chapter 28: protists
Opisthokonts (Unikonta)
-protists in this group are the ancestors of animal and fungi -amoeba-like or flagellated -free-living (for example, in marine waters), some symbionts -key in researching the origin of animals
Four groups of protists
excavata, SAR, archaeplastida, unikonta
snail-like, coiled, porous test (shell) of calcium carbonate is characteristic of which group? A) diatomsB) foraminiferansC) radiolarians D) gymnamoebas E) ciliates
foraminiferans
protists play key roles as
producers, trophic links, symbionts
most eukaryotic lineages are
protists
A P. bursaria cell that has lost its zoochlorellae is said to be "aposymbiotic." It might be able to replenish its contingent of zoochlorellae by ingesting them without subsequently digesting them. Which of these situations would be most favorable to the re-establishment of resident zoochlorellae, assuming compatible Chlorella are present in P. bursaria's habitat? A) abundant light, no bacterial preyB) abundant light, abundant bacterial prey C) no light, no bacterial preyD) no light, abundant bacterial prey
abundant light, abundant bacterial prey
blade of brown algae have
adaptations that enable their main photosynthetic surfaces to be near the water surface
2) Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because 22 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. E) mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids utilize their own ribosomes.
all eukaryotes have mitochondria wheres many eukaryotes do not have plastids
Which of these are actual mutualistic partnerships that involve a protist and a host organism? A) cellulose-digesting gut protists : wood-eating termitesB) dinoflagellates : reef-building coral animalsC) Trichomonas : humans D) algae : certain foraminiferans E) all except C
all exept C
foraminiferans live in
freshwater and marine environments
stramenopiles appearance
have a hairy flagellum paired with a smooth flagellum
photoautotrophs
have chloroplasts for photosynthesis
radiolarians structure
have delicate, symmetrical internal skeletons generally made of silica
what membrane do alveolates have
have membrane encolsed sacs (alveoli) just under the plasma membrane
diplomonads and parabasalids
have reduced mitochondria, obligate or facultative anaerobes, generally parasites, have flagella
ciliaetes are mostly
heterotrophs - ingest bacteria or other protics mixotrophs and one phototroph
cercozoans are common in living in
marine, freshwater and soil ecosystems
red algae are what group
milticeullar
charaphytes
most closely related to plants
photsynthetic protists are important producers that
convert co2 to organic compounds
dinoflagellates nourish
coral (animals) that build reeds
SAR is highly diverse group of protists defined by
dna similiarties
test
test
You are designing an artificial drug-delivery "cell" that can penetrate animal cells. Which of these protist structures should provide the most likely avenue for research along these lines?A) pseudopodsB) apical complex C) excavated feeding grooves D) nucleomorphsE) mitosomes
apical complex
Which of the following correctly pairs a protist with one of its characteristics? A) diplomonads : micronuclei involved in conjugationB) ciliates : pseudopodsC) apicomplexans : parasitic D) gymnamoebas : calcium carbonate test E) foraminiferans : abundant in soils
apicomplexas: parasites
ciliates are a diverse group of
aquatic (marine and freshwater) and soil protists
tubulinoids what group
are heterotrophic and actively seek and consume bacteria and other protists
most brown algae are ____ and all are _____ but they lack _____
are marine, are multicellular, but they lack true tissues and organs
Green algae often differ from land plants in that some green algae A) are heterotrophs.B) are unicellular.C) have plastids. D) have alternation of generations.E) have cell walls containing cellulose.
are unicellular
reproduction
asexual in some sexual in some both in some
golden algae are named for their
color, which results from their yellow and brown carotenoids
A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic alternation of generations is most probably what type of alga?A) redB) green C) brown D) yellow
brown
The largest seaweeds belong to which group? A) red algaeB) green algaeC) brown algae D) golden algae
brown algae
the largest and most complex algae
brown algae
Which of these statements is false and therefore does not support the hypothesis that certain eukaryotic organelles originated as bacterial endosymbionts? Such organellesA) are roughly the same size as bacteria.B) can be cultured on agar, because they make all their own proteins. C) contain circular DNA molecules.D) have ribosomes that are similar to those of bacteria.E) have internal membranes that contain proteins homologous to those of bacterial plasma membranes.
can be cultured on agar, because they make all their own proteins
Entamoeba histolytica
causes dysentary, infection by drinking cysts in contaminated water the third leading cause of human dead due to eukaryotic paraistes
green algae two main subgroups are
charophytes and chlorphytes
Which of these was not derived from an ancestral alpha proteobacterium? A) chloroplastB) mitochondrionC) hydrogenosome D) mitosome E) kinetoplast
chloroplast
ciliates use what to move and feed
cilia
You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile, using many short extensions of the cytoplasm, each featuring the 9+2 filament pattern. It has well-developed organelles and three nuclei, one large and two small. This organism is most likely to be a member of which group?
ciliates
Which of the following pairs of protists and their characteristics is mismatched? A) apicomplexans : internal parasitesB) golden algae : planktonic producersC) euglenozoans : unicellular flagellates D) ciliates : red tide organismsE) entamoebas : ingestive heterotrophs
ciliates: red tide organisms
A P. bursaria cell that has lost its zoochlorellae is "aposymbiotic." If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship?A) parasiticB) commensalisticC) toxicD) predator-prey
commensalistic
Which process results in genetic recombination, but is separate from the process wherein the population size of Paramecium increases?
conjugation
ciliates have sex via
conjugation, in which two individuals exchange haploid micronuclei
resemblance between slime molds and fungi is due to
convergent evolitoin
Which organisms represent the common ancestor of all photosynthetic plastids found in eukaryotes?A) autotrophic euglenidsB) diatoms C) dinoflagellates D) red algaeE) cyanobacteria
cyanobacteria
The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?A) cyanobacteria green algae land plantsB) cyanobacteria green algae fungi land plants C) red algae brown algae green algae land plants D) red algae cyanobacteria land plantsE) cyanobacteria red algae green algae land plants
cyanobacteria green algae land plants
excavata is characterized by its
cytoskeleton
radiolarians are mostly
marine and heterotrophs
biomass of phytoplankton has
declined as sea surface temperature has increase
Which of the following is correctly described as a primary producer? A) oomyceteB) kinetoplastidC) apicomplexan D) diatomE) radiolarian
diatom
most abundant photosynthetic organisms in the ocean and in lakes
diatom
you are given the task of designing an aquatic protist that is a primary producer. It cannot swim on its own, yet must stay in well-lit surface waters. It must be resistant to physical damage from wave action. It should be most similar to a(n)A) diatom. B) dinoflagellate. C) apicomplexan. D) red alga.E) radiolarian.
diatom
A certain unicellular eukaryote has a siliceous (glasslike) shell and autotrophic nutrition. To which group does it belong?A) dinoflagellatesB) diatoms C) brown algae D) radiolarians E) oomycetes
diatoms
stramenophiles groups
diatoms, golden algae, brown algae
Which group includes members that are important primary producers in ocean food webs, causes red tides that kill many fish, and may even be carnivorous?A) ciliatesB) apicomplexans C) dinoflagellates D) brown algae E) golden algae
dinoflagellates
Which of these taxa contains species that produce potent toxins that can cause extensive fish kills, contaminate shellfish, and poison humans?A) red algaeB) dinoflagellates C) diplomonads D) euglenidsE) golden algae
dinoflagellates
protists are found in
diverse aquatic environments and most terrestrial envrionemts
euglenozoans
diverse clade that represents predatory heterotrophs, photoautotrophs, mixotrophs, or parasites
in single cell protists, each biological function is carried out by
each individual cell
protists diversity had its origin in
endosymbiosis, a relationship in which one species lives inside the cell of another species (the host)
example of tubulinoid
entamoebas are paristes of vertebrae and some invertebrae
Two groups of Euglenozoa
euglenids: commonly found in pond water, perform photosynthesis when sunlight is available and when it is not they become heterotrophic absorning nutrients from their environment kinetoplastids: genus trupanosoma, causes sleeping sickness
1) Protists are alike in that all are A) unicellular.B) eukaryotic.C) symbionts. D) monophyletic. E) autotrophic.
eukaryotic
Which pair of alternatives is highlighted by the life cycle of the cellular slime molds, such as Dictyostelium?A) prokaryotic or eukaryoticB) plant or animal C) unicellular or multicellular D) diploid or haploidE) autotroph or heterotroph
unicellular or multicellular
tubulinoids are common
unicellular protists in soil as well as freshwater and marine environments
golden algae are
uniceullular but some are colonial
Eukaryotes vs Prokaryotes
-have a nucleus and other enclosed organelles such as mitochondira and golgi apparatus -structure is more complex -developed cytoskeleton to have assymetric forms and change shape over time
what happens in diatoms?
-they often bloom, and many dead individuals fall to the ocean floor, where decomposition is slow -the co2 they took up from the atmosphere and incorportated into their biomas is sequestered on the ocean floor up to centuries -some scientists advocate fertilizing the ocean with iron to promote diatom blooms and facilitate movement of co2 to the bottom of the ocean
larger size an greater complexity evolved in green algae by three different mechanisms
1. formation of colonies of indiivudal cells (zygnema) 2. formation of true multicellular bodies by cell division and differentiation (ulva) 3. the repeated division of nuclei with no cytoplasmic diversion (caulerpa)
Which of the following statements concerning living phytoplanktonic organisms are true? 1. They are important members of communities surrounding deep-sea hydrothermal vents.2. They are important primary producers in most aquatic food webs.3. They are important in maintaining oxygen in Earth's seas and atmosphere. 4. They are most often found growing in the sediments of seas and oceans. 5. They can be so concentrated that they affect the color of seawater.
2 3 and 5
Theoretically, which two of the following present the richest potential sources of silica? 1. marine sediments consisting of foram tests2. marine sediments consisting of diatom cases (valves)3. marine sediments consisting of radiolarian shells 4. marine sediments consisting of dinoflagellate plates
2 and 4
You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (e.g., 250 m deep), and can also crawl about and engulf small particles. With which two of these structures would you provide your protist?1. hydrogenosome2. apicoplast3. pseudopods4. chloroplast from red alga5. chloroplast from green alga
3 and 4
The A in SAR and its groups
Alveolates: dinoflagellates (group of flagellates), apicomplexans (group of paraistes) and cilliates (group of protists that move using cili)
excavata: 3 groups
Diplomonads Parabasalids Euglenozoans
R in SAR and its groups
Rhizarians: radiolarians, foraminiferans and cercozoans
SAR groups
Stramenopiles, Alveolates, Rhizarians
25) The following are all characteristic of the water molds (oomycetes) exceptA) the presence of filamentous feeding structures.B) flagellated zoospores.C) a nutritional mode that can result in the decomposition of dead organic matter. D) a morphological similarity to fungi that is the result of evolutionary convergence. E) a feeding plasmodium.
a feeding plasmodium
mitochondria evolved by endosymbiosis by
a proteobacterium
heterotrophs
absorb organic molecular or ingest larger food particles
amoebozoans have three major groups:
amoebas, acellular slime molds, cellular slime molds
many rhizarian species are
amoebas, which move and feed by psudopodia extensions of the cell surface
Cercozoans are a large group of
amoeboid and flagellated protists
unikonta includes two clades
amoebozoans (protists only) and opisthokonts (plants fungi and animals)
plastids evolved later by endosymbiosis of explain diversity of plastids
cyanobacterium 1. cyanobacteria --> primary endosymbiosis --> green algae --> secondary symbiosis --> plastid in euglenids 2. cyanobacteria --> primary endosymbiosis --> green algae --> chlorarachniophytes 3. c cyanobacteria --> primary endosymbiosis --> red algae --> secondary symbiosis --> plastid in sramenopiles 4. cyanobacteria --> primary endosymbiosis --> red algae --> secondary symbiosis --> alveolates
The best evidence for not classifying the slime molds as fungi comes from slime molds' A) DNA sequences.B) nutritional modes.C) choice of habitats. 11 D) physical appearance. E) reproductive methods.
dna sequences
red algae do not have
flagellated gametes, so they depend on water currents to bring gametes together for fertilizaition
where can you find foram test?
foram tests (shells) form an extensive fossil record in marine sediments
According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate?A) from infoldings of the plasma membrane, coupled with mutations of genes for proteins in energy-transfer reactions 1 B) from engulfed, originally free-living prokaryotesC) by secondary endosymbiosisD) from the nuclear envelope folding outward and forming mitochondrial membranes E) when a protoeukaryote engaged in a symbiotic relationship with a protobiont
from engulfed, originally free living prokaryotes
f the chloroplasts of the zoochlorellae are very similar to those found in the photosynthetic cells of land plants, then Chlorella is probably what type of alga?A) redB) green C) brown D) golden
green
The chloroplasts of all of the following are derived from ancestral red algae, except those of A) golden algae.B) diatoms.C) dinoflagellates. D) green algae. E) brown algae.
green algae
Which taxon of eukaryotic organisms is thought to be directly ancestral to the plant kingdom?A) golden algaeB) radiolarians C) foraminiferans D) apicomplexans E) green algae
green algae
Which protists are in the same eukaryotic "supergroup" as land plants? A) green algaeB) dinoflagellatesC) red algae D) brown algaeE) A and C are both correct
green algae and red algae
dinoflagellates strucutre
have two flagella and each cell is reinforced by cellulos plates
Rhizarian amoebas differ from amoebas in other clades by...
having threadlike psuedopodia
cercozoans mostly in groups in
heterotrophs, including parasites and predators
foraminiferans have what group
heterotrops but some are also noursished by the photocynthetic activity of simbiotic algae living in their tests (shell)
heterotrophic protists link this production to
higher tropic levels (fish nd whales)
A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following?A) thalliB) bladders C) bladesD) holdfastsE) gel-forming polysaccharides
holdfasts
Which process allowed the nucleomorphs of chlorarachniophytes to be first reduced, and then (in a few species) lost altogether, without the loss of any genetic information?A) conjugationB) horizontal gene transfer C) binary fission D) phagocytosis E) meiosis
horizontal gene transfer
Why is the filamentous morphology of the water molds considered a case of convergent evolution with the hyphae (threads) of fungi?A) Fungi are closely related to the water molds.B) Body shape reflects ancestor-descendant relationships among organisms. C) In both cases, filamentous shape is an adaptation for the absorptive nutritional mode of a decomposer.D) Filamentous body shape is evolutionarily ancestral for all eukaryotes.E) Both A and B are correct.
in both cases, filamentous shape is an adaptation for the absorptive nutritional mode of a decomposer
apicomplexans spread through their host as
infections cells (sporoxoites) which at one end have an apex specialized for penetrating host cells and tissues
If one were to apply the most recent technique used to fight potato late blight to the fight against the malarial infection of humans, then one wouldA) increase the dosage of the least-expensive antimalarial drug administered to humans.B) increase the dosage of the most common pesticide used to kill Anopheles mosquitoes. C) introduce a predator of the malarial parasite into infected humans.D) use a "cocktail" of at least three different pesticides against Anopheles mosquitoes.E) insert genes from a Plasmodium-resistant strain of mosquito into Anopheles mosquitoes.
insert genes from a plasmodium-resistant straint of mosquite into anophele mosquitos
An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival? 2 A) It relies on photosystems that float freely in its cytosol.B) It must have gained extra mitochondria when it lost its plastids. C) It engulfs organic material by phagocytosis or by absorption. D) It has an endospore.E) It is protected by a siliceous case.
it enfulds organic material by phagocytosis or absorption
If the Archaeplastidae are eventually designated a kingdom, and if the land plants are excluded from this kingdom, then what will be true of this new kingdom?A) It will be monophyletic.B) It will more accurately depict evolutionary relationships than does the current taxonomy. C) It will be paraphyletic. D) It will be a true clade. E) It will be polyphyletic.
it will be paraphyletic
Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do the white blood cells of animals. If one were to erect a taxon that included all organisms that have cells with pseudpods, what would be true of such a taxon?A) It would be polyphyletic. B) It would be paraphyletic.C) It would be monophyletic.D) It would include all eukaryotes.
it would be polyphyletic
Typically as cells grow, their increase in volume outpaces their increase in surface area, and continued survival requires undergoing asexual reproduction to reestablish a healthy surface area to volume ratio. Thus, which of these is least likely to contribute to the ability of a single-celled foraminiferan to grow to a diameter of several centimeters? A) Its threadlike pseudopods dramatically increase its surface area to volume ratio. B) Its symbiotic algae provide oxygen to the cytoplasm.C) Its symbiotic algae absorb metabolic waste products from the cytoplasm.D) Its symbiotic algae provide glucose to the cytoplasm. E) Its calcium carbonate test contributes extra mass.
its calcium carbonate test contributes extra mass
cilliates have two type of nuclei
large macronuclei and tiny micronuclei
chlorophytes
live in fresh water but many are marine and some live in damp soil or as symbionts in lichens
amoeboxoans are amoebas that have
love or tube shaped, psudopodia (in rhizarians the pseudopodia is threadlike)
he motility that permits P. bursaria to move toward a light source is provided by A) pseudopods.B) a single flagellum composed of the protein, flagellin.C) a single flagellum featuring the 9+2 pattern. D) many cilia.E) contractile vacuoles.
many cilia
Which statement regarding resistance is false?A) Many of the oomycetes that cause potato late blight have become resistant to pesticides.B) Many of the mosquitoes that transmit malaria to humans have become resistant to pesticides. C) Many of the malarial parasites have become resistant to antimalarial drugs.D) Many humans have become resistant to antimalarial drugs.E) Trichomonas vaginalis is resistant to the normal acidity of the human vagina.
many humans become resistant to antimalarial drugs
If both host and alga can survive apart from each other, then which of these best accounts for their ability to live together?A) genome fusionB) horizontal gene transfer C) genetic recombination D) conjugationE) metabolic cooperation
metabolic cooperation
The strongest evidence for the endosymbiotic origin of eukaryotic organelles is the similarity between extant prokaryotes and which of the following?A) nuclei and chloroplastsB) mitochondria and chloroplasts C) cilia and mitochondria D) mitochondria and nuclei E) mitochondria and cilia
mitochondria and chloroplasts
In life cycles with an alternation of generations, multicellular haploid forms alternate with A) unicellular haploid forms.B) unicellular diploid forms.C) multicellular haploid forms. D) multicellular diploid forms. E) multicellular polyploid forms.
multicellular dipoloid forms
phytoplankton relies on
nutries delivered from the ocean bottom by upwelling, which is bloked . by warm surface water
The Irish potato famine was caused by an organism that belongs to which group? A) ciliatesB) oomycetesC) diatoms D) apicomplexans E) dinoflagellates
oomycetes
what group are green algae
paraphyletic group
apicomplexans are mostly
parasites of animals, some cause serious human disease
example of cercozoan
paulinella chromatophora is an autotroph with a unique photosynthetic structure called a chromatophore
mixotrophs
photosyntehsis and heterotrophy
stramenopiles's groups includes some of the omst imporatnt ...
photosynthetic organisms on earther
brown algae have gas filled bubble shaped floats to keep theyr
photosynthetic strucures near the water of the surface
golden algae are all
photosynthetic, some are mixotrophs
dinoflagellates are diverse group of aquatic
phototrophs, mixotrophs, and heterotrophs, abundant in both marine and freshwater phytoplankton
red algae are reddish due to
phycoerythrin
diatoms are highly diverse and a major component of
phytoplankton
Which two genera have members that can evade the human immune system by frequently changing their surface proteins?1. Plasmodium2. Trichomonas 3. Paramecium 4. Trypanosoma 5. Entamoeba
plasmodium and trypanosoma
example of apicomplexans:
plasmodium, parasite that causes malaria requires both mosquitos and humans to complete its life cycle
protist is the informal name for an array of
polyphyletic (more than one common ancestor)
alveolates include wide range of
potosyntehtic and heterotrophic protists
the main morpholgoical feature in euglenozoans
presense of a rod with either a sprial or crystalline structure inside each of their flagella
who exhibits more functional and structural diversity?
protists exhibit more functional and structural diversity than the other groups in eukaryotes (plants animal and fungi)
organisms in eukaryotes are mostly
protists, and most protists are unicellular
Which of the following produce the dense glassy ooze found in certain areas of the deep- ocean floor?A) foramsB) dinoflagellates C) radiolarians D) ciliatesE) apicomplexans
radiolarians
Thread-like pseudopods that can perform phagocytosis are generally characteristic of which group?A) radiolarians and foramsB) gymnamoebas C) entamoebasD) amoeboid stage of cellular slime molds E) oomycetes
radiolarians and forums
A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga probably belongs to which group?A) red algae 10 B) brown algae C) green algaeD) dinoflagellates E) golden algae
red algae
Which group is incorrectly paired with its description?A) rhizarians-morphologically diverse group defined by DNA similarities B) diatoms-important producers in aquatic communitiesC) red algae-acquired plastids by secondary endosymbiosisD) apicomplexans-parasites with intricate life cyclesE) diplomonads-protists with modified mitochondria
red algae - acquired by plastids by secondary endosymbiosis
archaeplastia groups
red algae, green algae, plants
_____ underwent secondary endosymbiosis that were ingested by ____
red and green algae -- ingested by heterotrophic euarytoe
dinoflagellate blooms cause
red tides - presence of carotenoids, the most common pigment in dinoflagellete plastids
ciliates help
reminants digest cellulose
plantike structures of brown algae
rootlike: the holdfast (anchors the alga) stem like: the stipe supports the leaflike: blades but unlike plants, brown algae lack true tissue
ciliates: some symbionts in
rumen
brown algae are sometimes called
seaweed
largest red algae
seaweeds, which are most abundant large algae in tropical coastal waters
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.E) budding of the plastids from the nuclear envelope.
secondary endosymbiosis
the life cycle of most apicomplexans have
sexual and a sexual stages and need two or more hosts
2) Biologists have long been aware that the defunct kingdom Protista is paraphyletic. Which of these statements is both true and consistent with this conclusion?A) Many species within this kingdom were once classified as monerans.B) Animals, plants, and fungi arose from different protist ancestors. C) The eukaryotic condition has evolved only once among the protists, and all eukaryotes are descendants of that first eukaryotic cell.D) Chloroplasts among various protists are similar to those found in prokaryotes.E) Some protists, all animals, and all fungi share a protist common ancestor, but these protists, animals, and fungi are currently assigned to three different kingdoms.
some protists, all animals and all fungi share a protist common ancestor, but these protists, animals, and fungi, are currently assigned to three different kingdoms
slime molds body
spor producing fruiting bodies
foraminiferans have a
test, a shell of calcium carbonate
A biologist discovers a new unicellullar organism that possesses more than two flagella and two small, but equal-sized, nuclei. The organism has reduced mitochondria (mitosomes), no chloroplasts, and is anaerobic. To which clade does this organism probably belong?A) monera B) the diplomonads C) the ciliatesD) protistaE) the euglenids
the diplomonads
wood digesting protists inhabit
the gut of termites
Which of the following statements concerning protists is false?A) All protists are eukaryotic organisms; many are unicellular or colonial.B) The primary organism that transmits malaria to humans by its bite is the tsetse fly.C) All apicomplexans are parasitic.D) Cellular slime molds have an amoeboid stage that may be followed by a stage during which spores are produced.E) Euglenozoans that are mixotrophic contain chloroplasts.
the primary orgnaisms that transmits malaria to humans by its bite is the tsetse fly
15) Which of these statements about dinoflagellates is false? A) They possess two flagella.B) Some cause red tides.C) Their walls are composed of cellulose plates. D) Many types contain chlorophyll.E) Their dead cells accumulate on the seafloor, and are mined to serve as a filtering material.
their dead cells accumulate on the seafloor and are mined to serve as filtering material
green algae are named after
their green grass chloroplast
Which of the following is not characteristic of ciliates?A) They use cilia as locomotory structures or as feeding structures.B) They are relatively complex cells.C) They can exchange genetic material with other ciliates by the process of mitosis. D) Most live as solitary cells in fresh water.E) They have two or more nuclei.
they can exchange genetic material with other ciliates by the process of mitosis
What makes certain red algae appear red?A) They live in warm coastal waters.B) They possess pigments that reflect and transmit red light. C) They use red light for photosynthesis.D) They lack chlorophyll.E) They contain the pigment bacteriorhodopsin.
they posess pigments that reflect and transmit red light
if sea surface temperature continues to warm due to climate change,
this could have large effects on marine ecoystems, fishery yields, and global carbon cycle
structure of diatoms
unicellular algae with a unique two part, glass like wall of silicon dioxide
slime molds descended from
unicellular ancestorrs - it is an example of indepednent orifin of multicellularity in eukaryotes
protists are
unicellular but some are colonial and multicellular
28) Using dead diatoms to "pump" CO2 to the seafloor is feasible only if dead diatoms sink quickly. Consequently, application of mineral fertilizers, such as iron, should be most effective at times when diatomA) valves are thickest, and laminarin is being produced rather than oil.B) valves are thickest, and oil is being produced rather than laminarin. C) valves are thinnest, and laminarin is being produced rather than oil. D) valves are thinnest, and oil is being produced rather than laminarin.
valves are the thickest, and laminarin is being produced rather than oil
