17. What is citizen science? a) Science projects in which scientists study citizen b) Science project in which citizens are trained to become scientists in the future c) Science projects in which the public participates by collecting data, analyzing data, or participating as subjects d) Science projects in which scientists study the nature of being a good citizen
18. When considering the evolutionary tree of life and the three domains of life, which statement best describes what likely happened over the course of millions of years of evolution? Choose one:
A. Bacterial and eukaryotic cells are more closely related to each other than to archaeans, as evidenced by the fact that bacteria and eukaryotes do not inhabit the most extreme environments.
B. Although their cell structures are very different, archaean and eukaryotic cells are more closely related to each other than to bacteria, as evidenced by the fact that Bacteria was the first domain to split from the shared ancestor of Archaea and Eukarya.
C. Bacteria and archaeans are more closely related to each other than to eukaryotes, as evidenced by their cell structures. Bacteria and archaeans are prokaryotic, while all eukaryotic cells contain mitochondria and other membrane-bound organelles.
D. The three domains of life are equally divergent from one another, so no two domains are more closely related to each other. This is supported by the evolutionary tree of life because three branches extend from one node millions of years ago.
17. What is citizen science? a) Science projects in which scientists study citizen b) Science project in which citizens are trained to become scientists in the future c) Science projects in which the public participates by collecting data, analyzing data, or participating as subjects d) Science projects in which scientists study the nature of being a good citizen
18. When considering the evolutionary tree of life and the three domains of life, which statement best describes what likely happened over the course of millions of years of evolution? Choose one:
A. Bacterial and eukaryotic cells are more closely related to each other than to archaeans, as evidenced by the fact that bacteria and eukaryotes do not inhabit the most extreme environments.
B. Although their cell structures are very different, archaean and eukaryotic cells are more closely related to each other than to bacteria, as evidenced by the fact that Bacteria was the first domain to split from the shared ancestor of Archaea and Eukarya.
C. Bacteria and archaeans are more closely related to each other than to eukaryotes, as evidenced by their cell structures. Bacteria and archaeans are prokaryotic, while all eukaryotic cells contain mitochondria and other membrane-bound organelles.
D. The three domains of life are equally divergent from one another, so no two domains are more closely related to each other. This is supported by the evolutionary tree of life because three branches extend from one node millions of years ago.
Related textbook solutions
Related questions
I need help on this microbiology question:
Contrary to our favorite science fiction books and movies, the chances of us finding another planet with a civilization comparable to, or even more advanced than our own, seems highly unlikely. But, through your work as a microbiologist at NASA, you have been able to help change our views as to what forms of life we should be looking for on planets in our solar system and around neighboring stars. Instead of radio signals or errant transmissions, we have begun looking for planets that have environments similar to those capable of sustaining life as we know it here on Earth. To determine what we could find out there, you have begun studying different unique and atypical environments found here on Earth. Although the harsh conditions of hot springs or undersea sulfur vents seem incompatible with most forms of life, organisms known collectively as "extremophiles" have still managed to survive and adapt to these extreme conditions. You believe extremophiles may help you gain insight into the potential metabolic requirements, processes, and challenges of extraterrestrial life. Thus far in your search, you have identified some prokaryotic cells that have evolved to survive in the extreme conditions of sulfur vents on the sea floor. These vents are found at great depths, where the crushing pressure and lack of light and oxygen are prohibitive to many forms of life. Bacteria that are not considered extremophiles reside in most ecological niches on this planet. There are some common criteria for the environment that would sustain these bacteria. Availability of water, pH that lies between 5 and 9, temperatures that will remain steady and below boiling; these are some of the characteristics that bacteria will require in their environment if they are to succeed. But in the environment of the ocean floor vents, not only is the pH of the water very low, but also the water temperature is unusually high due to the geologic activity that fuels the vents. Organisms that are adapted to such harsh conditions have necessarily evolved enzymes able to function beyond average optima, as well as a chemosynthetic metabolism capable of using vent organic and inorganic compounds as energy sources.
Part A - Comparable Earth Environments to Be Found on Another Planet
You identify the prokaryotic cells you've found as a species of bacteria. These bacteria appear to be living off of nutrients and sulfur compounds released from the vents on the sea floor. Over time, the bacteria must have evolved extreme metabolic and enzymatic capabilities to allow them to tolerate and even benefit from the extreme depths, the lack of oxygen, the low pH of the surrounding waters, high temperatures due to volcanic releases, and the unique nutrient source of the vents.
Choose the characteristics and their impact on enzyme activity that are not correct from the following statements. (more than one may be chosen)
| Archaea are able to tolerate highly acidic pH environments and have proteins that will not denature in the low-pH environments that the bacteria are found in. |
| Archaea are able to colonize water that is at or above the boiling temperature due to high levels of disulfide bridges that maintain the three-dimensional structure of the enzyme. |
| Archaea are only able to survive exceedingly well at high temperatures due to the amount of activation energy required by their enzymes. |
| Archaea are able to grow in extremely shady or low-light conditions that allow for optimal enzyme activity. |
