Which statement is supported by the figure below?

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Which statement is supported by the figure below?

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BlackTom AI · Accepted Answer

Endosymbiotic theory places the origin of mitochondria earlier than that of chloroplasts, so mitochondria evolved before chloroplasts.

1) Relevant concepts: The diagram is a phylogenetic tree showing major lineages (Bacteria, Archaea, Eukarya) and arrows marking endosymbiotic events. Endosymbiosis is the process by which one cell (an ancestral host) engulfed another cell (a bacterial ancestor) and the engulfed cell became an organelle. Mitochondria are derived from an ancestral proteobacterium and chloroplasts from cyanobacteria. The position of the arrows on a phylogenetic tree indicates the relative timing of these events.

2) Step‑by‑step reading of the figure:
- Follow the trunk from "Life" to the branch that becomes Eukarya. An orange dashed arrow labeled “Mitochondria” points into the base of the Eukarya branch, indicating the mitochondrial endosymbiosis occurred at or just before the origin of eukaryotes.
- A separate dashed arrow labeled “Chloroplasts” attaches further out on a specific eukaryotic branch (plants/algae), indicating chloroplast acquisition happened later in a descendant lineage, not at the base of Eukarya.

3) Intermediate inference steps:
- Because the mitochondrion arrow is placed at the base of Eukarya, all eukaryotes inherited mitochondria (or their derivatives).
- The chloroplast arrow is nested within the eukaryotic subtree, so only the lineage that acquired chloroplasts (plants and some algae) has them.

4) Why the correct answer is correct: The tree visually and conceptually shows the mitochondrial endosymbiotic event preceding the chloroplast endosymbiotic event; this matches the well‑accepted evolutionary sequence.

5) Why other options are incorrect:
- "Chloroplasts are found in bacteria." Incorrect — chloroplasts are organelles in eukaryotes; they originated from cyanobacteria by endosymbiosis but are not present as chloroplast organelles in bacteria.
- "Plants contain chloroplasts but not mitochondria." Incorrect — plants have both chloroplasts and mitochondria.
- "No members of Eukarya contain both chloroplasts and mitochondria." Incorrect — many eukaryotes (plants and algae) contain both organelles.

Conclusion: The figure supports the statement "Mitochondria evolved before chloroplasts," which matches the provided correct answer.

Which statement is supported by the figure below? Having trouble viewing the image - download it here Actions单项选择题

类似问题

The first eukaryotic common ancestor was an endosymbiotic relationship between two cells. What was a benefit from this relationship?

Based on current evidence, one of the earliest events leading from the first eukaryotic common ancestor to the modern eukaryotic cell would be:

Which of the following statements does NOT provide evidence in support of the endosymbiotic origin of eukaryotic cells?

Ancestors of which type of bacteria likely gave rise to chloroplasts?

Endosymbiotic theory explains...

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