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75 Cards in this Set

  • Front
  • Back
Protists are...



Eukaryotic cells have...




It is important to bear in mind that...

Protists are eukaryotes



Eukaryotic cells have organelles and are more complex than prokaryotic cells




It is important to bear in mind that


1. The organisms in most eukaryotic lineages are protists


2. Most protists are unicellular

Protists exhibit more structural and functional diversity than...



Though most protists are unicellular, there are...




Single-celled protists can be very complex, as all biological functions are carried out by...

Protists exhibit more structural and functional diversity than any other group of eukaryotes



Though most protists are unicellular, there are some colonial and multicellular species




Single-celled protists can be very complex, as all biological functions are carried out by organelles in each individual cell

Protists, the most nutritionally diverse of all eukaryotes, include...
Protists, the most nutritionally diverse of all eukaryotes, include:

1. Photoautotrophs, which contain chloroplasts




2. Heterotrophs, which absorb organic molecules or ingest larger food particles




3. Mixotrophs, which combine photosynthesis and heterotrophic nutrition

Some protists reproduce asexually, while...
Some protists reproduce asexually, while others reproduce sexually, or by the sexual processes of meiosis and fertilization
Four Supergroups of Eukaryotes

It is no longer thought that amitochondriates (lacking mitochondria) are the oldest lineage of eukaryotes




Many protists have been shown to have...




One hypothesis divides all eukaryotes (including protists) into...

Four Supergroups of Eukaryotes

It is no longer thought that amitochondriates (lacking mitochondria) are the oldest lineage of eukaryotes




Many protists have been shown to have mitochondria and have been reclassified




Our understanding of the relationships among protist groups continues to change rapidly




One hypothesis divides all eukaryotes (including protists) into four supergroups

There is now considerable evidence that much protist diversity has its origins...



Endosymbiosis is a relationship between...

There is now considerable evidence that much protist diversity has its origins in endosymbiosis



Endosymbiosis is a relationship between two species in which one organism lives inside the cell or cells of the other organism (the host)

Mitochondria and plastids are derived from prokaryotes that...



Mitochondria evolved once by...




Plastids evolved later by...




The ancestral host cell may have been...

Mitochondria and plastids are derived from prokaryotes that were engulfed by the ancestors of early eukaryotic cells



Mitochondria evolved once by endosymbiosis of an alpha proteobacterium




Plastids evolved later by endosymbiosis of a photosynthetic cyanobacterium




The ancestral host cell may have been an archaean or a “protoeukaryote,” from a lineage related to, but diverged from archaeal ancestors

Mitochondria arose first through descent from a bacterium that was...



The plastid lineage evolved later from...




The plastid-bearing lineage of protists evolved into...

Mitochondria arose first through descent from a bacterium that was engulfed by a cell from an archaeal lineage



The plastid lineage evolved later from a photosynthetic cyanobacterium that was engulfed by a heterotrophic eukaryote




The plastid-bearing lineage of protists evolved into photosynthetic protists, red and green algae

Illustrate the arrival of plastids, beginning with the most recent common ancestor.

Like cyanobacteria, plastids of red algae and green algae have...




Transport proteins in the membranes of red and green algae are homologous to...

Like cyanobacteria, plastids of red algae and green algae have two membranes



Transport proteins in the membranes of red and green algae are homologous to those found in cyanobacteria

On several occasions during eukaryotic evolution, red and green algae underwent ...



For example, chlorarachniophytes likely evolved when...

On several occasions during eukaryotic evolution, red and green algae underwent secondary endosymbiosis, in which they were ingested by a heterotrophic eukaryote



For example, chlorarachniophytes likely evolved when a heterotrophic eukaryote engulfed a green alga




The engulfed cell contains a vestigial nucleus called a nucleomorph

Illustrate the basic morphology of the Chlorarachniophyte.
Concept 28.2: Excavates include protists with modified...



The clade Excavata is characterized by...




Some members have an “excavated”...




This group includes the...





Concept 28.2: Excavates include protists with modified mitochondria and protists with unique flagella


The clade Excavata is characterized by its cytoskeleton


Some members have an “excavated” feeding groove


This group includes the diplomonads, parabasalids, and euglenozoans

Diplomonads and Parabasalids

These two groups lack... and most live in...




Diplomonads


-Have reduced mitochondria called...


-Derive energy from ...


-Have two equal-sized ... and multiple ...


-Are often...

Diplomonads and Parabasalids


-These two groups lack plastids, have modified mitochondria, and most live in anaerobic environments




Diplomonads


-Have reduced mitochondria called mitosomes




-Derive energy from anaerobic biochemical pathways




-Have two equal-sized nuclei and multiple flagella


Are often parasites, for example, Giardia intestinalis

Parabasalids

Have reduced mitochondria called ... that generate some ...




Include ...

Parabasalids


Have reduced mitochondria called hydrogenosomes that generate some energy anaerobically




Include Trichomonas vaginalis, the pathogen that causes yeast infections in human females

Euglenozoans

Euglenozoa is a diverse clade that includes predatory...




The main feature distinguishing them as a clade is...




This clade includes...

Euglenozoans


Euglenozoa is a diverse clade that includes predatory heterotrophs, photosynthetic autotrophs, mixotrophs, and parasites




The main feature distinguishing them as a clade is a spiral or crystalline rod inside their flagella




This clade includes the kinetoplastids and euglenids

Kinetoplastids

Kinetoplastids have a single...




Free-living species are consumers of...

Kinetoplastids


Kinetoplastids have a single mitochondrion with an organized mass of DNA called a kinetoplast




Free-living species are consumers of prokaryotes in freshwater, marine, and moist terrestrial ecosystems




Some species are parasitic




Kinetoplastids in the genus Trypanosoma cause sleeping sickness in humans




Another pathogenic trypanosome causes Chagas’ disease

Kinetoplastids (cont'd)

Trypanosomes evade immune responses by...



A cell produces millions of...




These frequent changes prevent...

Trypanosomes evade immune responses by switching surface proteins


A cell produces millions of copies of a single protein


The new generation produces millions of copies of a different protein


These frequent changes prevent the host from developing immunity

Euglenids

Euglenids have one or two...


Some species can be...

Euglenids


Euglenids have one or two flagella that emerge from a pocket at one end of the cell


Some species can be both autotrophic and heterotrophic

Illustrate the morphology of Euglenids.
Describe the naming of the SAR clade.



This group is one of the most...

Concept 28.3: The “SAR” clade is a highly diverse group of protists defined by DNA similarities


The “SAR” clade is a diverse monophyletic supergroup named for the first letters of its three major clades stramenopiles, alveolates, and rhizarians




This group is one of the most controversial of the four supergroups

Illustrate the phylogeny of the SAR clade.
Stramenopiles

The stramenopiles clade includes some of the most important ...




Most have a...




Stramenopiles include...

Stramenopiles


The stramenopiles clade includes some of the most important photosynthetic organisms on Earth


Most have a “hairy” flagellum paired with a “smooth” flagellum


Stramenopiles include diatoms, golden algae, and brown algae

Diatoms

Diatoms are unicellular...

Diatoms


Diatoms are unicellular algae with a unique two-part, glass-like wall of silicon dioxide

Golden Algae

Golden algae are named for their...




The cells of golden algae are typically ...




All golden algae are...




Most are...

Golden Algae


Golden algae are named for their color, which results from their yellow and brown carotenoids


The cells of golden algae are typically biflagellated, with both flagella near one end


All golden algae are photosynthetic, and some are mixotrophs


Most are unicellular, but some are colonial

Brown Algae

Brown algae are the largest and most...


All are...


Brown algae include many...

Brown Algae


Brown algae are the largest and most complex algae


All are multicellular, and most are marine


Brown algae include many species commonly called “seaweeds”

Giant seaweeds called kelps...



Brown algal seaweeds have plantlike...




Similarities between algae and plants are examples of...

Giant seaweeds called kelps live in deep parts of the ocean




Brown algal seaweeds have plantlike structures: the rootlike holdfast, which anchors the alga, and a stemlike stipe, which supports the leaflike blades




Similarities between algae and plants are examples of analogous structures

Illustrate the 3 main structural features of the Brown algal seaweeds.
Alternation of Generations

A variety of life cycles have evolved among...




The most complex life cycles include an...




Heteromorphic generations are structurally...

Alternation of Generations


A variety of life cycles have evolved among the multicellular algae


The most complex life cycles include an alternation of generations, the alternation of multicellular haploid and diploid forms


Heteromorphic generations are structurally different, while isomorphic generations look similar

The diploid sporophyte produces haploid flagellated...



The zoospores develop into...




Fertilization of gametes results in...

The diploid sporophyte produces haploid flagellated spores called zoospores




The zoospores develop into haploid male and female gametophytes, which produce gametes




Fertilization of gametes results in a diploid zygote, which grows into a new sporophyte

Illustrate the life cycle of zoospores, including meiosis and fertilization.
Alveolates

Members of the clade Alveolata have membrane-enclosed...




The alveolates include...

Alveolates


Members of the clade Alveolata have membrane-enclosed sacs (alveoli) just under the plasma membrane


The alveolates include:


1. Dinoflagellates


2. Apicomplexans


3. Ciliates

Dinoflagellates

Dinoflagellates have two flagella...




They are abundant...




They are a diverse...




Toxic "red tides" are caused by...

Dinoflagellates


Dinoflagellates have two flagella and each cell is reinforced by cellulose plates


They are abundant components of both marine and freshwater phytoplankton


They are a diverse group of aquatic phototrophs, mixotrophs, and heterotrophs


Toxic “red tides” are caused by dinoflagellate blooms

What causes Red tide in the Gulf of Carpentaria in Northern Australia.
Apicomplexans

Apicomplexans are parasites of animals, and some cause serious...




They spread through...




One end, the apex, contains...




Most sexual and asexual...

Apicomplexans


Apicomplexans are parasites of animals, and some cause serious human diseases


They spread through their host as infectious cells called sporozoites


One end, the apex, contains a complex of organelles specialized for penetrating host cells and tissues


Most have sexual and asexual stages that require two or more different host species for completion

The apicomplexan Plasmodium is the parasite that causes...



Plasmodium requires both mosquitoes and...




Approximately 900,000 people...




Efforts are ongoing to...

The apicomplexan Plasmodium is the parasite that causes malaria


Plasmodium requires both mosquitoes and humans to complete its life cycle


Approximately 900,000 people die each year from malaria


Efforts are ongoing to develop vaccines that target this pathogen

Illustrate the life cycle of Plasmodium.
Ciliates

Ciliates, a large varied group of protists, are named for their...




They have large...




Genetic variation results from...




Conjugation is a...

Ciliates


Ciliates, a large varied group of protists, are named for their use of cilia to move and feed


They have large macronuclei and small micronuclei




Genetic variation results from conjugation, in which two individuals exchange haploid micronuclei




Conjugation is a sexual process, and is separate from reproduction, which generally occurs by binary fission

Rhizarians

Many species in the rhizarian clade are ...




Amoebas are protists that...




Rhizarian amoebas differ from amoebas in other clades by...




Rhizarians include...

Rhizarians


Many species in the rhizarian clade are amoebas


Amoebas are protists that move and feed by pseudopodia, extensions of the cell surface


Rhizarian amoebas differ from amoebas in other clades by having threadlike pseudopodia


Rhizarians include radiolarians, forams, and cercozoans

Radiolarians

Marine protists called radiolarians have delicate...




Radiolarians use their pseudopodia to...




The pseudopodia of radiolarians...

Radiolarians


Marine protists called radiolarians have delicate, symmetrical internal skeletons that are usually made of silica


Radiolarians use their pseudopodia to engulf microorganisms through phagocytosis


The pseudopodia of radiolarians radiate from the central body

Forams

Foraminiferans, or forams, are named for porous...


Pseudopodia extend through...


Many forams have...


Foram tests in marine sediments form...

Forams


Foraminiferans, or forams, are named for porous, generally multichambered shells, called tests


Pseudopodia extend through the pores in the test


Many forams have endosymbiotic algae




Foram tests in marine sediments form an extensive fossil record


Researchers can use measures of the magnesium content in fossilized forams to estimate changes in ocean temperature over time

Cercozoans

Cercozoans include most amoeboid and...


They are common in...


Most are...

Cercozoans


Cercozoans include most amoeboid and flagellated protists with threadlike pseudopodia


They are common in marine, freshwater, and soil ecosystems


Most are heterotrophs, including parasites and predators

Paulinella chromatophora is an autotroph with...



This structure evolved from a different cyanobacterium than...

Paulinella chromatophora is an autotroph with a unique photosynthetic structure called a chromoatophore




This structure evolved from a different cyanobacterium than the plastids of other photosynthetic eukaryotes

Concept 28.4: Red algae and green algae are the closest relatives of land plants

Plastids arose when a heterotrophic protist acquired a...




The photosynthetic descendants of this ancient protist evolved into...




Land plants are descended from...




Archaeplastida is the supergroup that includes...





Concept 28.4: Red algae and green algae are the closest relatives of land plants


Plastids arose when a heterotrophic protist acquired a cyanobacterial endosymbiont




The photosynthetic descendants of this ancient protist evolved into red algae and green algae




Land plants are descended from the green algae




Archaeplastida is the supergroup that includes red algae, green algae, and land plants

Illustrate the divergences of red algae, green algae, and land plants.
Red AlgaeRed algae are reddish in color due to an accessory pigment called...



The color varies from greenish-red in...




Red algae are usually multicellular; the largest are...




Red algae are the most...



Red Algae


Red algae are reddish in color due to an accessory pigment called phycoerythrin, which masks the green of chlorophyll


The color varies from greenish-red in shallow water to dark red or almost black in deep water


Red algae are usually multicellular; the largest are seaweeds


Red algae are the most abundant large algae in coastal waters of the tropics

Give three examples of red algae.
Green Algae

Green algae are named for...




Plants are descended from...




The two main groups are the...




Charophytes are most closely related to...

Green Algae


Green algae are named for their grass-green chloroplasts


Plants are descended from the green algae


Green algae are a paraphyletic group


The two main groups are the charophytes and the chlorophytes


Charophytes are most closely related to land plants

Larger size and greater complexity evolved in chlorophytes by:

The formation of colonies...


The formation of true multicellular...


The repeated division...

Larger size and greater complexity evolved in chlorophytes by:


The formation of colonies from individual cells


The formation of true multicellular bodies by cell division and differentiation (e.g., Ulva)


The repeated division of nuclei with no cytoplasmic division (e.g., Caulerpa)

Give two examples of Green Algae
Most chlorophytes have complex life cycles...
Most chlorophytes have complex life cycles with both sexual and asexual reproductive stages
Illustrate the complex life cycle of the Chlorophyte, with both sexual and asexual reproductive stages.
Concept 28.5: Unikonts include protists that are closely related...

The supergroup Unikonta includes...


This group includes two clades: the...


The root of the eukaryotic tree remains...


It is unclear whether unikonts separated from other eukaryotes...

Concept 28.5: Unikonts include protists that are closely related to fungi and animals


The supergroup Unikonta includes animals, fungi, and some protists


This group includes two clades: the amoebozoans and the opisthokonts (animals, fungi, and related protists)


The root of the eukaryotic tree remains controversial


It is unclear whether unikonts separated from other eukaryotes relatively early or late

Illustrate the questionable phylogeny of Unikonta.
Amoebozoans

Amoebozoans are amoeba that have...




They include...

Amoebozoans


Amoebozoans are amoeba that have lobe- or tube-shaped, rather than threadlike, pseudopodia




They include slime molds, tubulinids, and entamoebas

Slime Molds

Slime molds, or mycetozoans, were once...




DNA sequence analyses indicate that the resemblance between slime molds...




Slime molds include two lineages...

Slime Molds


Slime molds, or mycetozoans, were once thought to be fungi




DNA sequence analyses indicate that the resemblance between slime molds and fungi is a result of convergent evolution




Slime molds include two lineages, plasmodial slime molds and cellular slime molds

Plasmodial Slime Molds

Many species of plasmodial slime molds are brightly...

Plasmodial Slime Molds


Many species of plasmodial slime molds are brightly pigmented, usually yellow or orange

Illustrate the life cycle of Plasmodial slime molds.
At one point in the life cycle, plasmodial slime molds form a mass...



The plasmodium is not...




It is undivided by plasma membranes and contains...




It extends pseudopodia through...

At one point in the life cycle, plasmodial slime molds form a mass called a plasmodium (not to be confused with malarial Plasmodium)




The plasmodium is not multicellular




It is undivided by plasma membranes and contains many diploid nuclei




It extends pseudopodia through decomposing material, engulfing food by phagocytosis

Cellular Slime Molds

Cellular slime molds form multicellular...




Cells feed individually but can aggregate...


Dictyostelium discoideum is an experimental model...

Cellular Slime Molds


Cellular slime molds form multicellular aggregates in which cells are separated by their membranes




Cells feed individually but can aggregate to migrate and form a fruiting body


Dictyostelium discoideum is an experimental model for studying the evolution of multicellularity

Illustrate the life cycle of cellular slime molds.
Tubulinids

Tubulinids are a diverse group of amoebozoans with...




They are common unicellular...




Most tubulinids are...

Tubulinids


Tubulinids are a diverse group of amoebozoans with lobe- or tube-shaped pseudopodia


They are common unicellular protists in soil as well as freshwater and marine environments


Most tubulinids are heterotrophic and actively seek and consume bacteria and other protists

Entamoebas

Entamoebas are parasites...




Entamoeba histolytica causes...

Entamoebas


Entamoebas are parasites of vertebrates and some invertebrates


Entamoeba histolytica causes amebic dysentery, the third-leading cause of human death due to eukaryotic parasites

Opisthokonts

Opisthokonts include...

Opisthokonts


Opisthokonts include animals, fungi, and several groups of protists

Concept 28.6: Protists play key roles in ecological...

Protists are found in diverse...


Protists play two key roles in their habitats...

Concept 28.6: Protists play key roles in ecological communities


Protists are found in diverse aquatic and moist terrestrial environments


Protists play two key roles in their habitats: that of symbiont and that of producer

Symbiotic Protists

Some protist symbionts benefit...


Dinoflagellates nourish...


Wood-digesting protists inhabit...



Symbiotic Protists


Some protist symbionts benefit their hosts


Dinoflagellates nourish coral polyps that build reefs


Wood-digesting protists inhabit the gut of termites

Some protists are parasitic

Plasmodium causes...


Pfiesteria shumwayae is a...


Phytophthora ramorum causes...


P. infestans causes...



Some protists are parasitic


Plasmodium causes malaria


Pfiesteria shumwayae is a dinoflagellate that causes fish kills


Phytophthora ramorum causes sudden oak death


P. infestans causes potato late blight, which contributed to the Irish famine of the 19th century

Photosynthetic Protists

Many protists are important...




In aquatic environments, photosynthetic protists and prokaryotes are...




In aquatic environments, photosynthetic protists are limited...




These populations can explode...

Photosynthetic Protists


Many protists are important producers that obtain energy from the sun




In aquatic environments, photosynthetic protists and prokaryotes are the main producers




In aquatic environments, photosynthetic protists are limited by nutrients




These populations can explode when limiting nutrients are added

Biomass of photosynthetic protists has declined as...

Growth of phytoplankton communities relies on...


Warm surface water acts as...

Biomass of photosynthetic protists has declined as sea surface temperature has increased


Growth of phytoplankton communities relies on nutrients delivered from the ocean bottom through the process of upwelling


Warm surface water acts as a barrier to upwelling

If sea surface temperature continues to warm due to global warming, this could have large effects on...

If sea surface temperature continues to warm due to global warming, this could have large effects on:




1. Marine ecosystems


2. Fishery yields


3. The global carbon cycle

Illustrate basic sea surface temperatures across the globe.
Living Small

Even a low-power microscope can reveal a great variety of organisms in a drop of pond water




Protist is the informal name of...




Protists constitute a...




Protista is no longer...

Living Small


Even a low-power microscope can reveal a great variety of organisms in a drop of pond water




Protist is the informal name of the group of mostly unicellular eukaryotes




Advances in eukaryotic systematics have caused the classification of protists to change significantly




Protists constitute a polyphyletic group, and Protista is no longer valid as a kingdom

Illustrate a phylogeny, beginning with the last common ancestor of Excavata, SAR clade, Archaeplastida, and Unikonta.
Illustrate the general divergence of Excavata.

The 5 domains of life are...


These 5 domains came from...