Chapter 25

What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth? 1. Origin of mitochondria. 2. Origin of multicellular eukaryotes. 3. Origin of chloroplasts. 4. Origin of cyanobacteria. 5. Origin of fungal-plant symbioses. A) 4, 3, 2, 1, 5 B) 4, 1, 2, 3, 5 C) 4, 1, 3, 2, 5 D) 4, 3, 1, 5, 2 E) 4, 3, 1, 2, 5

C) 4, 1, 3, 2, 5

The cysts of Giardia are most analogous to the which of the following? A) Mitochondria of ancestral diplomonads. B) Nuclei of archaeans. C) Endospores of bacteria. D) Capsids of viruses.

C) Endospores of bacteria.

The chloroplasts of all of the following are thought to be derived from ancestral red algae, except _____________ A) golden algae. B) diatoms. C) dinoflagellates. D) green algae. E) brown algae.

D) green algae.

Book: The evolution of complex multicellularity in eukaryotes A) occurred only once, in the common ancestor of all eukaryotes B) occurred only once, in the common ancestor of all multicellular eukaryotes C) occurred only once, in the animal lineage D) occurred independently in several eukaryotic lineages

D) occurred independently in several eukaryotic lineages

Given its mode of reproduction and internal structures, which of the following should be expected to occur in Giardia at some stage of its life cycle? 1. Separation (segregation) of daughter chromosomes. 2. Crossing over. 3. Meiosis. A) 1 only B) 3 only C) 1 and 2 D) 1 and 3 E) 2 and 3

A) 1 only 1. Separation (segregation) of daughter chromosomes.

Which of the following is the most likely sequence of events, from earliest to most recent, in the evolution of sponges (organisms with many cells that have different functions)? 1) single-celled eukaryote 2) single-celled prokaryote 3) multicellular eukaryote 4) colonial eukaryote A) 2, 1, 4, 3 B) 2, 1, 3, 4 C) 1, 2, 3, 4 D) 1, 2, 4, 3

A) 2, 1, 4, 3

The oldest fossil eukaryote that can be resolved taxonomically is which of the following? A) A red alga that lived 1.2 billion years ago. B) A red alga that lived 635 million years ago. C) A fungus that lived 2 billion years ago. D) A fungus that lived 550 million years ago. E) An Ediacaran that lived 550 million years ago.

A) A red alga that lived 1.2 billion years ago.

Which of the following statements concerning protists is true? A) All protists have mitochondria, although in some species they are much reduced and known by different names. B) The primary organism that transmits malaria to humans by its bite is the tsetse fly. C) All apicomplexans are autotrophic. D) All slime molds have an amoeboid stage that may be followed by a stage during which spores are produced. E) Euglenozoans that are mixotrophic lack functional chloroplasts.

A) All protists have mitochondria, although in some species they are much reduced and known by different names.

Which of the following was derived from an ancestral cyanobacterium? 2 A) Chloroplast B) Mitochondrion C) Hydrogenosome D) Mitosome E) Two of the responses above are correct.

A) Chloroplast

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence? 3 A) Cyanobacteria → green algae → land plants B) Cyanobacteria → green algae → fungi → land plants C) Red algae → brown algae → green algae → land plants D) Cyanobacteria → red algae → green algae → land plants

A) Cyanobacteria → green algae → land plants

Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of which group(s)? A) Radiolarians and forams B) Gymnamoebas C) Entamoebas D) Amoeboid stage of cellular slime molds E) Oomycetes

A) Radiolarians and forams

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 B) Brown algae C) Green algae D) Dinoflagellates E) Golden algae

A) Red algae

The best evidence for not classifying the slime molds as fungi comes from? A) Slime molds' DNA sequences. B) Slime molds' nutritional modes. C) Slime molds' choice of habitats. D) Slime molds' physical appearance. E) Slime molds' reproductive methods.

A) Slime molds' DNA sequences.

Book: The oldest fossil eukaryote that can be resolved taxonomically is of A) a red alga that lived 1.2 billion years ago B) a green alga that lived 635 million years ago C) a fungus that lived 2 billion years ago D) an Ediacaran that lived 550 million years ago

A) a red alga that lived 1.2 billion years ago

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 diatom valves ____________________________________. A) are thickest, and laminarin is being produced rather than oil. B) are thickest, and oil is being produced rather than laminarin. C) are thinnest, and laminarin is being produced rather than oil. D) are thinnest, and oil is being produced rather than laminarin.

A) are thickest, and laminarin is being produced rather than oil.

Evolution of which of the following involved primary endocytosis only? A) Green alga. B) Stramenopiles. C) Dinoflagellates. D) Euglenids E) Chlorarachinophytes

A) green alga

Which two genera have members that can evade the human immune system by frequently changing their surface proteins? 1. Plasmodium 2. Trichomonas 3. Paramecium 4. Trypanosoma 5. Entamoeba A) 1 and 2 B) 1 and 4 C) 2 and 3 D) 2 and 4 E) 4 and 5

B) 1 and 4 1. Plasmodium 4. Trypanosoma

Green algae differ from land plants in that many green algae? A) Are heterotrophs. B) Are unicellular. C) Have plastids. D) Have alternation of generations. E) Have cell walls containing cellulose.

B) Are unicellular.

According to the endosymbiotic theory of the origin of eukaryotic cells, how did plastids originate? A) From infoldings of the plasma membrane, coupled with mutations of genes for proteins in cytoskeletal organization B) From an engulfed, cyanobacterium C) By secondary endosymbiosis D) From the nuclear envelope folding outward and forming plastidal membranes E) When a protoeukaryote engaged in a symbiotic relationship with a protocell

B) From an engulfed, cyanobacterium

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 B) From engulfed, originally free-living proteobacteria C) By secondary endosymbiosis D) From the nuclear envelope folding outward and forming mitochondrial membranes E) When a protoeukaryote engaged in a symbiotic relationship with a protocell

B) From engulfed, originally free-living proteobacteria

The genome of modern chloroplasts is roughly 50% of the size of the genome of the cyanobacterium from which it is thought to have been derived. In comparison, the genome of P. chromatophora's cyanelle is only slightly reduced relative to the size of the genome of the cyanobacterium from which it is thought to have been derived. What is a valid hypothesis that can be drawn from this comparison? A) Lytic phage infections have targeted the chloroplast genome more often than the P. chromatophora genome. B) P. chromatophora's cyanelle is the result of an evolutionarily recent endosymbiosis. C) The genome of the chloroplast ancestor contained many more introns that could be lost without harm, compared to the cyanelle's genome. D) All three of the hypotheses above are valid. E) Only A and B are correct.

B) P. chromatophora's cyanelle is the result of an evolutionarily recent endosymbiosis.

Living diatoms contain brownish plastids. If global warming causes blooms of diatoms in Earth's ocean surfaces, how might this be harmful to the animals that build coral reefs? 4 A) The coral animals, which capture planktonic organisms, may be outcompeted by the diatoms. B) The coral animals' endosymbiotic dinoflagellates may get "shaded out" by the diatoms. C) The coral animals may die from overeating the plentiful diatoms, with their cases of silica. D) The diatoms' photosynthetic output may over-oxygenate the water.

B) The coral animals' endosymbiotic dinoflagellates may get "shaded out" by the diatoms.

Book: Biologists think that endosymbiosis gave rise to mitochondria before plastids partly because A) the products of photosynthesis could not be metabolized without mitochondrial enzymes B) all eukaryotes have mitochondria (or their remnants), wheras 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), wheras many eukaryotes do not have plastids

All protists are ________ A) unicellular. B) eukaryotic. C) symbionts. D) monophyletic. E) mixotrophic.

B) eukaryotic.

Book:Which group is incorrectly paired with its description? A) diatoms - important producers in aquatic communities B) red algae - acquired plastids by secondary endosymbiosis C) apicomplexans - parasites with intricate life cycles D) diplomonads - protists with modified mitochondria

B) red algae - acquired plastids by secondary endosymbiosis

Water's density and, consequently, its buoyancy decrease at warmer temperatures. Based on this consideration and using data from Table I, at which time of year should one expect diatoms to be storing excess calories mostly as oil? A) Mid-winter B) Early spring C) Late summer D) Late fall

C) Late summer

Multicellular colonies of plant cells adhere to each other primarily by ________, whereas multicellular colonies of animal cells are typically held together by ________. A) fusion of cellular membranes; cell walls B) cell walls; fused cellular membranes C) cell walls; proteins D) interlocking chloroplasts; interlocking mitochondria E) interlocking cellular shapes (like puzzle pieces); large, calcified capsules

C) cell walls; proteins

Book: Based on the phylogenic tree in figure 25.9, which of the following statements is correct? A) the most recent common ancestor of excavata is older than that of SAR B) the most recent common ancestor of red algae and plants is older than that of nuclearilds and fungi 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

What must occur for asexual reproduction to be successful in P. chromatophora? 1. Mitosis 2. S phase 3. Meiosis 4. Equal distribution of cyanelles during cytokinesis A) 1 only B) 1 and 2 C) 1, 2, and 3 D) 1, 2, and 4 E) 2, 3, and 4

D) 1, 2, and 4 1. Mitosis 2. S phase 4. Equal distribution of cyanelles during cytokinesis

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.

D) secondary endosymbiosis.

You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (for example, 250 m deep), and can also crawl about and engulf small particles. With which two of the following structures would you provide your protist? 1. Hydrogenosome. 2. Apicoplast. 3. Pseudopods. 4. Chloroplast from red alga. 5. Chloroplast from green alga. A) 1 and 2 B) 2 and 3 C) 2 and 4 D) 3 and 4 E) 4 and 5

D) 3 and 4

All protists are which of the following? A) Single cells only. B) Multicellular. C) Fungi. D) Eucaryotic cells. E) Bacteria.

D) Eukaryotic Cells

The closest living relative of P. chromatophora is the heterotroph P. ovalis. What type of evidence permits biologists to make this claim about relatedness? A) Morphological B) Ecological C) Biochemical D) Genetic E) Fossil

D) Genetic

For question 27: Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gathers at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae. 27. The motility that permits P. bursaria to move toward a light source is provided by which of the following? 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.

D) Many cilia.

Book: 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