Exam 15: The Evolution of Microbial Life

Food poisoning from Salmonella occurs because of ________.

Scenario Malaria is a disease caused by parasitic protists in the genus Plasmodium. The parasite is transmitted to humans by female Anopheles mosquitoes. The Plasmodium parasite feeds on human red blood cells, eventually destroying them. Humans infected with malaria can exhibit many symptoms. Depending on the severity of the infection, these can range from fever, chills, sweating, and headaches to anemia and kidney failure. Ultimately, malaria can result in death. However, if time and money permit, once a person is infected, they can be treated with different antimalarial drugs. Two commonly used drugs are artemisinin and quinine. In addition, one way to prevent the spread of malaria is to apply pesticides to treat areas with Anopheles mosquitoes. The National Malaria Eradication Program began work in 1947 with the goal of eliminating malaria from the southern United States. In 1947, 15,000 cases of malaria were reported nationwide. By 1950, only 2,000 cases were reported, and by 1951, malaria was considered eradicated from the United States. Today, the disease is most common in Africa and South America, two continents that are highly impoverished. About one million people die from malaria every year, many of them children. In Africa, it is estimated that one in every five childhood deaths is due to malaria. -Suppose production of the pesticides used to treat malaria is halted because the Environmental Protection Agency (EPA)has found that they are causing too much environmental damage to warrant continued use. In turn, this drives up the prices of artemisinin and quinine since they are now in higher demand. How might this affect those that live in South America and Africa?

Why is RNA thought to have been the first genetic material?

Which statement is FALSE?

Scenario Endotoxins are commonly found in the air, both inside and outside our homes. These "air endotoxins" can come from sources that include house dust mites, agricultural and industrial dust, and dust from indoor pets. Air endotoxins are typically found in low amounts, but production of them can increase dramatically under specific environmental conditions such as dampness, mold, and sewage. Many scientific studies have been conducted investigating possible links between indoor endotoxin levels and asthma, chronic bronchitis, and other upper respiratory diseases. Interestingly, some studies have found positive correlations between indoor endotoxin exposure and severity of some of these diseases while other studies have suggested that some air endotoxin exposure can actually decrease the risk of developing asthma in children. Additionally, data suggest that industrial workers who are exposed to endotoxins in the air can develop irreversible lung damage. In 2005, Hurricane Katrina devastated the eastern coastline of the United States. The state of Louisiana, and in particular the city of New Orleans, experienced tragic loss of human life and homes due to the failure of the levee system. Intense flooding destroyed homes and created severe exposure to wet, moldy surfaces. At that time there were no regulations in existence on the amount of exposure that individuals should have to air endotoxins. Scientists from the Natural Resources Defense Council who wanted to determine if endotoxin levels had risen in New Orleans conducted tests across 12 outdoor areas, 9 of which had been significantly flooded while the other 3 were less affected. Two indoor areas were also sampled for endotoxin levels. No significant differences were found in endotoxin levels between the flooded and non-flooded areas or between the indoor and outdoor areas. However, a limited number of samples were collected, and they were taken after a recent dry spell. Endotoxin levels at all sites were found to be higher than national average levels but were lower than levels typically associated with long-term changes in lung function. -What is an implication of the fact that tests were conducted after a period of dry weather?

What kind of protist is shown in the figure?

Scenario Endotoxins are commonly found in the air, both inside and outside our homes. These "air endotoxins" can come from sources that include house dust mites, agricultural and industrial dust, and dust from indoor pets. Air endotoxins are typically found in low amounts, but production of them can increase dramatically under specific environmental conditions such as dampness, mold, and sewage. Many scientific studies have been conducted investigating possible links between indoor endotoxin levels and asthma, chronic bronchitis, and other upper respiratory diseases. Interestingly, some studies have found positive correlations between indoor endotoxin exposure and severity of some of these diseases while other studies have suggested that some air endotoxin exposure can actually decrease the risk of developing asthma in children. Additionally, data suggest that industrial workers who are exposed to endotoxins in the air can develop irreversible lung damage. In 2005, Hurricane Katrina devastated the eastern coastline of the United States. The state of Louisiana, and in particular the city of New Orleans, experienced tragic loss of human life and homes due to the failure of the levee system. Intense flooding destroyed homes and created severe exposure to wet, moldy surfaces. At that time there were no regulations in existence on the amount of exposure that individuals should have to air endotoxins. Scientists from the Natural Resources Defense Council who wanted to determine if endotoxin levels had risen in New Orleans conducted tests across 12 outdoor areas, 9 of which had been significantly flooded while the other 3 were less affected. Two indoor areas were also sampled for endotoxin levels. No significant differences were found in endotoxin levels between the flooded and non-flooded areas or between the indoor and outdoor areas. However, a limited number of samples were collected, and they were taken after a recent dry spell. Endotoxin levels at all sites were found to be higher than national average levels but were lower than levels typically associated with long-term changes in lung function. -What is a potential benefit of testing indoor and outdoor sites as well as sites with heavy flooding and light flooding?

The prokaryotic group that tends to inhabit extreme environments belongs to ________.

Which protozoan group has primarily been identified through fossils?

In the soil, some ________ help to decompose dead organisms and other waste materials, returning vital chemical elements such as nitrogen to the environment.

What are the two classes of poisons produced by pathogenic bacteria?

Scientists hypothesize that disrupting our ________ communities may increase our susceptibility to infectious diseases, predispose us to certain cancers, and contribute to conditions such as asthma and other allergies, irritable bowel syndrome, Crohn's disease, and autism.

Which groups of organisms colonized land during the Paleozoic era approximately 500 million years ago?

In the associated image, the aquatic organism moves using flagella. It is parasitic and can colonize and reproduce in the human intestine. What type of organism could this be?

Land was first colonized about ________ years ago.

Based on fossil evidence, eukaryotes evolved about ________ years ago.

Spherical bacteria that occur in clusters are ________.

Trichomonas vaginalis is a protozoan that feeds on white blood cells and bacteria living on the cells lining the female human vagina, thereby creating a common sexually transmitted disease often known as "trich." The feeding mechanism of this protozoan makes it a ________.

The absence of ________ in the primitive atmosphere was essential to the origin of life on Earth.

From what can pre-cells spontaneously form?