InQuizitive: Chapter 15: Bacteria and Archaea: Navel Gazing *ANSWERS*

Microbes rely on specialized structures found only in prokaryotes to perform specific tasks or to give them an advantage over competing microbes. For each of the following mutations, predict the effect the mutation would have on the affected microbes.

(Loss of flagella) The affected microbes would be unable to move efficiently through liquid. (Loss of pili) The affected microbes would no longer be able to adhere to surfaces. (Loss of capsule) The affected microbes would be unable to protect themselves efficiently.

How might each of the activities in the belly button microbiome project fit into a citizen science paradigm?

- Local schoolchildren collect and mail in soil samples to allow researchers to explore the larger environment for comparison to regional variations in naval biomes. - Individuals explore the microbiome database and record when they find genetic sequences that are tied to different prokaryotes. - Members of a university class complete naval swabs to add their belly button biomes to the data set.

Some biologists explore the possibility of life on other worlds. Archaeans are of particular interest in this regard because of their ability to survive in extreme conditions. Which archaeans would be of interest if you wanted to understand potential life on planets with different conditions?

Anaerobe - a planet with anoxic conditions Halophile - a planet with bodies of water that are hypersaline—very salty Thermophile - a planet that orbits near a star and is extremely hot Acidophile - a planet with a gaseous atmosphere of very low pH

While studying an abandoned chemical factory, you discover what appears to be a slimy layer of microbial growth in one of the pools used to collect industrial waste. You know for a fact that the pH of the pool is too acidic for most living organisms. If the slimy growth is in fact alive, what kind of organism would it most likely be?

Archaean

Microbiologists are constantly looking for new microbes in the environment. For each of the following environments, predict whether you would expect to find archaeans, bacteria, or both.

Archaeans - at the edge of a geyser - in a very salty lake Bacteria - N/A Both - in the gut of a newly discovered mammal - in a sample of soil

Although archaeans and bacteria can both live in the human belly button, there are differences between them. Which of the following is a key difference between archaeans and bacteria?

Archaeans are found in extreme environments while bacteria are not.

When Rob Dunn began studying the organisms found in human belly buttons, he discovered many different types of bacteria and even a couple of archaeans. Determine if each statement below refers to bacteria, archaeans, both, or neither.

Archaeans: - often found in extreme environments - most closely related to eukaryotes Bacteria: - commonly found on and in humans Both: - are examples of prokaryotes Neither: - contain a nucleus

Drag each described organism to the domain on the tree where it would likely be located.

Bacteria (a single-celled prokaryote found in a garden) Archaea (a single-celled prokaryote found in a geyser) Eukarya (a single-celled, green alga found in the ocean)

You have been asked by a colleague to determine if a newly developed compound is harmful to living organisms. If species is not a consideration, what would be the best model organism to use, and why?

Bacteria, because they grow rapidly and are easily handled.

Prokaryotes can reproduce rapidly to take advantage of an available resource that they are adapted to use. For example, some bacteria have unique processes that allow them to consume petroleum. If oil is available and these bacteria come across it, which mechanism will they use?

Binary Fission

Although most of the organisms researchers have found in the belly button are bacteria, they were able to identify two archaean species on one "particularly fragrant" individual as well. Which of the following statements accurately describe archaeans?

CORRECT ANSWERS - Archaeans are prokaryotic. - Archaeans are found in extreme environments. INCORRECT ANSWERS - Archaeans have mitochondria. - Archaeans are more closely related to bacteria than eukaryotes.

Microbes often contain specialized structures that allow them to survive their environment or gain an advantage over their competitors. Examine the figure below depicting the steps required to develop a biofilm. Which of the following specialized structures would likely be involved?

CORRECT ANSWERS - Flagellum - Pili INCORRECT ANSWERS - Capsule

Which of the following statements describe how microbes can benefit other organisms in their environment?

CORRECT ANSWERS - Microbes use nitrogen fixation to supply plants with ammonia or nitrate. - Microbes cycle nutrients back into the environment. - Microbes use fermentation to produce alcohols and acids. INCORRECT ANSWERS - Microbes use quorum sensing to detect the arrival of harmful bacteria. - Methanogens remove methane from the atmosphere, thereby reducing global warming.

You overhear someone stating that prokaryotes, such as bacteria and archaeans, are too simple to compete with eukaryotes in a natural environment. What examples could you use to convince this person that prokaryotes are well-suited to compete with eukaryotes in nature?

CORRECT ANSWERS - The simplicity of prokaryotes can be an advantage since they require less energy to survive than eukaryotes. - Rapid growth by prokaryotes allows these organisms to quickly adapt to most environments. INCORRECT ANSWERS - Due to their small size, prokaryotes have little, if any, effect on eukaryotes. - Rapid growth by prokaryotes quickly depletes an environment of nutrients.

Rob Dunn noticed that the prokaryotes his team discovered in the belly buttons of volunteers were able to quickly take over an area due to their rapid growth rate. Which of the following statements explain why prokaryotes are able to divide so fast?

CORRECT ANSWERS - They lack organelles. - They are smaller. INCORRECT ANSWERS - They have faster metabolisms. - They synthesize DNA faster.

The discovery that our belly buttons harbor many different microbes was made possible through citizen science. What qualities are required to participate in citizen science?

CORRECT ANSWERS - a willingness to volunteer time to the science project - an interest in furthering our understanding of the world INCORRECT ANSWERS - a willingness to travel to where the project is being conducted - an advanced degree in science

Citizen science projects like the study of microflora found in the human belly button are becoming increasingly more popular. What are some of the benefits of participating in citizen science?

CORRECT ANSWERS - adding to established scientific knowledge - learning something new - feeling a sense of accomplishment INCORRECT ANSWERS - fame - monetary gain

Researchers working with Rob Dunn set out to collect and identify microbes found in belly buttons. When the researchers began identifying these microbes, they found that the microbes represented a wide range of metabolic activities. For example, one microbe might be able to break down sugars found in the belly button for energy, but only in the absence of oxygen. What terms would you use to describe this microbe?

CORRECT ANSWERS - anaerobe - fermenter INCORRECT ANSWERS - aerobe - autotroph

Rob Dunn and Noah Fierer set out to identify microbes that could be isolated from the belly buttons of volunteers. If you were to conduct a similar experiment to identify organisms present in the highly acidic runoff water from acid mines (pH of around 3 or 4), which types of microbes would you expect to find?

CORRECT ANSWERS - archaeans INCORRECT ANSWERS - bacteria - fungi

Many citizen science projects like the one to collect and analyze belly button microbes allow citizens to participate in science projects across the globe. Which of the following are examples of citizen science projects?

CORRECT ANSWERS - breeding bird surveys in which locals count the number of birds in their area - stormwater analysis by students of their local water systems - BioBlitz events in which locals help catalog the biodiversity of an area INCORRECT ANSWERS - donating to a local zoo - earning an undergraduate biology degree

Both Rob Dunn and Noah Fierer have conducted science projects that have revealed that archaeans can be found in many different environments. Which of the following are environments in which archaeans have been found?

CORRECT ANSWERS - human skin - hot springs - salt lakes INCORRECT ANSWERS - meteorites

Microbes have adapted to survive in many different environment and conditions. In which of the following environments would you likely find a photoautotroph?

CORRECT ANSWERS - in the upper layers of the ocean - in "pond scum" floating on the surface of a marsh INCORRECT ANSWERS - on the surface of an underground lake - in the bottom of the ocean

Despite prokaryotic microbes being invisible to the naked eye, Rob Dunn and his team understood that they were likely to find such microbes on their test subjects since prokaryotic microbes can reproduce rapidly and thrive on the human body. What other advantages do prokaryotes have as a result of their rapid reproduction?

CORRECT ANSWERS - the ability to become highly abundant in most ecosystems - the ability to quickly evolve to survive harsh environments INCORRECT ANSWERS - the ability to become one of the largest organisms in an ecosystem - the ability to become the dominant organism in an ecosystem

The SETI@home project, an ongoing project since 1999, is a citizen science project in which citizens use a screensaver on their computer to analyze radio telescope data collected by the Arecibo Observatory in Puerto Rico. The signals collected by the telescope are broken into smaller packets of information and sent to participant computers. The participant computers analyze the information while the computer is not being actively used and send the processed data back to researchers at the University of California, Berkeley. What parts of this project make it "citizen science"?

CORRECT ANSWERS - the fact that participants volunteer computer time to process data - the fact that anyone can join and contribute to the project INCORRECT ANSWERS - the fact that the project gives the participants access to data from a radio telescope - the fact that the project is overseen by scientists

As part of a research team assigned to identify possible archaeans present in a soil sample, you decide to recreate some of the conditions in which archaeans are found in hopes of encouraging their growth in the lab. What could you add to your cultures to encourage archaean growth?

CORRECT ANSWERS - vinegar - very hot water - table salt INCORRECT ANSWERS - sugar - fertilizer

Some microbes contain structures that are unique to prokaryotes. On the image below, which structure provides additional protection for the microbe?

Capsule

The citizen science project in which Rob Dunn and his group attempted to identify microbes found in belly buttons asked people to volunteer samples to be analyzed. Which of the following images depict citizens participating in citizen science?

Click on Image 1: Citizen scientists from the Republic... Image 2: A citizen scientist in North America...

Identify each of the organisms shown in the image below as prokaryote or eukaryote.

Domain Bacteria (prokaryote) Domain Archaea (prokaryote) Kingdom Plantae (eukaryote) Protists (eukaryote) Kingdom Animalia (eukaryote) Kingdom Fungi (eukaryote)

Bacteria use hairlike projections called pili to swim through liquid environments.

FALSE

Differentiate between bacteria and archaeans, and explain why they are together referred to as prokaryotes. Prokaryotes such as the ones Rob Dunn found exist in nearly every environment on the planet. Examine the image and then determine whether the following statement is true or false. Since bacteria and archaeans are both prokaryotic, they are usually found in the same environments.

FALSE

During a study session, one of your classmates explains that prokaryotes are more adaptable to new environments because they are believed to have been one of the first organisms to have evolved on the planet. Is your classmate's statement true or false?

FALSE

Rob Dunn and Noah Fierer both conducted experiments in which they looked for microbes found in the belly buttons of volunteers. During their search, they expected to find examples of bacteria and fungi, but were surprised to also find archaeans. Evaluate whether the following statement is true or false: Archaeans are prokaryotic and therefore are more closely related to bacteria than fungi (which are eukaryotes).

FALSE

Rob Dunn started the belly button project to see what microbes might be present on people as part of their microbiome. He expected to find bacteria and fungi in the belly buttons of his volunteers but was unsure if he would also find archaeans. Consider Dunn's work, and determine whether the following statement is true or false.Archaeans are found only in extreme environments.

FALSE

Rob Dunn's group of researchers found a variety of microbes living in belly buttons. These microbes can be classified by their metabolic needs and characteristics. Is the following statement about microbes true or false? Chemoautotrophs are microbes that can use light as a source of energy but require organic matter for carbon.

FALSE

Rob Dunn's search for microbes in belly buttons was greatly assisted by citizen scientists. With this in mind, determine whether the following statement is true or false. You have to be a trained scientist to participate in citizen science.

FALSE

Some microbes contain structures that are unique to prokaryotes. On the image below, identify which structure helps microbes swim through their environment.

Flagellum

The researchers in this chapter were searching for microbes in unusual places, such as belly buttons. Although they were unsure what they would find, they knew the organisms could be classified based on their preferred carbon source and energy source. Use the image below to label the various classifications of microbes.

Gloeocapsa (photoautotroph) Acidithiobacillus (chemoautotoph) Heliobacterium (phoheterotoph) Escherichia (chemoheterotoph)

When Rob Dunn and his group of researchers set out to characterize the microbes found in belly buttons, they were unsure what they would find. However, they understood that these microbes might possess features specific to prokaryotes. On the image below, correctly label the structures commonly found on prokaryotes.

Left-2-Right Box 1: Capsule Box 2: Pilus Box 3: Flagellum

In general, microbes can be classified based on their source of energy and their source of carbon. Identify on the image below which organism would use light as a source of energy and organic matter as a source of carbon.

Photoheterotroph (Heliobacterium)

Some microbes contain structures that are unique to prokaryotes. On the image below, identify which structure allows microbes to attach to surfaces.

Pili

When Rob Dunn and his group analyzed the microbes found in belly buttons, they rarely found microbes living in isolation. Most microbes naturally form communities in which many microbes work together and even communicate with each other. Examine the image below and determine at which stage(s) you would expect the microbes to be engaged in quorum sensing.

STAGE 5 STAGE 4 STAGE 3

Is the following statement true or false? The prokaryotes that Rob Dunn identified divide rapidly because they are simpler than eukaryotes.

TRUE

Many citizen science projects like the one to collect and analyze belly button microbes allow citizens to participate in science projects across the globe. Which of the following are examples of citizen science projects? The data collected through citizen science are just as useful as data collected in a lab.

TRUE

Some experiments requiring large numbers of participants rely on citizen scientists for data collection and analysis. Evaluate the following statement as true or false. The data collected through citizen science are just as useful as data collected in a lab.

TRUE

Some prokaryotes have an extra protective layer, called the capsule, in addition to the cell wall.

TRUE

When Rob Dunn's researchers collected specimens from the belly buttons of volunteers, they noticed that anaerobes tended to be found deep in the belly button while aerobes tended to be near the opening. What is the best explanation for this observation?

The anaerobes were deeper because that is where there is less oxygen.

While studying environmental samples collected from the ground cover of the Amazon rainforest, you isolate a new microorganism. You note that it is single-celled, lacks a nucleus, and is found only in areas of the rainforest that remain humid year-round. Based on this information, how would you best describe this organism?

The organism is a prokaryote from the domain Bacteria since it lacks organelles and lives in an ordinary environment.

We are learning that microbes are capable of surviving in environments that would be inhospitable to many other forms of life. Which of the following best describes the relationship between thermophiles and halophiles?

They are achaeans that survive in high temperatures and high salt conditions, respectively.

Bioremediation is the use of living organisms to clean up environmental disasters, such as an oil spill. If you were asked to pick the organism best suited to clean up an oil spill, which would you choose and why?

bacteria, because they would rapidly increase their population and adapt to the damaged environment

Rob Dunn's research group was able to isolate a number of organisms from their test subjects' belly buttons. Place the organisms listed below in order of reproduction rate from fastest to slowest.

bacterium, mold fungus, fish, human

Rob Dunn and Noah Fierer's search for microbes found in belly buttons has revealed that the belly button is home to many different microbes, including bacteria and even archaeans in some individuals. Complete the following statement about archaeans.

eukaryotes, prokaryotes, extreme

Biological oceanographers are investigating the ability of ocean microbes to combat climate change through the absorption of atmospheric carbon dioxide that has dissolved into surface ocean waters. Order the different metabolic strategies from the most promising to the least promising for prokaryotic carbon sequestration.

photoautotroph, chemoautotroph, photoheterotroph, chemoheterotroph

While studying the effects of a new drug on bacteria, you notice that before treatment the microbes appeared to stick together in large clumps, but after treatment they don't clump at all. What microbial structure was most likely affected by the treatment?

pili

Although bacteria and archaeans are both prokaryotes, only the archaeans are found in extreme conditions such as hot springs, where bacteria are unlikely to survive.

prokaryotes, archaeans, hot springs, bacteria

You read the following statement in a biology paper and feel that it is incorrect: "Although bacteria and archaeans are both prokaryotes, only bacteria are found in extreme conditions such as hot springs, where archaeans are unlikely to survive." How would you correct the statement?

prokaryotes, archaeans, hot springs, bacteria

What is citizen science?

science projects in which the public participates by collecting data, analyzing data, or participating as subjects.