil with nutrients, and vegetation returns. Cattle and native species can graze the lush landscape. Other species can gather food. In any case, savannas like this are called climatic savannahs, as they depend on alternating seasons of wet and dry. Another kind of savanna is the derived savannah. This occurs when land is cleared to make room for farming or cattle ranching. Downed trees and shrubs are burned to produce ash. This ash creates viable soil—at least for a few seasons—after which new land must be cleared for the process to continue. Derived savannahs have overall negative environmental impact. For example, this is true of the Sahel that crosses Africa just south of the Sahara. Temperate grasslands include a rich mixture of perennial grasses (grasses that live more than two years) and flowering plants. These plants are called forbs. Temperate grasslands presently occupy about 25 percent of Earth’s land surfaces. The mixture of grasses and forbs produces some of the most fertile soils on the planet. As a result, most grassland has been converted for agricultural purposes (farming). The semi-arid climate of the temperate grasslands varies by region. That’s because grasslands extend over a wide range of latitudes. Imagine the distance from Kansas to northern regions of Alberta, Manitoba, and Saskatchewan in Canada. Over that range of area, summers may be warm or hot, depending on latitude. However, in much of this range, winter precipitation arrives as snow. So, on the plus side, the spring melt provides a steady source of moisture for the growing season. On the downside, rapid melting may result in serious flooding. In North America, grasslands include the high plains of the prairie states into Canada. In the United States, grasslands can be found in eastern Washington, parts of California, and in semi-arid regions of the Southwest. Globally, temperate grasslands can be found in Argentina, Uruguay, and the Veld region of South Africa. In Eurasia, the steppes are a type of grassland. The steppes can be found from the Ukraine west across central Russian to parts of Mongolia. The steppes played a major role in advancing humanity, as people there were the first to domesticate horses. The domestication of horses changed transportation and the conduct of wars forever. Typically, grassland fauna are low in diversity, especially as compared to tropical forests and savannas. In North America, native species included bison, pronghorn antelopes, and rodent herbivores such as pocket gophers, ground squirrels, and prairie dogs. Badgers and coyotes are still around as predators and scavengers.

To learn more about Earth’s major biomes, check out this video:

Ecological Challenges

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Let’s look at some of the ecological challenges facing the world. These issues are all related to climate change and global warming in various ways. As you learn about them, consider their origin and impact. Think about how they contribute to climate change and global warming.

Pollution

Pollution is the process of making land, water, or air unsafe for life. Pollution of the air, water, and soil is a problem for everyone. For example, in 2014 toxic chemicals were unintentionally spilled into the water supplies of nine counties and the city of Charleston in West Virginia. The culprit was a toxic chemical called 4-methylcyclohexane. The spill may have been an accident but it was still a catastrophe. The government issued a ban on the use of tap water for nine days, which barely made an impact on the ongoing problem. Several hundred people had to be treated in hospitals for chemical exposure over the following weeks. Tap water continued to have a peculiar, lingering licorice odor for some time afterward.

Pollution comes from many sources. For example, water pollution can come from oils spills, acid rain, and industrial and farm runoff. These issues also cause problems with soils. Farms that rely on petroleum-based fertilizers, pesticides, and herbicides, for instance, have destroyed organism-rich topsoil. Meanwhile, air pollution comes from emissions from internal combustion engines. Think about the brown clouds that are often seen over urban centers. (California has been a recent exception; in that state, regulatory action has made urban air more breathable.)

Waste Disposal

Across the globe, the overconsumption of resources has created a crisis associated with waste—garbage—disposal. Developed countries in particular produce an enormous amount of garbage. This garbage is dumped into the oceans or buried in landfills. The disposal of nuclear waste poses a tremendous health hazard. The radiation from nuclear waste dumps can remain toxic and lethal for centuries.

Waste disposal is one of our most serious environmental problems.

Here are examples of a few waste disposal dangers:

· Chemical spills pose danger to water supplies.

· Landfills and incinerators dump carcinogens and pollutants into the air. This increases the risks for cancer, asthma, and respiratory disorders.

· Landfills attract rats, flies, and other carriers of a variety of communicable diseases.

· Burning waste contributes to the number of greenhouse gases in the atmosphere. These gases promote global warming and climate change.

Let’s focus on that last item for a moment. According to one source, “Asia, Latin America, and Africa alone are to blame for about 40 percent of methane emissions every year. That 40 percent is equal to about 37 million metric tons of carbon dioxide.” Further, experts believe that industrialized nations produce considerably more waste than this. Specifically, “In the United States, each American produces an average of .75 tons of trash every year.” That’s the most waste per person per capita in the world. Europeans are estimated to dispose of about half a ton of trash annually. In Asia, an average person produces .2 tons of trash each year.

Pollution affects everyone, everywhere. Environmental problems in Asia can and do affect North America, Europe, and Africa. For this reason, cooperation among nations is needed to deal with the waste problem.

Consider, for example, Europe leads in the development of environmental technologies. In fact, about 60 percent of environmental discoveries and technologies originate in Europe. Thus, Europeans can play a major role in raising awareness and helping other nations to apply workable solutions. China and India are both high on the list of Asian countries with major pollution problems, including water and air pollution, deforestation, and the loss of biodiversity. Other countries can work with their governments to find workable solutions.

Urban Sprawl

Urban sprawl refers to the uncontrolled expansion of urban living areas. Urban sprawl means one thing in developed countries and quite another in developing or underdeveloped countries. In this lesson, we’ll focus on urban sprawl issues as they apply in the United States. The complex issues related to urbanization in the developing world will be considered in future lessons.

In developed countries, urban sprawl occurs when populations move from high-density cities into lower-density surrounding areas. The era of urban sprawl in the United States began during the period of economic prosperity following World War II. It was made possible in large part by the progressive reforms initiated under President Franklin Roosevelt’s “New Deal.” Labor unions were strong, and corporations embraced fair labor practices. There were plenty of good jobs with benefits. The G.I. Bill allowed a whole generation of young men to obtain a college education, and the future looked bright. Consumer demand soared. The philosophy of consumerism soared. The “American Dream” was linked to owning a home, sophisticated appliances, and the latest model of automobile. The rush to the suburbs became a stampede, which came at a serious cost. Let’s look more closely.

Increased Air Pollution

According to the Sierra Club, the typical annual commute from the suburbs to the workplace involves about eight workweeks of 55 hours each. That’s 440 unpaid hours sitting behind the wheel of an automobile. More driving leads to an increase in air pollution, in addition to health risks due to inhaling exhaust fumes and smog.

Overconsumption of Water

Urban sprawl means a larger ecological footprint for people. As people spread out and population density increases, water distribution problems arise. One of these problems is the result of a demand for water to landscaping. According to the EPA, about 30 percent of daily water in the United States is used outdoors. People water their lawns and golf courses, grow flowers and plants, and fill their outdoor pools. Review this site for more details: Understanding Your Own Water Use

Increased Risk of Obesity

According to the Ontario College of Family Physicians and the American Planning Association, life in the suburbs is associated with higher rates of obesity. This can partially be blamed on the consumption of processed foods and fast-food restaurants. However, experts also agree that obesity has risen due to overuse of automobiles for traveling even short distances.

In many places, people in the suburbs must drive to go anywhere. They spend too much time sitting in the car instead of walking where they need to go. In short, too little exercise can lead to an excess of weight on the body.

For more information on the relationship between urban sprawl and obesity, visit these sites:

· Effects of Urban Sprawl on Obesity

· Relationship Between Urban Sprawl and Physical Activity, Obesity, and Morbidity

Obesity is very problematic for people. It increases the risk of high blood pressure, cardiovascular disease, and diabetes, among other health concerns.

Loss of Wildlife Habitat

Wherever there’s urban sprawl, native wildlife suffers. Today, some 60 percent of native wildlife lives within metropolitan and suburban regions. Some of these species, such as black bears, whitetail deer, skunks, redtail hawks, starlings, and opossums, have adapted to populated environments. Even though these animals lived in suburban areas first, residents often view these species as annoyances. They look for ways to eliminate or minimize them.

For more detail on species endangered by urban sprawl, visit this site: Endangered by Sprawl

The list of threatened and endangered species is quite long. In Virginia alone, the U.S. Fish and Wildlife Service reports these numbers on their list of threatened or endangered species:

· Amphibians and reptiles: 7 (Most of them are species of sea turtles.)

· Birds: 4 (Example: The red-cockaded woodpecker is endangered because 97 percent of its habitat range has been destroyed.)

· Fishes: 8 (Example: The Atlantic sturgeon is now listed as engendered throughout the Chesapeake Bay due to overfishing and habitat destruction.)

· Mammals: 5 (Three of these species are bats coping with habitat destruction.)

· Mussels and other invertebrates: 31 (Again, in most cases the culprit is habitat destruction.)

· Plants: 17 (Another result of habitat destruction, especially in the Appalachian highlands.)

Total: 72. And that’s for just one state. Urban sprawl is endangering wildlife all across America.

Artists Speak: Characterizing Urban Sprawl

Sometimes we can better understand the dry statistics of topics like urban sprawl by listening to the voices of the arts, in this case, protest ballads. Recall that advances in technology may be at odds with cultural ideals. Below we’ll get a perspective on the suburbs from an article written by Angie Schmitt:

“The protest movements that have changed the world—for peace, civil rights or labor justice—have always had rallying songs that inspired devotees and informed the masses. The smart growth movement is no exception: sprawl and the general shortcomings of the American suburb have been a favorite theme among musicians ever since the invention of the cul-de-sac.

Rock music … literally teems with songs about loneliness, alienation, disaffection, conformity, overbearing authority, and general malaise as they relate to the modern suburban landscape. And as time has gone on, the cries have only gotten louder.

The first musical rattling of protest began nearly as soon as sprawl itself in the early 1960s. One of the first hits of this genre is Malvina Reynolds’s ‘Little Boxes,’ written in 1962 and made famous by Pete Seeger the following year. More recently, it was picked up by Showtime as the theme song for the suburban melodrama Weeds. Like many of its type, the song dwells on themes of conformity, material excess and spiritual poverty.

Little boxes on the hillside / Little boxes made of ticky tacky, Little boxes on the hillside / Little boxes all the same. There’s a green one and a pink one / And a blue one and a yellow one, And they’re all made out of ticky tacky / And they all look just the same.

Another classic is Joni Mitchell’s ‘Big Yellow Taxi,’ recorded in 1970. The song was inspired by a trip to Hawaii. When Mitchell looked out her hotel window, she saw a beautiful vista, marred by a large parking lot. The trip also . . . included a trip to the Honolulu Botanical Garden, which contained many rare and endangered tropical plants.

They took all the trees / Put ’em in a tree museum And they charged the people / A dollar and a half just to see ’em Don’t it always seem to go / That you don’t know what you’ve got till it’s gone They paved paradise / And put up a parking lot”

Depletion of the Ozone Layer

The ozone layer is found in Earth’s stratosphere. It provides a natural shield against harmful ultraviolet radiation (UV) from the sun. The ozone layer is composed of ozone gas. In fact, about 90 percent of all ozone in Earth’s atmosphere is found in this layer. (Most of the remaining 10 percent hovers near Earth’s surface as an atmospheric pollutant.) Ozone is important because it provides protection for the planet and allows species—including humans—to thrive. However, it’s also considered a toxic pollutant when it’s close to Earth. Ozone gas is one of the main components of urban smog.

To learn more about ozone, visit this site: Science: Ozone Basics

The stratosphere has that name because it’s stratified, or formed in layers. There are higher and lower layers. As one moves upward through the layers of the stratosphere, the atmosphere gets warmer. That’s because heat (energy) gets released as ozone interacts with ultraviolet (UV) radiation from the sun. These interactions essentially “devour” UV radiation.

Starting in the 1970s, scientists noticed the thinning of the ozone layer. This was especially noticeable over Antarctica, where an “ozone hole” was appearing. Note this isn’t an actual hole; rather the ozone at that location is vanishingly thin. In any case, as the ozone situation became known, scientists began to realize that human activity was the root of the problem. Experts identified the main eater of the ozone as chlorofluorocarbons (CFCs). CFCs are chemicals that combine molecules of carbon, chlorine, and fluorine. They’re used for many industrial purposes. However, they’re especially used for refrigerants, plastics production, and as propellants in aerosol cans. As these gases move upward in the stratosphere, they eat away at ozone in the stratosphere.

It’s clear that CFCs are potent greenhouse gases. International agreements such as the Kyoto Protocol seek to replace the use of CFCs with other substances, such as hydrofluorocarbons (HFCs). That has helped. The ozone layer is being gradually restored, and one kind of greenhouse gas has been sidelined. On the other hand, HFCs have also been identified as potent greenhouse gases. This raises the question: should plastics be abandoned worldwide? (This makes sense for many reasons, including waste management. Consider that the three “dead zones” in the Pacific Ocean are essentially enormous floating landfills, full of decayed plastics.)

By the way, before you spend time in a tanning bed, think twice. There are two kinds of ultraviolet light, UVB and UVA. UVB causes sunburn and can cause cancers such as basal cell and squamous cell carcinomas. Worse yet, UVB can penetrate the skin of organisms—both plants and animals—and cause permanent DNA damage. However, UVA, which is used in tanning beds, is far from risk-free. It’s now known that UVA can cause melanoma, a deadly skin cancer. UVA also leads to premature aging of the skin.

The ozone layer is linked to another ecological challenge, deforestation, which we’ll cover a little later. In simple terms, trees offset the effects of greenhouse gas emissions by serving as carbon sinks. That is, trees and plants are able to soak up carbon dioxide in the atmosphere while also replenishing oxygen. However, deforestation—the removal of trees—upsets this process. One way to fix the ozone problem is to plant more trees: as many as possible, in as many places as possible. This helps to check global greenhouse emissions and repair the ozone layer.

Acid Rain

Acid rain is produced by burning fuel that includes sulfur dioxide (SO2) and nitrogen oxides (NO, NO2). Acid rain may arrive as rain. However, it may also arrive in the form of snow, dew, hail, or fog. Acid rain (sometimes called acid precipitation) in any form is damaging to plants, animals, and humans.