Question 1

Which of the following best explains why molecular clocks may not always provide accurate estimates of evolutionary divergence times?

Accepted Answer

Because natural selection can favor certain mutations, causing irregular rates of molecular change.

Question 2

A researcher is constructing a phylogenetic tree using DNA sequences from several species. Which major challenge must they address to ensure homologous regions are properly compared?

Accepted Answer

Insertions and deletions can shift alignment, making it difficult to identify homologous sequences.

Question 3

Which metabolic process is unique to prokaryotes and plays a critical role in global nutrient cycling?

Accepted Answer

Nitrogen fixation

Question 4

A scientist observes a bacterium that uses $$\mathrm{CO_2$} as $$its carbon source and sunlight as its energy source. How should this organism be classified?

Accepted Answer

Photoautotroph

Question 5

Which of the following is the best evidence supporting the endosymbiotic origin of mitochondria in eukaryotic cells?

Accepted Answer

Mitochondria have a double membrane and their own circular DNA.

Question 6

A fungal species is discovered with septate hyphae and spores produced in sac-like structures. To which phylum does this fungus most likely belong?

Accepted Answer

Ascomycota

Question 7

Which process allows a bacterial cell to acquire new genetic material directly from its environment, potentially increasing its adaptability?

Accepted Answer

Transformation

Question 8

A farmer introduces fungi into phosphorus-poor soil, resulting in improved crop growth due to the fungi penetrating root cells and forming branching structures. Which fungal group is most likely responsible?

Accepted Answer

Glomeromycota

Question 9

Which of the following best describes the ecological role of diatoms in global carbon cycling?

Accepted Answer

Their silica shells sink after blooms, transporting carbon to deep ocean sediments.

Question 10

A mycologist observes a fungal life cycle where two haploid cells fuse cytoplasm but nuclei remain separate for an extended period. What is the name of this stage?

Accepted Answer

Dikaryotic stage

Question 11

Which structure enables prokaryotes to adhere to surfaces or other cells, facilitating the formation of biofilms?

Accepted Answer

Pili and fimbriae

Question 12

A protist is discovered with an excavated feeding groove and a unique crystalline rod in its flagella. To which major eukaryotic clade does it most likely belong?

Accepted Answer

Excavata

Question 13

Which of the following best explains why Gram-negative bacteria are often more resistant to antibiotics than Gram-positive bacteria?

Accepted Answer

They have an additional outer membrane containing lipopolysaccharides.

Question 14

A lichen is observed colonizing bare rock after a volcanic eruption. Why are lichens particularly effective as pioneer species in such environments?

Accepted Answer

They combine photosynthesis from algae with protection and water retention from fungi.

Question 15

Which sequence correctly represents the order of major events during fungal sexual reproduction?

Accepted Answer

Plasmogamy $$\rightarrow$$ karyogamy $$\rightarrow$$ meiosis

Question 16

A forest ecosystem suddenly loses its fungal decomposers. Which ecological consequence would most likely occur first?

Accepted Answer

Accumulation of dead organic material and reduced nutrient cycling

Question 17

Which of the following statements best distinguishes between homology and analogy?

Accepted Answer

Homologies result from shared ancestry; analogies result from convergent evolution.

Question 18

Which metabolic strategy is found only in prokaryotes and not in eukaryotes?

Accepted Answer

Nitrogen fixation

Question 19

A scientist finds a fungus that decomposes lignin in woody plants, playing a major role in forest nutrient cycling. Which fungal group most commonly performs this function?

Accepted Answer

Basidiomycota

Question 20

Which of the following best describes the role of the outgroup in cladistic analysis?

Accepted Answer

It roots the phylogenetic tree by providing a reference point for ancestral traits.

BIO 1306 Practice Exam 2 – Step-by-Step Study Guidance (Chapters 26–31)

Study Guide - Practice Questions

Study Guide - Flashcards