Chapter 28 - Book Flashcards
Chapter 28: Protists: Key Concepts
a. Most eukaryotes are single-celled organisms
b. Excavates include protists with modified mitochondria and protists with unique flagella
c. The SAR clade is a highly diverse group of protists defined by DNA similarities
d. Red algae and green algae are the closest relatives of land plants
e. Unikonts include protists that are closely related to fungi and animals
f. Protists play key roles in ecological communities
Chapter 28: Protists: Key Concepts
a. Most eukaryotes are single-celled organisms
b. Excavates include protists with modified mitochondria and protists with unique flagella
c. The SAR clade is a highly diverse group of protists defined by DNA similarities
d. Red algae and green algae are the closest relatives of land plants
e. Unikonts include protists that are closely related to fungi and animals
f. Protists play key roles in ecological communities`
a diverse, mostly unicellular group of eukaryotes
protists
T/F Most eukaryotes are:
a. single-celled organisms
b. multi-celled organisms
c. neither
a. most eukaryote are single-celled organisms
In what domain are protests classified as part of?
Eukarya
Unlike the cells of prokaryotes what do eukaryotic cells (including protists) have?
nucleus
membrane-bound organelles
You look at a prokaryotic cell under a microscope. Would you expect it to have a well-developed cytoskeleton?
No, because Eukaryotes have a well-developed cytokeleton (not prokaryotes)
Eukaryotic cells have a structural support that enables them have asymmetric forms and change in shape as they feed, move, or grow. What is this mainly due to?
Eukaryotes have a well-developed cytoskeleton
“Most organisms in eukaryotic lineages are _______ and most protists are _____.”
protists, unicellular
T/F Protists exhibit more structural and functional diversity than the eukaryotes with which we are most familiar–plants, animals, and fungi.
True
If you discover a new type of protist, is it more likely to be a unicellular or multicellular organism? Why?
Unicellular (most protists are unicellular)
Do protists (Domain Eukarya) have membrane-bound organelles and a nucleus?
Yes
You discover a protist that combines photosynthesis and heterotrophic nutrition. What is this protist classified as?
Mixotroph (combine photosynthesis and heterotrophic nutrition)
You find a unique protist which absorbs organic molecules and ingests large food particles. What is this protist classified as?
Heterotroph
What are highly varied among protists? In regards to nutrition, are protists very diverse?
reproduction and life cycles, yes
T/F all three basic types of sexual life cycles are represented among protists
True
Has kingdom Protista been abandoned? When is the term only used, now?
Yes, Protist only refers to eukaryotes that are not plants, animals or fungi (convenient)
What gave rise to the enormous diversity of protists that exist today?
Endosymbiosis
A certain organism lives inside the cells or cells of another organism. What is this an example of?
Endosymbiosis
“A defining moment in the origin of eukaryotes occurred when a host cell engulfed a bacterium that would later become an organelle found in all eukaryote–the mitochondrion.” What is this process an example of?
Endosymbiosis
Archaeplastida, Unikonta, and Excavata are three of the “supergroups” of eukaryotes on earth. Which supergroup is missing?
“SAR Clade”
You find a eukaryotic species with an hollowed out groove on one side of the cell body. What supergroup in Domain Eukarya does this species belong to?
Excavata
There are three major branches of living organisms (excluding viruses). Name them.
Eukarya, Archaea, Bacteria
You find a parasite that looks almost exactly like the parasite Giardia. What sub-category and supergroup of Domain Eukarya might it belong to?
Diplomonad, Excavata
List the three subgroups of the supergroup Excavata in the domain Eukarya
Diplomonads
Parabasalids
Euglenozoans
This parasite inhabits the intestines of mammals. It can infect people when they drink water contaminated with feces containing this parasites’ cysts. Drinking such can cause severe diarrhea. Boiling the water kills the parasite. What is this parasite and its categorization?
Giardia intestinalis, diplomonad parasite, supergroup Excavata, domain Eukarya
List the nine subcategories of “SAR” Clade - Eukarya
Diatoms Golden Algae Brown Algae Dinoflagellates Apicomplexans Ciliats Forams Cercozoans Radiolarians
Name the three large and diverse clades of “SAR” clade
stramenopiles
alveolata
rhizaria
Diatoms are part of what sub-category of what supergroup in the domain Eukarya?
Stramenopiles, “SAR” Clade
These beautiful single-celled protists are important photosynthetic organisms in aquatic communities
Diatoms
You find an amoeba with a pseudopodia that is threadlike in shape. The pseudopodia is an extension that bulges from the cell to capture prey. How is this amoeba classified?
amoebas are in the rhizarian subgroup of the SAR Clade
This supergroup of eukaryotes includes red and green algae, along with land plants.
Archaeplastida
Along Bodega Bay, there is quite a bit of seaweed. What is this large algae most likely named?
multicellular red or green algae in the supergroup Archaeplastida of the domain Eukarya
You find a colonial freshwater green alga. What supergroup of Eukarya is this a part of?
Archaeplastida (chlorophyte or charophyte)
Why are Archaeplastida protists important?
They include key photosynthetic species that form the base of the food web in some aquatic communities
You find an amoeba X that has a lobe-shaped (or maybe tube-shaped, you can’t tell!) pseudopodia. You also find an amoeba Y which has a threadlike pseudopodia which it uses to move. According to pg. 591:
a. Amoeba X is part of the supergroup ______
b. Amoeba Y is part of the supergroup _______
a. Unikonta (amoebas have lobe- or tube-shaped pseudopodia)
b. SAR Clade (amoebas have threadlike pseudopodia)
Figure 28.3
Studies of eukaryotes show that a cyanobacterium was engulfed by an ancestral heterotrophic eukaryote (primary endosymbiosis). That ancestor then diversified into red algae and green algae, some of which was subsequently engulfed by other eukaryotes (secondary endosymbiosis). What did this process likely produce?
the diversity of plastids that we see in eukaryotes
What event gave rise to eukaryotes?
The descent of mitochondria from a bacterium that was engulfed by a cell from an archaea lineage = endosymbiosis.
According to Figure 28.3, the plastid bearing lineage gave rise to what two lineages of photosynthetic protists, or ____?
algae, red algae and green algae
Concept 28.2
“Excavates include protists with modified mitochondria and protists with unique flagella”
Concept 28.2
“Excavates include protists with modified mitochondria and protists with unique flagella”
If a biologist discovers a protist with a modified mitochondria or a unique flagella, what supergroup of eukaryotes is this protist a part of?
Excavata (Domain Eukarya)
T/F Most diplomonads and parabasalids (Excavata - Eukarya) are found in aerobic environments.
False. They are mostly found in anaerobic environments.
T/F Most diplomonads and parabasalids (Excavata - Eukarya) are found in aerobic environments.
False. They are mostly found in anaerobic environments.
The only eukaryotes to lack “mitochondria”
Diplomonads and Parabasalids - Excavata - Eukarya
You find a eukaryote that has mitosomes, is anaerobic and has a simple cytoskeleton with two nuclei. What classification would you give this organism?
Diplomonad - Excavata - Eukarya
Trichomonas vaginalis is an example of a ____ or ____ in the supergroup ________
trichomonads, parabasalids, Excavata
Giardia lamblia is in what subcategory of Excavata?
Diplomonads
You find an organism that is flagellated with paramylum used as storage and is autotrophic. What classification should this organism be given?
Euglenoid - Euglenozoa - Excavata
African Sleeping Sickness and Chagas’ disease are derived from Typanosoma bruci and Trypanosoma cruzi, respectively. What classification should these parasites be given?
These two disease are from two Kinetoplastids, in the Euglenozoa, in the supergroup Excavata in the domain Eukarya
Kinetoplastids - Euglenozoans - Excavata
T. brucei is shaped like a ________
T. cruzi is shaped like a _____
b. , spirally shape
c. crescent
SAR Clade - Alveolate
a.
b.
c.
Dinoflagellates
Apicomplexans
Ciliates
What clade is believed to have evolved from a common ancestor derived by secondary endosymbiosis of a red algae?
SAR Clade
You learn of a subcategory of the SAR Clade that has the following characteristics. What is the name of this subcategory?
a. organisms possess small membrane-bound activities called alveoli under their cell surfaces
b. come in three groups, including photosynthetic and parasitic organisms.
Alveolates
You find a species that produces large blooms in marine environments that cause red and brown tides. The tides poison the fish and the collected shell fish cause food poisoning. How would you classify this organism?
Dinoflagellate - Alveolate - SAR Clade - Domain Eukarya
probably unicellular
You discover an organism which is a known neurotoxin and causes paralytic shell fish poisoning when contaminated shellfish have been eaten. What classification would you give this organism?
Dinoflagellate - Alveolate - SAR Clade
You discover an organism which is a known neurotoxin and causes paralytic shell fish poisoning when contaminated shellfish have been eaten. What classification would you give this organism?
Dinoflagellate - Alveolate - SAR Clade
This subcategory of Alveolate - SAR Clade - Eukarya has the following characteristics. What is its name?
a. Parasites on an animal host
b. Parasites spread through host as sporozoites
c. Parasites have modified plastids called apicoplasts
Apicomplexans
The Mosquito - Malaria - Life Cycle
a. The infected mosquito bites another person, infecting the person with the Plasmodium _____
b. The ____ enter the victim’s liver cells. After several days they undergo multiple divisions to become ___ which then use their apical complexes to penetrate the victim’s _____ ______ cells.
c. The merozoites grow and divide __ until numbers of new merozoites repeatedly break out of the blood cells at intervals of 48-72 hours. This causes periodic chills and ____.
d. Some _____ divide to form ____ which complete the life cycle of a new female mosquito.
_________________________
a. ____ Anopheles mosquito bites a person infected with malaria and picks up Plasmodium gametocytes along with blood
b. Gametes form from male and female gametocytes; fertilization occurs in the mosquito’s _ ____, and a zygote forms (the zygote is the only -__ stage in the life cycle).
c. An oocyst develops from the zygote in the wall of the mosquito’s gut.
a. sporozoites
b. sporozoites, merozoites, liver
c. asexually, fever
d. merozoites, gametocytes
a. Female
b. digestive tract
c. diploid
Nearly all apicomplexans (Alveolate - SAR Clade - Eukarya) are _________ of animals
parasites
a large and varied group of protists named for their use of cilia to move and feed (in the Alveolate sub-group of protists)
ciliates
What is a distinctive morphological feature of ciliates (Alveolates)?
ciliates (Alveolates - SAR Clade - Protists) have two types of nuclei: tiny micronuclei and large macronuclei - a cell has one or more nuclei of each type
Many species in this group are amoebas, protists that move and feed by means of pseudopodia–extensions that may bulge from almost anywhere on the cell surface.
Rhizarians (subgroup of the SAR Clade - Protists))
Name three groups of rhizarians
radiolarians, Forams, cercozoans
The protists called ______ have delicate, intricately symmetrical internal skeletons made of silica.
Radiolarians (Rhizarians - SAR Clade -Protists)
Protists that are named for their porous shells, or tests–a single piece of organic material hardened with calcium carbonate.. Found in both the ocean and fresh water. Mostly fossils.
Forams (Rhizarians - SAR Clade - Protists)
A large group of amoeboid and flagellated protists that feed using threadlike pseudopodia. Common inhabitants of marine, freshwater and soil ecosystems.
Cercozoans (Rhizarians - SAR Clade - Protists)
The closest relatives of land plants
Red algae and green algae (Archaeplastida - Eukaryotic supergroup)
red algae, green algae, and land plants
archaeplastida
a supergroup of eukaryotes that evolved from an ancient protist which engulfed a cyanobacterium
archaeplastida
the most abundant large algae int he warm coastal waters of tropical oceans
red algae
The grass green chloroplasts of _______ have a structure and pigment composition much like the chloroplasts of land plants
green algae
The two divisions of green algae (Archaeplastida - Eukaryotes)
Chlorophytes
Charophytes
This Eukaryotic supergroup includes protists that are closely related to fungi and animals
Unikonts
An extremely diverse supergroup of eukaryotes that includes animals, fungi, and some protists
Unikonts
Amoebozoans and opisthokonts
the two major clades of the unikont supergroup
This clade includes many species of amoebas that have lobe- or tube-shaped pseudopodia, rather than the threadlike pseudopodia found in rhizarians.
Amoebozoan clade (Unikonts - Eukaryote)
T/F Protists play key roles in ecological communities
True
Most protists are _____ and they are found almost anywhere there is water, including moist terrestrial habitats such as damp soil and leaf litter. The two key roles that protists play in their environment: ___ and _____
aquatic, symbiont, producer
Some protists inhabit the gut of many termite species. Unaided, termites cannot digest wood and they rely on protistan or prokaryotic symbionts to do so. What is this an example of?
Symbiotic protists
Photosynthetic dinoflagellates (Aleveolates _ SAR Clade _ Eukaryotes) are food providing partners of the animals that build coral reefs. This is an example of:
Symbiotic protists
P. infestans caused potato late blight, which turned the stalks and stems of potato plants into black slime. It contributed to the devastating Irish famine of the 19th. cent. What type of protist caused this blight?
Symbiotic parasitic protist. “Symbiotic protists also include parasites that have compromised the economies of entire countries.”
Many protists are important ____, organisms that use energy from light to convert carbon dioxide to organic compounds
producers
What type of protist forms the base of ecological food webs?
Producer protists
In aquatic communities, the main producers are ____ and ____-
photosynthetic protists and prokaryotes
When fertilizer is applied to a field, some of the fertilizer may be washed by rainfall into a river that drains into a lake. What phenomena may then occur?
The abundance of photosynthetic protists in that region may increase spectacularly (increase in nutrients to aquatic communities)
What three nutritional modes/types may protists be typified by?
Protists include photoautotrophs, heterotrophs, and mixotrophs
An archaea host engulfed an alpha proteo-bacterium that would evolve into the mitochondrion. What may have originated by this process of endosymbiosis?
Eukaryotes
In one hypothesis, eukaryotes are grouped into four supergroups, each a monophyletic clade: - - - -
Excavata (Diplomonads, parabasalids, euglenozons)
SAR Clade (stramenopiles, Alveolates, rhizarians)
Archaeplastida (red algae, green algae, land plants)
Unikonts (amoebozoans, opisthokonts)
Giardia Trichomonas and Typanosoma, Euglena belong in what supergroup?
Excavata
Paramecium and amoebas with thread-like pseudopodia belong in what group?
SAR Clade
mosses, ferns, conifers and flowering plants and algae belong in what Eukaryotic supergroup?
Archaeplastida
Amoebas with lobe-shaped or tube-shaped pseudopodia and animals and fungi belong in what group?
Unikonts
_______ include protists with modified mitochondria and protists with unique flagella.
_____ is a highly diverse group of protists defined by DNA similarities (hairy and smooth flagella, alveoli, amoebas)
________ include red and green algae and land plants with plant-type chloroplasts
______ include protists the are closely related to fungi and animals, including slime molds, Amoebozoans with lobe-shaped or tube-shaped pseudopodia
Excavata
SAR Clade
Archaeplastida
Unikonts
CC. 28 - Level 1 Plastids that are surrounded by more than two membranes are evidence of: a. evolution from mitochondria b. fusion of plastids c. origin of the plastids from archaea d. secondary endosymbiosis
d. secondary endosymbiosis
CC 28 - Level 1
Biologists think the endosymbiosis gave rise to mitochondria before plastids because:
a. the products of photosynthesis could not be metabolized without mitochondrial enzymes
b. all eukaryotes have mitochondria (or their remnants) whereas many eukaryotes do not have plastids
c. mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA
d. without mitochondrial CO2 production, photosynthesis could not occur
b. all eukaryotes have mitochondria (or their remnants) whereas many eukaryotes do not have plastids
CC 28 Level 1
Which group is incorrectly paired with its description?
a. diatoms - important producers in aquatic communities
b. red algae - eukaryotes that acquired plastids by secondary endosymbiosis
c. apicomplexans - unicellular parasites with intricate life cycles
d. diplomonads - unicellular eukaryotes with modified mitochondria
b. red algae - eukaryotes that acquired plastids by secondary endosymbiosis
CC 28 Level 1 According to the phylogeny presented in this chapter, which protists are int he same eukaryotic supergroup as land plants? a. green algae b. dinoflagellates c. red algae d. both a and c
d. red algae and green algae are in the same supergroup as land plants (Archaeplastida)
CC 28 Level 1 In a lifecycle with alternation of generations, multicellular haploid forms alternate with: a. unicellular haploid forms b. unicellular diploid forms c. multicellular haploid forms d. multicellular diploid forms
multicellular diploid forms
Based on the phylogenetic tree in Figure 28.2, which of the following statements is correct?
a. The most recent common ancestor of Excavata is older than that of the SAR clade
b. the most recent common ancestor of the SAR clade is older than that of the Unikonta
c. The most basal (first to diverge) eukaryotic supergroup cannot be determined
d. Excavata is the most basal eukaryotic supergroup
c. the most basal (first to diverge) eukaryotic supergroup cannot be determined
28: Concept Check
List at least four examples of structural and functional diversity among protists
Protists include unicellular, colonial and multicellular organisms; photoautotrophs, heterotrophs, and mixotrophs; species the reproduce asexually, sexually or both ways, organisms with diverse physical forms and adaptations
28: Concept Check 1
Summarize the role of endosymbiosis in eukaryotic evolution
Strong evidence shows that eukaryotes acquired mitochondria after a host cell first engulfed and then formed an endosymbiotic association with an alphaproteobacterium.
Similarly, chloroplasts in red and green algae appear to have descended from a photosynthetic cyanobacterium that was engulfed by an ancient heterotrophic eukaryote.
Secondary endosymbiosis also played an important role. Various lineages acquired plastids by engulfing unicellular red or green algae.
28: Concept Check 2
Why do some biologists describe the mitochondria of diplomonads and parabasalids as “highly reduced”?
Their mitochondria do not have an electron transport chain and so cannot function in aerobic respiration.
28: Concept Check 28.3
Explain why format have such a well-preserved fossil record
Because Foram tests are hardened with calcium carbonate, they form long lasting fossils in marine sediments and sedimentary rocks.
28: Concept Chic 28.3
Would you expect the plastid DNA of photosynthetic dinoflagellates, diatoms and golden algae to be more similar to the nuclear DNA of plants or to the chromosomal DNA of cyanobacteria?
The plastid DNA would be more similar to the chromosomal DNA of cyanobacteria based on the hypothesis that eukaryotic plastids originated by an endosymbiosis event in which a eukaryote engulfed a cyanobacterium. If the plastid is derived from the cyanobacterium, its DNA would be derived from the bacterial DNA.
28: Concept Check 28.4
Compare and contrast red algae and brown algae
Many red algae contain a photosynthetic pigment called phycoerythrin, which gives them a reddish color and allows them to carry out photosynthesis in relatively deep coastal water. Also, unlike brown algae, red algae have no flagellated stages in their life cycle and must depend on water currents to bring gametes together for fertilization.
28: Concept Check 28.5
a. Contrast the pseudopodia of amoebozoans and forams.
Amoebozoans have lobe or tube-shaped pseudopodia while forams have threadlike pseudopodia.
28: Concept Check 28.5
In what sense is “fungous animal” a fitting description of a slime mold? In what sense is it not?
Slime molds are fungus-like in that they produce fruiting bodies that aid in the dispersal of spores, and they are animal-like in that they are motile and ingest food. However, slime molds are more closely related to tubulinids and entamoeba than to fungi or animals
28: Concept Check 28.6
Justify the claim that photosynthetic protists are among the biosphere’s most important organisms
Because photosynthetic protists constitute the basis of aquatic food webs, many organisms depend not hem for food (either directly or indirectly). Ina addition, a substantial percentage of the oxygen produced by photosynthesis is made by photosynthetic protists.
28: Concept Check 28.6
Describe three symbioses that include plants
Protists form mutualistic and parasitic relationships with organisms.
Examples: photosynthetic dinoflagellates form a mutualistic symbiosis with coral polyps, parabasalids form a mutualistic symbiosis with termites
28: Concept Check 28.6
High water temps. and pollution can cause corals to expel their dinoflagellate symbionts. How might such “coral bleaching” affect corals and other species?”
Coral depend on their dinoflagellate symbionts for nourishment, so coral bleaching would cause the corals to die. As a result, less food would be available for fishes and other species -> populations of these species would decline -> populations of their species may decline
