Question 1

Which of the following best describes a clade in a phylogenetic tree?

Accepted Answer

A group of organisms that share a common ancestor and includes all descendants of that ancestor.

Question 2

Which of the following statements about protists is correct?

Accepted Answer

Most protists are unicellular eukaryotes, but some are colonial or multicellular.

Question 3

Which of the following is a key feature distinguishing euglenozoans from other protists?

Accepted Answer

A spiral or crystalline rod inside each flagellum.

Question 4

Which process is responsible for the origin of mitochondria in eukaryotic cells?

Accepted Answer

Primary endosymbiosis of an alpha proteobacterium by a host cell.

Question 5

Which of the following best explains why brown algae are considered analogous, not homologous, to plants?

Accepted Answer

They have similar structures (holdfast, stipe, blades) that evolved independently from those in plants.

Question 6

A researcher discovers a unicellular organism with two equal-sized nuclei, multiple flagella, and no electron transport chains in its mitochondria. Which group does this organism most likely belong to?

Accepted Answer

Diplomonads

Question 7

Which of the following is a real-world consequence of dinoflagellate blooms in aquatic environments?

Accepted Answer

Formation of toxic 'red tides' that can kill fish and other marine life.

Question 8

Which of the following best describes the alternation of generations in brown algae?

Accepted Answer

The life cycle alternates between multicellular haploid gametophytes and multicellular diploid sporophytes.

Question 9

Which of the following is a correct statement about secondary endosymbiosis?

Accepted Answer

A eukaryotic cell engulfs another eukaryotic cell that already contains a plastid.

Question 10

Which of the following protist groups is characterized by threadlike pseudopodia and often forms intricate mineral skeletons?

Accepted Answer

Radiolarians

Question 11

A patient is diagnosed with sleeping sickness after traveling to Africa. Which protist is responsible for this disease, and what is a key cellular feature of this group?

Accepted Answer

Trypanosoma; a single mitochondrion with a kinetoplast

Question 12

Which of the following best explains why photosynthetic protists are considered key producers in aquatic ecosystems?

Accepted Answer

They convert $CO_2$ to organic compounds using energy from light, supporting food webs.

Question 13

Which of the following is a likely ecological consequence if global warming continues to increase sea surface temperatures?

Accepted Answer

Reduced upwelling of nutrient-rich water, leading to declines in phytoplankton and fishery yields.

Question 14

Which of the following statements about the supergroup Unikonta is correct?

Accepted Answer

It includes animals, fungi, and some protists such as amoebozoans.

Question 15

Which of the following is a real-world example of a symbiotic relationship involving protists?

Accepted Answer

Dinoflagellates living within coral polyps, providing them with nutrients via photosynthesis.

Question 16

Which of the following best describes the function of the contractile vacuole in freshwater protists such as Paramecium?

Accepted Answer

It expels excess water to maintain osmotic balance.

Question 17

Which of the following is a correct statement about the evolution of plastids in eukaryotes?

Accepted Answer

Plastids originated from a cyanobacterium engulfed by a heterotrophic eukaryote.

Question 18

Which of the following protist groups is most closely related to land plants?

Accepted Answer

Green algae (specifically charophytes)

Question 19

A scientist observes a protist with a vestigial nucleus (nucleomorph) inside a plastid. What does this indicate about the protist's evolutionary history?

Accepted Answer

It underwent secondary endosymbiosis, engulfing a eukaryotic alga.

Protist Diversity and Eukaryotic Evolution: Structure, Function, and Phylogeny

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