Back To CourseDSST Environmental Science: Study Guide & Test Prep
18 chapters | 177 lessons
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Margaret has taught many Biology and Environmental Science courses and has Master's degrees in Environmental Science and Education.
What do you think is the main goal of agriculture? Agriculture was developed to produce crops and livestock for human consumption. As the human population increases, the amount of food produced is very important. Unfortunately, there are other organisms out there that want to consume the crops that are meant for humans. It is estimated that nearly 37% of all crops produced in the United States each year are destroyed by agricultural pests, which results in an economic loss of around $122 billion a year.
Due to this high loss in food production, pesticides are often used to try to combat the problem. Pesticides are chemicals that kill or manage the population of pests. There are many different types of pesticides on the market today, but the most common are herbicides and insecticides, which kill or manage unwanted plants and insects. The damage caused by agricultural pests is a global problem, and over the past half-century, the amount of pesticides used has increased fourfold. Over the years, the widespread use of pesticides has had several benefits and also caused many problems.
The benefits of pesticides include increased food production, increased profits for farmers and the prevention of diseases. Although pests consume or harm a large portion of agricultural crops, without the use of pesticides, it is likely that they would consume a higher percentage.
Due to the use of pesticides, it is possible to combat pests and produce larger quantities of food. By producing more crops, farmers are also able to increase profits by having more produce to sell. Pesticides also increase farm profits by helping the farmer save money on labor costs. Using pesticides reduces the amount of time required to manually remove weeds and pests from fields.
In addition to saving crops and livestock, pesticides have also had direct benefits to human health. It is estimated that since 1945, the use of pesticides has prevented the deaths of around seven million people by killing pests that carry or transmit diseases. Malaria, which is transmitted by infected mosquitoes, is one of the most commonly known and deadly diseases that has decreased in prevalence due to the use of pesticides. Other diseases that were minimized due to the use of pesticides include the bubonic plague, which is carried by rat fleas, and typhus, which is transmitted by both fleas and body lice.
Although there are benefits to the use of pesticides, there have also been many problems associated with their use. When pesticides are used, they do not always stay in the location where they are applied. They are mobile in the environment and often move through water, air and soil. The problem with pesticide mobility is that when they travel, the pesticides come in contact with other organisms and can cause harm.
Pesticides have also been shown to disrupt the balance of an ecosystem. In many situations, when a pesticide is used, it also kills non-pest organisms. This can drastically alter the natural balance of the ecosystem. By removing non-pest organisms, the environment can be changed to favor the pest. In addition to causing harm to wildlife, pesticides that travel from their original location are known to cause harm to humans. Human exposure to pesticides has caused poisonings, the development of cancer and the deaths of between 20,000 and 40,000 people worldwide each year.
Another major problem associated with pesticide use is bioaccumulation and biological magnification. Bioaccumulation is when a substance builds up in the body because the body does not have the proper mechanisms to remove it. Many synthetic pesticides are not able to be broken down. Once they enter the body of an organism, they are permanently stored in the body tissue.
The pesticides that accumulate in an organism's body can cause harm to the organism or can be passed on to a predator. Due to the fact that the pesticides are integrated into the tissue of an organism, when it is consumed by a predator, the pesticides are transferred. As the predator consumes more exposed individuals, the concentration of pesticides in their own body will increase.
Organisms that are higher in the food chain will have increased concentrations of pesticides because they consumed many lower level organisms and received the pesticides stored in those organisms. Biological magnification, also known as biomagnification, is the term used to describe when chemicals, in this case pesticides, increase in concentration with each level of the food chain. A famous example of biomagnification is with the pesticide known as DDT.
Starting in the 1950s, this pesticide was used to kill mosquitoes and sprayed on crops to kill pests. DDT got into the water supply and was integrated into the bodies of zooplankton, which were then consumed by small fish and then larger fish. Eventually, the larger fish were eaten by predatory birds, and due to the biomagnification of the pesticide, the birds were killed by the large concentration of pesticides that accumulated in their bodies. This led to the near extinction of several predatory birds, including the bald eagle and peregrine falcon.
Genetic resistance is one problem associated with pesticide use that has become more of an issue over the years. Genetic resistance is when a species' genetic makeup changes over generations and results in the species becoming resistant to something that used to cause it harm. In relation to pesticide use, genetic resistance has occurred in many pests over the years, especially insects.
When a pesticide is applied to crops, most of the pests are killed, but it is possible that some individuals survive because they possess the ability to metabolize or detoxify the pesticide. The pests that survive continue to breed and pass along their genetic information, which possesses their resistance to the pesticide. Over generations, the number of individuals with resistance to the pesticide will increase because they are the only ones that can survive and reproduce. Eventually, the entire population of pests will be resistant to the pesticide, and it will be rendered useless. As a result, farmers must use higher concentrations of the pesticide or try new, potentially more toxic chemicals.
Now, let's review the use of pesticides, which are chemicals that kill or manage the population of pests. Pesticides are widely used in the agricultural field to deal with pests. Over the years, the amount of pesticides used worldwide has increased significantly. There are several benefits to the use of pesticides, such as increased food production, increased profits for farmers and the prevention of diseases.
Although pesticides are widely used and the benefits are helpful to the human population, there are many problems associated with pesticides. One problem with pesticides is that they are mobile in the environment and can therefore travel through air, water and soil to cause harm to the environment, animals and humans.
Pesticides are also known to disrupt the balance of an ecosystem by causing harm to organisms that are not pests. The pesticides can kill beneficial organisms and change the dynamic of the ecosystem. Another major problem associated with the use of pesticides is development of bioaccumulation and biological magnification.
Bioaccumulation is when a substance builds up in the body because the body does not have the proper mechanisms to remove it. Pesticides build up in the body of organisms and are later passed to their predators when consumed. This leads to biological magnification, which is when chemicals, in this case pesticides, increase in concentration with each level of the food chain.
One of the most major problems associated with pesticide use is the fact that pesticides become less effective over time as species develop genetic resistance, which is when a species' genetic makeup changes over generations and results in the species becoming resistant to something that used to cause it harm.
Although pesticides have made it possible to produce more food and feed the growing human population, after examining the problems associated with pesticide use, it is evident that something needs to change. Due to the severity of the problems associated with pesticide use, both scientists and farmers need to work together to develop safer methods of pest control to ensure the production of enough food.
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Back To CourseDSST Environmental Science: Study Guide & Test Prep
18 chapters | 177 lessons