Exam 27: Protists

Assume that some members of an aquatic species of motile, photosynthetic protists evolve to become parasitic to fish. They gain the ability to live in the fish gut, absorbing nutrients as the fish digests food. Over time, which of the following phenotypic changes would you expect to observe in this population of protists?

Encouraging the growth via nutrient fertilization) of photosynthetic protists in marine environments may help reduce global warming. Why?

Consider the following data: a) Most ancient eukaryotes are unicellular. b) All eukaryotes alive today have a nucleus and cytoskeleton. c) Most ancient eukaryotes lack a cell wall. Which of the following conclusions could reasonably follow the data presented?

Which of the following protists causes the human disease malaria?

Protists belong to the domain Eukarya. Which of the following is not a protist?

By examining the phylogenetic tree diagrammed above, what conclusion can you draw about the species G. microti?

Which of the following statements is consistent with the assertion that protists are paraphyletic?

How was primary productivity measured in the phytoplankton experiment?

Alternation of generations occurs in protists. Which of the following represents the correct sequence of events for this mode of reproduction?

Phytoplankton is comprised of photosynthetic protists and bacteria. For the most part, humans do not consume phytoplankton. Why, then, are they important to humans?

Which of the following observations about flagella is true and is consistent with the scientific conclusion that the flagella from protists and bacteria evolved independently?

Which of the following would be considered a carbon sink that could potentially reduce atmospheric carbon dioxide to help alleviate global warming?

A particular species of protist has obtained a chloroplast via secondary endosymbiosis. How can you tell?

What is meant by the term "high- selected" lines in the phytoplankton experiment?

How are algal blooms red tides) typically harmful to humans?

Which of the following best describes what scientists the Bell research group) concluded about the effect of atmospheric CO₂ increases on phytoplankton's primary productivity?

Use the following information when answering the corresponding questions). The mechanism of cell crawling in protist species is not well defined. The textbook states that pseudopodia extension involves interactions between actin and myosin the same molecules that are involved in mammalian muscle contraction). However, p the study described below, no one had provided convincing data that actin and myosin were actually involved in cell crawlin protists. Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in severa of protist, but physiological studies had failed to show a functional link between actin, myosin, and cell crawling. In a study by N. Poulsen et al. Diatom gliding is the result of an actin- myosin motility system, Cell Motility and the Cytoskeleto 1999):23- 22), researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin. Figure 27.3 -Latrunculin A is a reversible toxin that disrupts the formation of actin fibers. A culture of a particular species of diatom was treated with this toxin diluted in a buffer, while another culture was treated only with the buffer no toxin; control). The motility of cells in each culture was assessed by counting the number of cells that were moving during a defined period of time. Which of the following conclusion statements is reasonable based on the data in the bar graph above?

You discover a new lineage of protists. You examine several species of this lineage under the microscope and find a distinctive feature that sets them apart from other protists. Following the nomenclature style used to name the lineage Discicristata, you decide to name this new lineage Spherocristata. What is the distinctive feature that is reflected in the name?

Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in

In examining a protist, you notice that it lacks a cell wall and has movement with cytoplasmic streaming. These data allow you to infer that the species belongs to which of the following protist groups?