Vocabulary: biodiversity, monoculture, greenhouse effect, endangered species, exotic/invasive species, acid precipitation, global warming, CFCs, SEQR, biodegradable
Due to evolution, there is a great number of different organisms which fill many different roles in ecosystems. The number of different organisms in an ecosystem is called biodiversity. Increased biodiversity increases the stability of the ecosystem. Biodiversity also ensures the availability of diverse genetic material that may lead to future discoveries with significant value to humans. As diversity is lost, potential sources of these materials for these discoveries may be lost with it. A great diversity of species provides for variations which increase the chance that at least some living things will survive in the face of large changes in the environment.
As a result of evolutionary processes, there is a diversity of organisms and a diversity of roles in ecosystems. Biodiversity refers to the differences in living things in an ecosystem. Increased biodiversity increases the stability of the ecosystem as it provides for more genetic variation among species. A great diversity of species increases the chance that at least some living things will survive in the face of large changes in the environment.
The Need for Biodiversity
Human Influences on Biodiversity
When humans alter ecosystems either by removing specific organisms, serious consequences may result. Human beings are part of the Earth’s ecosystems. Human activities can, deliberately or accidentally, change the equilibrium in ecosystems. Humans are destroying other species as a result of population growth, consumption, and technology. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is especially threatening current global biodiversity.
An example of a human activity which has decreased biodiversity is the use of monoculture in modern agricultural practices. Monoculture involves planting one variety of a species over a huge area. This leaves this area more vulnerable to predation or disease and the loss of many or all species.
Uses of Biodiversity
In addition to the aesthetic beauty added to the world by many different organisms, biodiversity also ensures the availability of a rich variety of genetic material that may lead to future agricultural or medical discoveries with significant value to humankind. As diversity is lost, potential sources of these materials may be lost with it.
The Earth has limited resources to support the organisms that live on it. Increasing human population numbers are putting great pressure on many of these limited resources and deplete those resources which can not be renewed. Many different natural processes occur within those ecosystems influencing humans. Some of these processes include atmospheric quality. soil generation and conservation, energy flow, the water cycle, waste removal and recycling. Human activities are altering the equilibrium involved in these natural processes and cycles. If these changes due to human activities are not addressed, the stability of the world's ecosystems may irreversibly affected.
Human activities which have harmed ecosystems have resulted in a loss of diversity in both living things and the nonliving environment. Examples of these changes include land use, the cutting of vast areas of forest, and pollution of the soil, air, and water. Another way humans have changed ecosystems in a harmful way is by adding or removing specific organisms to these ecosystems Our ever increasing demand for energy has impacted ecosystems negatively as well. Many environmental risks are associated with our use of fossil and nuclear fuels.
Many factors associated with human populations have influenced environmental quality. These include population growth and distribution on our planet, our use of resources, the ability of technology to solve environmental problems, as well as the role of economic, political, ethical, and cultural views in solving these problems.
Individual choices and the actions of society can contribute to the improvement of our environmental problems. Our choices which must include an assessment of the risks, costs, benefits, and trade-offs of new technologies and continued human expansion. All changes and proposed improvements need to consider both the human and environmental impact of the change.
The Earth has limited to resources to support populations of humans and other organisms. Our ever increasing human numbers is depleting many of our planet's resources and placing severe stress on the natural processes that renew many of our resources.
Natural ecosystems are involved in a wide variety of natural processes influencing humans and other organisms. The activities of humans in the environment are changing many of these natural processes in a harmful fashion. Some of these natural processes and a brief description of a human influence on these processes is indicated in the table which follows.
Human Influence on Some Ecosystem Processes
Generation of Soils Agricultural practices have exposed soil to the weather resulting in great loss of topsoil. Control of the Water Cycle The cutting of forests and other human activities have allowed increased uncontrolled runoff leading to increased erosion and flooding. Removal of Wastes Untreated sewage wastes and runoff from farms and feedlots have led to increased water pollution. Energy Flow Some industries and nuclear plants have added thermal pollution to the environment. The release of some gases from the burning of fossil fuels may be slowly increasing the Earth's temperature.
Nutrient Recycling The use of packaging material which does not break down, burning of refuse, and the placing of materials in landfills prevents the return of some useful materials to the environment.
Some Detrimental Human Activities
Humans are part of the Earth's ecosystem. Human activities can either deliberately or inadvertently alter the balance of an ecosystem. This destruction of habitat, whether accidental or intentional, is threatening the stability of the planet's ecosystems. If these human influences are not addressed, the stability of many ecosystems may be irreversibly affected. Some of the ways that humans damage and destroy ecosystems are indicated in the table below.
Some Ways Humans Adversely Influence Ecosystems
Effect on Ecosystems
Population growth Our increasing numbers are using excessive amounts of the Earth's limited resources. Overconsumption Industrialized societies are using more resources per person from our planet than people from poor nations. Advancing Technologies Often we introduce technology without knowing how it will influence the environment Direct Harvesting This has resulted in a large loss of rainforest and the many products associated with its biodiversity. Pollution Land, air, water, and nuclear pollution have had many adverse influences on ecosystems. Atmospheric Changes These include the addition of Greenhouse gases mostly due to the burning of fossil fuels and depletion of our stratospheric ozone layer.
Other pollutants also have negative effects on living things.
Human technologies which degrade the environment result in a loss of diversity in the living and nonliving environment. Biodiversity refers to the differences in living things in an ecosystem. Many of our technologies and resource use practices have resulted in an irreversible loss of biodiversity.
Some examples of human activities which have negatively influenced other organisms include our land use practices and pollution. Excessive land use decreases the space and resources available to other species on the planet. Air, soil, and water pollution changes the composition of these environmental resources, making them harmful and unusable for other species and sometimes ourselves.
Endangered species are those species which are threatened with destruction due to habitat destruction or other factors. Animals which were once endangered but are presently successfully reproducing and increasing their numbers are the bison, gray wolves and egrets. Other endangered animals which are currently responding to conservation efforts and beginning to make a comeback are the whooping crane, bald eagle, and peregrine falcon. Even with these successes, the future of many endangered species remains in doubt.
The importation of some organisms have caused problems for native organisms. Organisms which are imported into an area from another region are called exotic species. Many examples of this are found world-wide. Some common examples of exotic species having negative effects would include the rabbits and deer which were imported into Australia. These exotic species won the competition with many native herbivorous marsupials and became nuisance species. The starling was brought into the United States from Europe. The starling has out competed many of our native songbirds. We also have alien invasive species which have caused problems in New York State. These include the plants such as the Water Chestnut, Eurasian Water milfoil, and Purple Loosestrife and animals such as the Alewife and Zebra Mussel.
The Purple Loosestrife
Purple loosestrife is a plant native to Europe. It was brought to North America in the early 1800's by immigrants who valued its beautiful purple flowers. It is now a serious pest of wetlands. Once purple loosestrife enters a wetland, it takes over. Common native wetland plants, such as cattails, cannot compete with purple loosestrife. Once these native plants are choked out, the wildlife that depends on them for food and shelter are also eliminated.
Use of Fossil Fuels
Fossil fuels are becoming rapidly depleted. The use of these fuels are adding to out air pollution problems. The search and demand for additional fossil fuel resources also impact ecosystems in a negative way. Industrialization has brought an increased demand for and use of energy.
One of the ways the increased burning of fossil fuels has had a harmful influence of the environment is by causing an increased incidence of acid precipitation.
How does Acid Precipitation occur?
Most acid rain influencing New York State is caused by sulfur dioxide and nitrogen dioxide pollution from the burning of fossil fuels in the Western and Midwestern United States. These gases combine with water vapor in the atmosphere and fall back to the earth over New York and the Eastern United States as acid precipitation.
Some Problems Associated With Acid Precipitation
- Destruction of limestone and marble monuments due to increased chemical weathering
- Acidification of aquatic ecosystems destroying the life in them
- Damage forests and other plants in a variety of ways
Our increased burning of fossil fuels and the release of excess carbon dioxide to the atmosphere associated with their combustion is also contributing to the Greenhouse Effect or global warming. It is believed the increase in level of carbon dioxide and some other gases is not allowing much infrared or heat radiation to escape the planet into outer space. This is causing our planet to slowly warm The graphs in the table below show the link between increasing earth carbon dioxide levels and the increase in global average temperatures.
Global Temperature and Carbon Dioxide Levels
Some Consequences of Global Warming
- Rising sea levels and coastal flooding
- Changed precipitation patterns which may result in droughts in some regions and increased levels of crop failure
- An increase in insect borne diseases in temperate regions such as New York State as milder winters fail to kill the disease carrying insects. (The increase in the incidence of West Nile virus may be an example of this.)
CFC's (chloroflurocarbons) are very active chemicals associated with certain human manufacturing processes and products. This CFC pollution from refrigerants and plastics are destroying our thin ozone shield high up in our atmosphere or in the stratosphere. This layer of ozone normally shields us from excessive incoming ultraviolet radiation. Some consequences of this ever increasing ozone depletion appear to be an increased incidence of skin cancers and cataracts in the human population.
While nuclear energy avoids many of the pollution drawbacks associated with the increased burning of fossil fuels, there are many risks associated with the use of nuclear fuels for energy. Environmental dangers exist in reference to obtaining, using, and storing the wastes from these fuels. Many of the waste products of used nuclear fuel stay in the environment for thousands of years and release radiation which is harmful to humans or other living things. Additionally, the water used to cool many nuclear reactors must be released eventually to the environment. The thermal pollution associated with this released heat into the water is potentially dangerous to the aquatic life in the area where this hot water is released.
Other Factors Influencing Environmental Quality
Many different factors besides industry and resource use have influences on environmental quality. Some factors include population growth and distribution, resource use, the capacity of technology to solve environmental problems, as well as economic, cultural, political, and ethical views.
Some Examples of Political or Cultural Views Influencing Environmental Quality
- Wealthy people in the developed world tend to have fewer children.
- Some countries like China have laws concerning the number of children a couple may have without penalty.
- In some countries such as many in Latin America, families tend to be larger as birth control violates religious and societal norms.
- In some poor cultures in third world countries, having many children is seen as a means of having economic security in old age.
Through a greater awareness of ecological principles and application of these principles to our natural environment, humans can help assure there will be suitable environments for succeeding generations of life on our planet.
Individuals in our societies will always have to make decisions on proposals involving the introduction of new technologies. Individuals in these societies need to make decisions which will assess the risks, benefits, trade-offs, and costs of these new technologies. The economic rewards of these technologies must be properly balanced with any adverse consequences these new technologies may have on the environment. It may be impossible to completely assess the consequences of introducing a new technology, but critical questions in reference to its introduction must be asked.
While the overall impact of humans on the planet's ecosystems have been negative, humans have done many things to improve the overall quality for living things in ecosystems we have damaged or destroyed. Activities having possible adverse effects on the environment in New York State are subject to review by SEQR (State Environmental Quality Review Act). Some other ways in which humans have attempted to minimize negative impacts or improve the ecosystems we are all a part of are listed in the table which follows.
Some Positive Influences of Humans on the Ecosystem
- Sustaining endangered species by using habitat protection methods such as wildlife refuges and national parks.
- Passing wildlife management laws, such as game laws and catch restrictions.
- Adding lime to Adirondack lakes in an effort to neutralize their
acid pollution so the original living things in these lakes can be reintroduced.
- Design new products which meet basic needs without generating pollution.
- Inspection of all materials before entering the country to prevent pest introduction.
- Increased use of biodegradable packaging materials which will recycle themselves quickly to the environment.
- Use fuels which contain less pollutants, such as low sulfur coal and oil.
- Remove pollutants by using such devices as afterburners or catalytic converters before they enter the air.
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