Exam 15: The Evolution of Microbial Life

Bacilli are ________ prokaryotes.

Which prokaryotic group is most closely related to eukaryotes?

You discover a unicellular organism that moves by what appear to be pseudopodia. You conclude that this organism could be ________.

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 addition to methodology would be most beneficial to the study?

According to this evolutionary tree, the archaea and eukaryotes last shared a common ancestor ________.

________ is an example of bioremediation.

Prokaryotes reproduce by means of ________.

Which organisms would likely be the most difficult to kill if you were you to can your own food?

What was the third stage of the process that led to the abiotic origin of life?

________ include cells that can function either independently or as a single unit.

By the end of the ________, all major body plans and major groups of organisms had evolved.

Flagellates, amoebas, apicomplexans, and ciliates are all what type of protist?

Variation among pre-cells was due to ________.

________ are responsible for toxic red tides.

Eukaryotes arose about ________ years after the first prokaryotes.

Yersinia pestis is a strain of bacteria that caused the "black death" plague that killed more than 50 million people in the 14th century. The bacteria spread quickly and easily through the air and from person to person. Yersinia pestis might be studied by scientists interested in ________.

A protist with a shell made of silica is most likely a(n)________.

Some aquatic invertebrates such as insects and snails feed on biofilms. Scientists that study metal-contaminated streams have documented that some biofilms in stream environments absorb zinc from stream water during daylight hours and release the zinc into the stream during the night. If the scientists were to test exposure of the invertebrates to zinc, what might they hypothesize?

Some aquatic invertebrates such as insects and snails feed on biofilms. Scientists that study metal-contaminated streams have documented that some biofilms in stream environments absorb zinc from stream water during daylight hours and release the zinc into the stream during the night. What might the scientists hypothesize about zinc concentration in the stream?