Why have protists been "mixed in" with plants, animals, and fungi under the hypothesis that groups eukaryotes into five supergroups?
-Many protists are more closely related to plants, animals, or fungi than they are to each other.
-Recent evidence makes it clear that the former kingdom Protista was paraphyletic.
(Both the first and third answers are correct)
The placement of all protists in one kingdom caused dissatisfaction among taxonomists mainly because _____.
various pieces of evidence indicate that the kingdom Protista cannot be monophyletic
Which of the following is one of the main weaknesses of the proposed classification scheme in which all eukaryotes are divided into five supergroups?
It shows all five supergroups diverging simultaneously from a common ancestor.
Organisms are classified as Excavata based on _____.
morphological studies of the cytoskeleton
Which example below is a characteristic shared by diplomonads and parabasalids?
Both lack plastids.
How do trypanosomes withstand the attack of a host's immune system?
The molecular composition of their surface changes continually.
Which of these groups includes photosynthetic unicellular organisms with flagella and contractile vacuoles?
euglenids
Although controversial, chromalveolates are proposed as a clade whose common ancestor _____.
engulfed a photosynthetic red algae in a secondary endosymbiosis event
Apicomplexans are currently assigned to the chromalveolates because _____.
the apicoplast, a modified plastid, appears to be of red algal origin
In many types of protist life cycles, the union of two gametes that results in a diploid zygote is called _____.
syngamy
What do a carnivorous dinoflagellate, a parasitic apicomplexan, and a ciliate have in common?
All three have sacs known as alveoli just beneath their plasma membranes.
Which organisms are capable of producing a "red tide"?
dinoflagellates
Which of these groups includes species that produce a substance that is toxic to humans?
dinoflagellates
Which of these groups includes parasitic unicellular organisms with a complex of organelles specialized for penetrating host cells and tissues?
apicomplexans
Which of these groups is characterized by cells that have more than one nucleus?
ciliates
How do ciliates generate genetic variation?
conjugation
Which protists were once categorized as fungi due to their multinucleate filaments that resemble hyphae?
oomycetes
_____ is a protist that causes late blight of potatoes and was responsible for the Irish potato famine of the 19th century.
Phytophthora infestans
Which of these groups includes unicellular organisms that, due to the structure of their cell walls, can withstand pressures equal to the pressure under each leg of a table supporting an elephant?
diatoms
Which characteristic is shared by most diatoms, golden algae, and brown algae at least at some stage of their life cycles?
-All are autotrophs.
-They all have flagella with numerous fine, hairlike projections.
-All are stramenopiles.
-All of the listed responses are correct.
(all of them are correct)
The general term given to a plantlike body that lacks true stems, leaves, and roots and that shows little tissue differentiation is _____.
thallus
What is the purpose of the "floats" in some brown algae?
facilitating photosynthesis
Which of the following organisms is commercially harvested to extract algin from their cell walls?
brown algae
What role do diatoms play in the global carbon balance affecting global warming?
During a bloom, diatom populations may increase rapidly. If many diatoms die and sink to the bottom without being eaten, they effectively pump carbon dioxide out of the atmosphere.
On some areas of the seafloor, one could observe an "ooze" that is hundreds of meters thick. What creates this ooze?
the tests of dead radiolarians
Many species of red algae are adapted to deeper water due to the fact that _____.
their photosynthetic pigments efficiently absorb blue and green light
The red algae are characterized by _____.
especially diverse life cycles
Which of the following groups of algae is/are most closely related to land plants?
green algae
In lab class, a plasmodial slime mold is used as a demonstration organism. One of the students does not understand why this organism is not considered multicellular. How would you explain it to her?
The plasmodium is undivided by membranes and contains many diploid nuclei; therefore, it is not technically multicellular.
To which supergroup do amoebas belong?
None of the listed responses is correct.
It is estimated that protists perform up to what percentage of the world's photosynthesis?
30%
Hypermastigotes are important endosymbionts that live in the guts of _____.
termites