[Campbell Biology P.645] Based on Figure 28.3, which of the following pairs of protist group... | Practice Question

Based on Figure 28.3, which of the following pairs of protist groups likely share a more recent common secondary endosymbiotic ancestor for their plastids?

  • A: Stramenopiles and Alveolates.
  • B: Euglenids and Stramenopiles.
  • C: Red Alga and Green Alga.
  • D: Chlorarachniophytes and Alveolates.

Explanation

Figure 28.3 illustrates that both Stramenopiles and Alveolates acquired their plastids through secondary endosymbiosis involving a red alga. This common origin from a red alga through secondary endosymbiosis indicates a more recent shared ancestry for their plastids compared to pairs involving different secondary endosymbiont types green vs. red alga .